# Outdoor Reset



## Sparky (Feb 16, 2017)

Over the last 3 years I have been testing, tweaking and doing different things to my EC 100
First I finally got a good supply of dry wood -20% Second I got my baro damper settings correct, Third I did the chain turbulators (Wow I can clean the tubes in less than a half hour) I also installed a SS plate overlay on my nozzle. (I went with holes instead of a slot, I figured I could slot it if that didn't work) The boiler works great with it we will see if it protects the nozzle in time. I also started weighing my wood. I figured that any changes I made I need to know for sure if they were doing any good. So far so good. I have a 2400 sq ft 2 story house built in 2008, I have since blown in 6" of cellulose in attic and spray foamed the box sill and down 3' on basement walls. I'm avg. 165 lbs a day (good or bad?) As I get better at cleaning the tubes my flue temps have decreased low to mid 300s (good or bad?) I am considering doing the outdoor reset (continuous flow) for a couple of reasons. One I have radiant heat on the first floor and on sunny days (a great solar gain for me) my house is hot, by the time the radiant kicks on it too cold. Second is I use approx. 15 degrees of water from 7am to around 4pm when I refire again (any savings) I have basic baseboard on second floor (toe kick heater in 2nd fl bath) not sure how that will be affected. I believe it will cost me $700-$1,000 (will get into the equipment details later) to do this not sure if its worth the investment? I also love playing with my boiler and going on this site to see what others are doing. (my wife says I have a problem) Thanks for your input.


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## TCaldwell (Feb 16, 2017)

Sparky, then a lot of us have a problem! From my experience odr will give a more even heat, making the house feel more comfortable. Typically and especially during the shoulder seasons you can run storage much lower, more flexibility for firing times. However it doesn't change your heat load, on a cold design day you will still need a relatively high mix temp as with a conventional system. 700 to 1000 is conservative, overall I'm glad I made the change


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## Chris Hoskin (Feb 17, 2017)

sorry for the shameless plug, but I think this is just what you are looking for: https://store.tarmusa.com/collections/lk-armatur-featured-products/products/lk110-smart-control  Because of your solar gain issue you may want to choose the LK120 or LK130 that also monitor room temp.


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## Sparky (Feb 17, 2017)

Thanks Chris I just got off the phone with TCaldwell he gave me the same advice   
I'm going to call them next week
Didn't see outdoor sensor in kit or how to do 2 stories with different type of heat and different temperatures?


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## JohnDolz (Feb 17, 2017)

Sparky said:


> Thanks Chris I just got off the phone with TCaldwell he gave me the same advice
> I'm going to call them next week
> Didn't see outdoor sensor in kit or how to do 2 stories with different type of heat and different temperatures?
> 
> ...


I would think you could use 2 ODR's controlling 2 separate mixing valves that would feed the different zones. I have my system use similar to that but my 2nd "zone" is DHW. All of my controls are built into my boiler which can then control 3 different mixing valves (2 heating zones + DHW) via 1 outdoor sensor.


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## Sparky (Feb 17, 2017)

I'm calling tarm next week and hopefully they have a solution. I'm hoping 1 mixing valve but we will see I'll keep you posted
Thanks


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## JohnDolz (Feb 17, 2017)

Sparky said:


> I'm calling tarm next week and hopefully they have a solution. I'm hoping 1 mixing valve but we will see I'll keep you posted
> Thanks
> 
> 
> Sent from my iPhone using Tapatalk



I am definitely not an expert and don't know the various solutions out there but if you want to use very low flow temps then you will need the zone get get heat almost 24x7. So if you have 2 zones that need 2 different water temps I would think you would need 2 mixing valves. That being said I have 1 mixing valve that is feeding 5 zones. I use the lowest possible flow temp that will meet the need of the 5 zones and then use thermostats to "fine tune" for each zone. Good luck!


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## Sparky (Feb 18, 2017)

Hey Chris, When I read your post from my phone I didn't realize you were from Tarm. So I have a question. If I have radiant on my first floor and I like it 73 degrees. I have baseboard on my second floor and I like it 70 degrees. Can I do this with one reset mixing valve controller?


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## JohnDolz (Feb 18, 2017)

Sparky said:


> Hey Chris, When I read your post from my phone I didn't realize you were from Tarm. So I have a question. If I have radiant on my first floor and I like it 73 degrees. I have baseboard on my second floor and I like it 70 degrees. Can I do this with one reset mixing valve controller?


It is not so much what temperature you would like the rooms to be but more a question of what design temp you need to get you there. I think your challenge is that your radiant floor will want much lower temp water than your baseboards. 1 mixing valve will create 1 temp water, I believe you will need 2. I was chatting with a guy at a local nursery and if my memory serves me he said he always runs the same temp through the radiant floor, regardless of outside temp, otherwise the floor is too hot to walk on. If that is the case I would think that you could use 1 Outdoor reset tied to a mixing valve and the another mixing valve from there that would feed that radiant floor at a fixed water temp. Like I said I am definitely no expert but I have a couple years of experience playing with ODR with 2 mixing valves feeding 5 zones plus DHW with 3 different types of emitters, With TCaldwell's help I think we have a system that is working pretty well and fairly efficient. You are welcome to pick what little is in my brain any time or feel free to come have a look.


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## Sparky (Feb 18, 2017)

Tom is a pretty smart guy
Talking with him on Friday had my small brain spinning 
But after doing some reading this weekend he started making sense 
But one thought I did have is when I'm doing the odr I will always be running off storage. Now if my house is calling for heat it goes to the house first with a little going to storage but I should never have a call for heat (at least not a high temp heat) right?


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## JohnDolz (Feb 18, 2017)

Sparky said:


> Tom is a pretty smart guy
> Talking with him on Friday had my small brain spinning
> But after doing some reading this weekend he started making sense
> But one thought I did have is when I'm doing the odr I will always be running off storage. Now if my house is calling for heat it goes to the house first with a little going to storage but I should never have a call for heat (at least not a high temp heat) right?
> ...


I would need to see the piping going in and out of your storage to give you a useful answer. It sounds like you are plumbed as a 2-pipe storage system, if this is correct the mixing valve will be placed in the pipe that is flowing water to your zones. It will call for less hot water to the zones and send more to your storage when the boiler is running (mixing in return water to hit the target design temp). In my house I have things set so 3 out of my 5 zones call almost 24x7 - I use the thermostats to accommodate the solar effect as the sun moves and hits different zones throughout the day. If my house is at temperature I am usually running 120 - 135 degree design temp when it is below 35 out. I actually have a setback feature so I let me house cool down 5 or 6 degrees at night. My system also has an indoor sensor so when I want my house to start recovering the Indoor sensor sees that the design temp set by ODR will not do the job (very hard to recover with low design temps) so the Indoor Sensor overrides ODR. Even then I am usually below 150 degrees, except for those low single digit and below zero days. Can't say I ever remember seeing above 160......and yes he is a very smart guy.


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## TCaldwell (Feb 18, 2017)

If your supply currently comes from your storage at 150 or above you probably won't have a call from the secondary boiler unless your design day has been exceeded with a exceptionally cold day. As John says he only gets near that water temp when he is recovering from a nighttime setback. You'd be surprised what a constant circulation of low temp water will heat, for me it's usually between 120 and 138 throughout the course of a day. 
The the outdoor reset controller/valve is the one Chris sent you the link about. If you were to put a odr valve from your storage and you have a radiant mix valve downstream, the odr will dictate the radiant temp and the radiant mix valve will act as a high temp limit. If you plumb your radiant mix zone upstream of the odr mix valve you will have a more consistent floor temp. This might not matter, dependant on the room.


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## Sparky (Feb 19, 2017)

Here is what I'm thinking, I set the design temp for the second floor baseboard, then the first floor with radiant will be a little hotter than needed, but will be tempered down by the manual tempering valve already installed in the system? I pretty sure I am going with the LK130 from Tarm it has the outdoor sensor and the indoor sensor. I think I have how I'm going to install it figured out, But as I stated before now if there is flow from my boiler and my house needs it it goes straight to the zones. But now I will always be running from and feeding storage? I believe I can install this so I can resort back to the way it is now. (if in design stage my house gets cold) I don't want Mrs. Sparky to get upset, she already thinks I have an obsession with my boiler


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## TCaldwell (Feb 19, 2017)

You will be feeding the lk130 from storage on the hot side of the 130, the cold supply on the 130 will be a leg from your zone return and the design mix will be your new zone supply. For instance today my storage is currently 155, outside temp is 48 calling for a design temp of 109. If I was using a 3way valve most of hot supply water from storage would be closed off, staying in storag, the cooler return water would be returning to the boiler for reheat. Not sure if this answers your question 
  As far smarts, I just followed John on odr, I was skeptical but after seeing his in action, it makes sense!


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## TCaldwell (Feb 19, 2017)

Mts sparky should be fine, as you will have indoor feedback to bump up the mix temp when needed. You will notice the baseboard will be much quieter and the temp more even, happy wife, happy life!


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## Sparky (Feb 20, 2017)

Well I'm going to give ODR a try. I ordered the parts today from Tarm (they are close by) (NH) so I should see them tomorrow or Wednesday maybe have it installed by weekend 
Will keep you posted 


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## JohnDolz (Feb 20, 2017)

Great, good luck! I am not familiar with the Tarm ODR but I do have an ODR in my propane boiler that I think works the same way. I found the predetermined (based on emitter type) Design curve to be too narrow and too high.My wood boiler controls my mixing valve via what they call a "Slope for flow temperature" (see link to Product manual - look at the Effecta Lamda). Look for the page with the graphs and you will get a sense for how far out you can stretch the Design curve (I believe you will be able to do this by setting the endpoints of your line). You can also get a sense of how low you might try running the temp. You will then be able to shift the line up or down as needed. This is how my ODR on my propane boiler works and based on the quick read I did of the Tarm I am pretty sure it works the same way. 
http://www.effecta.se/en/downloads?folder=Product+manuals


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## TCaldwell (Feb 20, 2017)

Congrats, you will see odr is pretty intuitive once you get up and running, keep us posted.


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## mark cline (Feb 23, 2017)

Just a thought here , my house is all in floor radiant .  Would an outdoor reset be able to control pump speed with a Grundfos variable speed pump? I will install hardwood flooring over my radiant tubing and don't want the water temp too high. I would like to keep the water temp. constant at about 110F.


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## Bad LP (Feb 23, 2017)

Are you using engineered flooring or solid? Remember RFH does not like to be covered up by a lot of wood or rug. I was taught not to go above 110. So that should be your high limit for the coldest of days days. I prefer my tile areas over my mahogany any day of the week. There is some really nice tiles being produced these days. Much more than 10 years ago when I built my house.

My mixing and ODR programing is done with a Taco radiant floor mixing block. The balance of the house is HWBB for now. My boiler is stupid.


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## velvetfoot (Feb 23, 2017)

Sparky said:


> Here is what I'm thinking, I set the design temp for the second floor baseboard, then the first floor with radiant will be a little hotter than needed, but will be tempered down by the manual tempering valve already installed in the system? I pretty sure I am going with the LK130 from Tarm it has the outdoor sensor and the indoor sensor. I think I have how I'm going to install it figured out, But as I stated before now if there is flow from my boiler and my house needs it it goes straight to the zones. But now I will always be running from and feeding storage? I believe I can install this so I can resort back to the way it is now. (if in design stage my house gets cold) I don't want Mrs. Sparky to get upset, she already thinks I have an obsession with my boiler



To me, it your plan sounds like the mix valve is modulating the temperature on a pipe at the top of the tank, normally based on flow out of the tank.  This pipe can see flow in both directions:  going into the tank when the boiler is running and going out of the tank when the tank is heating the house.  When the boiler is running in your setup, it seems that the zones would get first crack at the high temperature water coming out of the boiler, and then it would got to the normal outlet of the mix valve.  Then, since the temperature of the water where the ODR is sensing is so high (compared to what the ODR is specifying on its curve), all the hot water would get diverted around the tank and back to the boiler.  I think this is how the mix valve would work in reverse, no?  Then, the boiler would start to get too hot since the tank was unavailable to absorb excess heat.

It all depends on how it's piped up, I guess.  Maybe put the mix valve in a new parallel line and use check valves to control the flow direction?

I like the idea of using that same mix valve to meter how much heat is going into storage so you don't have such a cold return temperature to the boiler, and you're not robbing volume by  recircing it around the boiler via the protection valve.  I tried something similar but failed.

Another thought is that if the pump is running a lot you'll be using more electricity so you want efficiency there.


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## Chris Hoskin (Feb 23, 2017)

sorry, all, I haven't checked in for a couple of days.  Looks like everyone has this nailed down pretty well, thanks.  I guess if it was me, I'd use the LK130 to control supply temp to the radiant zone(s) only and leave the baseboard zones alone.  (yes, you would need two LK110/120/130 to supply two different supply temp needs). In peak heating season you will need as high a temp as you can get to the baseboards and in the shoulder seasons, where ODR becomes more important with high temp emitters, you are running off of storage more so you would tend to supply lower temps to the baseboard zone(s) by default anyway.  Great discussion, thanks guys.


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## Sparky (Feb 23, 2017)

That is what I am in the process of doing. I have baseboard on second floor and radiant on first. What I'm go to try to accomplish is setting the odr to second floor (water will be too hot for 1st floor. So I will temper that water w the manual value already in place. I will keep you posted to see how I make out. It's 3/4 installed now hopefully up and running by weekend I'm using the LK130 to do this


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## JohnDolz (Feb 23, 2017)

Chris Hoskin said:


> sorry, all, I haven't checked in for a couple of days.  Looks like everyone has this nailed down pretty well, thanks.  I guess if it was me, I'd use the LK130 to control supply temp to the radiant zone(s) only and leave the baseboard zones alone.  (yes, you would need two LK110/120/130 to supply two different supply temp needs). In peak heating season you will need as high a temp as you can get to the baseboards and in the shoulder seasons, where ODR becomes more important with high temp emitters, you are running off of storage more so you would tend to supply lower temps to the baseboard zone(s) by default anyway.  Great discussion, thanks guys.


Chris - I may have misunderstood what you were saying but I can tell you that I leverage my ODR all year long and run very low temp water through my "high temp emitters", even during "peak winter". Of course to make this work the zones are calling almost 24x7. As Velvetfoot points out, it takes electricy to do this but with the Alpha's + solar his is not something I factor in.


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## TCaldwell (Feb 24, 2017)

I have 5 zones of regular fin tube, one zone dual pipe fin tube and one radiant zone, all controlled by the same odr temp. The radiant is  controlled by a 3 way mix valve at the zone set to 120.  Basically all zones get the odr temp, however when that exceeds 120, the 3 way mix valve at the radiant zone acts as a high limit for that zone only. This seems to work well for me.


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## Sparky (Feb 26, 2017)

Well I couldn't pull it off this weekend. (Family over) Got the valve and the return line all cut in on Thursday filled it with water soldered on Friday 
Thought I was good.... Not I snuck down Saturday am to purge the line of air (I used the hot water from tank instead of building a fire)
Thankfully because I was almost complete and had a pin leak water spraying everywhere. 
I drained the system and where I had to solder the leak drip for 10 hours no matter what I did it wouldn't stop. Needless to say as of Saturday night all fixed, purged and a fire burning 
Monday after work I'll install rest of the components (pretty much plug and play)
With a few adjustments I should had ODR up and running thanks for everyone's help


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## TCaldwell (Feb 26, 2017)

You'll like the results!


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## JohnDolz (Feb 26, 2017)

Sparky said:


> Well I couldn't pull it off this weekend. (Family over) Got the valve and the return line all cut in on Thursday filled it with water soldered on Friday
> Thought I was good.... Not I snuck down Saturday am to purge the line of air (I used the hot water from tank instead of building a fire)
> Thankfully because I was almost complete and had a pin leak water spraying everywhere.
> I drained the system and where I had to solder the leak drip for 10 hours no matter what I did it wouldn't stop. Needless to say as of Saturday night all fixed, purged and a fire burning
> ...


Nice congrats. In fact Tom just finished putting the final modification (at least for this year) o my system. I believe we both now have a masters degree in the use of electric zone valves within a thermal storage system!


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## Sparky (Feb 27, 2017)

Well ODR is up and running the problem is my house is too warm from the sun and temperatures outside. So we will let it run thru the night and adjust tomorrow 


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## Dutchie84 (Mar 1, 2017)

How's it working now??


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## Sparky (Mar 1, 2017)

Not good I tapped into return line on wood boiler not on my house return loop so when my house was satisfied it kept pumping 130 deg water and I woke up at 2 am and it was 78 degrees in my house. I had to open windows to sleep so I will fix it and keep you posted thx


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## Sparky (Mar 4, 2017)

Well ODR is back online 
We will see how this works


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## velvetfoot (Mar 5, 2017)

Good luck!


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## JohnDolz (Mar 10, 2017)

Sparky said:


> Well ODR is back online
> We will see how this works
> 
> 
> Sent from my iPhone using Tapatalk


How's it working out? These wild temperature swings make it tricky to figure out the right points.


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## Sparky (Mar 10, 2017)

We will definitely know this weekend. It has been right on so far so I suspect these next few cold days it will be ok
Today I ran my tank down to 130 never had temps that low house was nice and warm gotta love it


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## JohnDolz (Mar 10, 2017)

Sparky said:


> We will definitely know this weekend. It has been right on so far so I suspect these next few cold days it will be ok
> Today I ran my tank down to 130 never had temps that low house was nice and warm gotta love it
> 
> 
> Sent from my iPhone using Tapatalk


Nice. I run my tanks below 120 sometimes. Depending on outside temps I end up throwing some extra wood in at some point to get me back up to the 180's/190's but it reduces the total # of fires I have to start (plus the greater efficiency reduces that even more). As I mentioned with my boiler I get to select a preprogrammed "curve" which controls the flow water temp based on outdoor temp. Last time we had a real winter I remember changing my curve when we moved from fall/winter to true winter and then again as we moved into spring/winter. Basically real winter needed a curve that produced slightly hotter water (I only changed the curve by 2 or 3 degrees). With the last 2 winters of crazy temp swings I have not even bothered, sometimes the house would get stuck at 68 for a few hours but then the sun would pop out or something would get me back to toasty 72.


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## TCaldwell (Mar 10, 2017)

Wait till the shoulder seasons, storage will last longer than you think


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## maple1 (Mar 11, 2017)

I think you can run your storage down as low without ODR as with. As long as your circs don't get cut off by a low temp setting in your controls, they should just keep circulating water as long as there is a call for heat - when temps bottom out, they will be circulating constantly at the same supply temp as the ODR would supply. The need for more heat should arise at the same storage temps. I don't have ODR and routinely run my storage down as low as possible - yesterday it was 120.


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## JohnDolz (Mar 11, 2017)

maple1 said:


> I think you can run your storage down as low without ODR as with. As long as your circs don't get cut off by a low temp setting in your controls, they should just keep circulating water as long as there is a call for heat - when temps bottom out, they will be circulating constantly at the same supply temp as the ODR would supply. The need for more heat should arise at the same storage temps. I don't have ODR and routinely run my storage down as low as possible - yesterday it was 120.


Keep in mind that I am a sales guy and not an engineer so I can tell you what I observe and think with no science behind it. What you say is correct but I believe the difference is that when you use ODR you can run for hours once your tank starts getting south of 150. When I did this without ODR I found that tank temp would "collapse" quickly and that my house would start getting cold. I believe the reason is that when set up with ODR (or more correctly to use constant circulation vs. the on/off) the house is never allowed to get cold (circulator turning off and then trying to recover). Basically using ODR and constant flow allows the system to "sip" at storage and SLOWLY house temp will drift down as design temp can no longer be fully reached. These are my observations running both ways in exactly the same system - like I said I have n science behind it but it is what I hve experienced. This allows me not be be sitting waiting for my tank to reach 150 so I can start another fire, I know I have several hours (maybe more, maybe less depending on outside temp) cushion before I need to start a fire. This is especially helpful when I travel, it allows my wife  much bigger window to start a fire.


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## Sparky (Mar 11, 2017)

All I know is before ODR I couldn't of satisfied my t-stat with a tank at 150 degrees. But now I can go to 130 and it works. I guess you could do it without ODR but it is the constant flow and the temps would be too high if your tank was at 180? It would satisfy the t-stat and you would be playing catch up? At least that's how I understand it. That constant flow of low temp water really has an effect on the load of your house. In a good way


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## JohnDolz (Mar 11, 2017)

Sparky said:


> All I know is before ODR I couldn't of satisfied my t-stat with a tank at 150 degrees. But now I can go to 130 and it works. I guess you could do it without ODR but it is the constant flow and the temps would be too high if your tank was at 180? It would satisfy the t-stat and you would be playing catch up? At least that's how I understand it. That constant flow of low temp water really has an effect on the load of your house. In a good way


I would agree but I am just a sales guy. For full disclosure I think I get $1 every time someone converts to using ODR. Glad it is working well for you.


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## Sparky (Mar 11, 2017)

You are doing great you should be able to retire soon!


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## maple1 (Mar 11, 2017)

Sparky said:


> All I know is before ODR I couldn't of satisfied my t-stat with a tank at 150 degrees. But now I can go to 130 and it works. I guess you could do it without ODR but it is the constant flow and the temps would be too high if your tank was at 180? It would satisfy the t-stat and you would be playing catch up? At least that's how I understand it. That constant flow of low temp water really has an effect on the load of your house. In a good way



Without ODR, with hotter water than needed, the circs just start & stop as demand is needed & met (think that's what is 'typical' of a traditional setup). Then as supply/storage temps drop, the circs run longer to meet the demand. That will get to a point where they would be running constantly to maintain house temp - then once supply/storage temps drop beyond a certain point, the house will lose temp even with circs running constant. That particular point, IMO, would be the same whether using ODR or not. ODR can't get more heat out of the same temp water - it just keeps a lower even supply temp all the time that will maintain house temp with constant flow. That is assuming that your circs will keep running as supply temps drop to what is still useful - and your emitters are capable of pulling the necessary heat out of the water & delivering to the house (which should be an 'all things equal' thing, as this is talking about supply temps & not involving any changes to emitters). If you are talking about some prior recovery situations, and maybe eliminating them, that might also be a factor since higher temps are usually needed for much recovery capability. But eliminating recovery situations by keeping your thermostats set constant would also eliminate recovery situations.


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## JohnDolz (Mar 11, 2017)

maple1 said:


> Without ODR, with hotter water than needed, the circs just start & stop as demand is needed & met (think that's what is 'typical' of a traditional setup). Then as supply/storage temps drop, the circs run longer to meet the demand. That will get to a point where they would be running constantly to maintain house temp - then once supply/storage temps drop beyond a certain point, the house will lose temp even with circs running constant. That particular point, IMO, would be the same whether using ODR or not. ODR can't get more heat out of the same temp water - it just keeps a lower even supply temp all the time that will maintain house temp with constant flow. That is assuming that your circs will keep running as supply temps drop to what is still useful - and your emitters are capable of pulling the necessary heat out of the water & delivering to the house (which should be an 'all things equal' thing, as this is talking about supply temps & not involving any changes to emitters). If you are talking about some prior recovery situations, and maybe eliminating them, that might also be a factor since higher temps are usually needed for much recovery capability. But eliminating recovery situations by keeping your thermostats set constant would also eliminate recovery situations.


You are correct but 2 points to consider: 1. When you have T-stats kicking on and off you are always dealing with recovery. As the water temp gets lower, the time the circs run will be longer but they will then shut off, temp will drop and then the need to recover. Regarding ODR getting more heat out of the same temp water, true but it can get better use out of the total # of BTU's stored. I use the analogy of a full tank of gas. It contains a certain amount of energy but the way you drive the car will impact the gas mileage that you get. Like I said I am not sure of all the math behind it but since I never drop into "Recovery mode" (other than at night - different conversation") I never feel drops in temp. Worst case is that my house VERY slowly and steady will cool of as the water flowing is slowly and consistently cooling. For example today, I have gotten buried in work and forgot about storage temp (started a fire late yesterday afternoon), it is now 20 degrees outside (was 10 at 6:00 AM. Design temp is 128, tank is at 130 but flow is actually at 125 - my house remains at 72. I could probably run this way for a few more hours as indoor temps very slowly drift down. When I ran with high temp water the t-stats would let the temp drop a bit and when the flow temp is low recovering becomes impossible. Regarding an emitters ability to extract heat, I have standard baseboard and put some aftermarket covers on them for esthetics - my plumber swears I lose at least 30% of the baseboards potential. In the shoulder seasons I see flow temp of 95 - 105 and my house still stays at 72.


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## TCaldwell (Mar 11, 2017)

Maple, you are correct, by eliminating the thermostat/zone cycling you are able to save a little heat in the tank at the end of the day, Tekmar has the numbers on that.
 We have had two weekends in a row for me that have not broken the single f degrees, and the wind chill at 15-22 below at night right now it's17 with a wc of 4 degf, I'm heating my house to 73deg with 129 deg water at a steady rate of 28kbtu/hr, 6 of my 8 alphas are running 20 watts or less. 
 Another observation, garn tank is at 173, outdoor mix temp is 129, my taco 007 is running at 35.7 pct output that's about 2.5 gpm to transfer 28kbtu/hr between the flat plate in garn barn to my supply header in the basement, approx 250 ft of piping. 
 Before, it took a 0014, at 9 gpm, sized for the worst day with higher flows to the zones to satisfy the thermostats a couple times per hr.
  This depicts two extremes but you get the idea.
  Overall I think it's a smoother operation, c'mon maple drink the koolaid !


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## Sparky (Mar 11, 2017)

I was going to respond but johndoltz couldn't have said it better. It works all I can say. I didn't change any radiation or didn't touch my radiant heat setting going this route is much easier on my storage 


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## JohnDolz (Mar 11, 2017)

TCaldwell said:


> Maple, you are correct, by eliminating the thermostat/zone cycling you are able to save a little heat in the tank at the end of the day, Tekmar has the numbers on that.
> We have had two weekends in a row for me that have not broken the single f degrees, and the wind chill at 15-22 below at night right now it's17 with a wc of 4 degf, I'm heating my house to 73deg with 129 deg water at a steady rate of 28kbtu/hr, 6 of my 8 alphas are running 20 watts or less.
> Another observation, garn tank is at 173, outdoor mix temp is 129, my taco 007 is running at 35.7 pct output that's about 2.5 gpm to transfer 28kbtu/hr between the flat plate in garn barn to my supply header in the basement, approx 250 ft of piping.
> Before, it took a 0014, at 9 gpm, sized for the worst day with higher flows to the zones to satisfy the thermostats a couple times per hr.
> ...


I knew someone would have the math! My parting comment as I need to pack to take my boys skiing is that I read somewhere that heating with low temperature water results in less (or maybe it was slower) heat rise which made it warmer down where we tend to spend most of our time resulting in less energy consumption. Can't swear to that one as I tend to stay closer to the floor than the ceiling.


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## velvetfoot (Mar 12, 2017)

I guess it's all about comfort.  I have my thermostats at .5 deg, which is not constant, like you constant flow guys, but it helps.  There are still slugs of cooled water in the emitter loop which have to be purged on every cycle with their time lags, and, in my case, the creaking during each heat-up.  Varying the temperature (and flow?) of the circulating fluid to maintain a constant house temperature  would seem to be the thing to aim for, and why would you need to know the outside temperature for that?


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## JohnDolz (Mar 12, 2017)

velvetfoot said:


> I guess it's all about comfort.  I have my thermostats at .5 deg, which is not constant, like you constant flow guys, but it helps.  There are still slugs of cooled water in the emitter loop which have to be purged on every cycle with their time lags, and, in my case, the creaking during each heat-up.  Varying the temperature (and flow?) of the circulating fluid to maintain a constant house temperature  would seem to be the thing to aim for, and why would you need to know the outside temperature for that?


If you are using some kind of mixing device to control the temperature of the circulating fluid, knowing the outside temperature allows the controller to set the ideal temperature of the circulating fluid to have you house reach the desired temperature. The goal is to use the flow temperature to get your room t the desired temp not the t-stat. Below are examples of the curve which determines my flow temperature. I get to choose the curve (move it up or down) and adjust it (I can move the right hand end point out while leaving the left hand end point in place.


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## velvetfoot (Mar 12, 2017)

Or....use a mixing valve or similar to vary the coolant temperature based on indoor temperature:  keep it constant...indoor temperature stabilizes with mix percentage at some point so that heat input = heat loss at the setpoint.  Setpoint changes, mix percentage and coolant temperature changes until it reaches some steady state at the new setpoint.  Would be better for setback recovery, plus you still have that constantly running pump you like.  

I think maybe the attraction of ODR is for fossil fuel boilers to minimize losses, ie to run it at a lower temperature.  With a tank, what you have is what you have-it has a certain amount of BTU's in it at any one point in time.  You can use it in different ways  for different emitters at the same time, as in fast setback recovery in baseboard, and maybe not so great a delta for radiant.

I wouldn't know where to buy this stuff though...I just dreamed it up, lol


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## Dutchie84 (Mar 13, 2017)

JohnDolz said:


> If you are using some kind of mixing device to control the temperature of the circulating fluid, knowing the outside temperature allows the controller to set the ideal temperature of the circulating fluid to have you house reach the desired temperature. The goal is to use the flow temperature to get your room t the desired temp not the t-stat. Below are examples of the curve which determines my flow temperature. I get to choose the curve (move it up or down) and adjust it (I can move the right hand end point out while leaving the left hand end point in place.
> 
> View attachment 195927


John, why would you have to change your curve for the time of year?  Your emitter size didn't change, the insulation levels in your house didn't change, so your house's heat loss per degree F from inside temp to outside would be the same all year.  Isn't that what ODR is for?


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## JohnDolz (Mar 13, 2017)

Dutchie84 said:


> John, why would you have to change your curve for the time of year?  Your emitter size didn't change, the insulation levels in your house didn't change, so your house's heat loss per degree F from inside temp to outside would be the same all year.  Isn't that what ODR is for?


I find that the curve I can use in the should season doesn't quite do it when it get really cold. I could choose a curve that meets my winter needs and leave it there but in the shoulder seasons it produces flow temp just a little hotter than I need (circs end up going on and off). Now that I think about it, I could probably play with the adjustment feature and maybe get to where I need. I have taken the lazy way and just tweak the curve once or twice a year (it literally takes 2 seconds).


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## JohnDolz (Mar 13, 2017)

velvetfoot said:


> Or....use a mixing valve or similar to vary the coolant temperature based on indoor temperature:  keep it constant...indoor temperature stabilizes with mix percentage at some point so that heat input = heat loss at the setpoint.  Setpoint changes, mix percentage and coolant temperature changes until it reaches some steady state at the new setpoint.  Would be better for setback recovery, plus you still have that constantly running pump you like.
> 
> I think maybe the attraction of ODR is for fossil fuel boilers to minimize losses, ie to run it at a lower temperature.  With a tank, what you have is what you have-it has a certain amount of BTU's in it at any one point in time.  You can use it in different ways  for different emitters at the same time, as in fast setback recovery in baseboard, and maybe not so great a delta for radiant.
> 
> I wouldn't know where to buy this stuff though...I just dreamed it up, lol


You are over my head sir. I can only tell you that if you believe the concept of pulling as little hot water as possible from storage equals the most efficient use of stored BTU's the having ODR pick the lowest possible design temp to meet the need is the reason. You are correct on Recovery, I do not know how Sparky's ODR address it but with the Effecta I also have an Indoor sensor. This sensor keeps an eye on actual indoor temp vs are temp. When it is time for my Recovery to begin, this sensors sees that actual is wll below target so it overrides ODR. It then uses the Outdoor Temp and the delta of actual vs. target indoor temp and i chooses a desired design temp. As Indoor Temp approaches target this control is constantly adjusting flow temp until it finally gives control back to ODR.  I know Mr. Caldwell's leverages inside temp as well as the Outdoor temp.


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## maple1 (Mar 13, 2017)

I think I have been here before. Maybe this time last year. 

I have no doubt ODR gives a more constant smoother even heating operation through the complete range of storage supply temps, but I will still stick with my feelings that it won't extend your storage capacity or let you go longer between burns or run storage lower - all else being equal. At the bottom storage temps (as storage nears depletion), they are both doing the same - circulating the same lower temp water, constantly, until the house starts losing temp & you need to recharge.

That's my story & I'm sticking to it.


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## nhtreehouse (Mar 13, 2017)

Dutchie84 said:


> John, why would you have to change your curve for the time of year? Your emitter size didn't change, the insulation levels in your house didn't change, so your house's heat loss per degree F from inside temp to outside would be the same all year. Isn't that what ODR is for?



Very interesting discussion here...

While I don't have a boiler at the moment, I'm in the research phase and ODR is a very interesting aspect. What I think is really cool about the forum is we have all sorts of users reporting their actual experience which other members can then offer other insight into, and in the end, we all learn something.

So, on moving the reset curve based on season... In theory, you shouldn't have to. But it's important to remember that ODR is a first order correction. By that term, I mean that it provides a prediction of the correct supply temp to the emitters based on knowledge of the outside and (optionally) inside temperature.

What happens on days when the wind blows the "oysters off the rocks?" Well, the heat loss of the building increases and the circs will flow 100% of the time and not keep up. Or conversely, if the building has high external gain, from, say solar radiation, the circs will throttle down the heat distribution from the emitters to prevent overheating.

So I suspect JohnDolz's heating system has some external loss during mid winter which is not present in the shoulder seasons. Or, it would be just as valid to say that his system has more external gain during the shoulder seasons than in mid winter. Potato, Potatoe...

My 2 cents...


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## nhtreehouse (Mar 13, 2017)

maple1 said:


> I think I have been here before. Maybe this time last year.
> 
> I have no doubt ODR gives a more constant smoother even heating operation through the complete range of storage supply temps, but I will still stick with my feelings that it won't extend your storage capacity or let you go longer between burns or run storage lower - all else being equal. At the bottom storage temps (as storage nears depletion), they are both doing the same - circulating the same lower temp water, constantly, until the house starts losing temp & you need to recharge.
> 
> That's my story & I'm sticking to it.



Hey Maple,

That was what I was thinking when I first read Sparky's and JohnDolz's posts to the effect that ODR gives longer run time from storage. But I got to thinking about it and I believe there may be some second order effects which are not at all obvious. I'll throw out a couple of theoreticals which support the ability to run longer from storage when mixing down the tank supply with ODR:


While I agree 100% that the energy in water is a fixed and calculate-able number, it's the available energy to the supply system which we are trying to figure out. Themo-heads would call this Exergy, and it is most definitely not equal to the energy in the tank. The Biomass Training sticky has some discussion on this.
On Exergy, it seems to me that mixing down the tank actually increases the available energy in the tank. The reason why is the flow through the tank supply/return ports is lower using ODR than with a straight supply from the tank to the system plumbing. The reason why is system flow is made up of system return flow and supply from the tank. As we are turning over the tank less, stratification is promoted, Exergy is higher.
Loss in system piping is less as the heat loss from system supply piping is proportional to some delta-T. Now, you can argue that all system piping loss is inside the building envelope, and there is some merit to that. It all depends on the system piping. If that piping is inside conditioned space, then, yes, this is the case. As soon as you put a supply pipe in a wall, that pipe looses heat both to the outside and inside the building envelope. It gets complicated.
The last and quite hard to quantify effect might be that the heat emitters work more efficiently with constant flow. No experience here, but obviusly if the emitters are more efficient, then the effective Exergy of the system increases.
I'm planning my system to have storage in an outside building. Mixing down system supply in that building before shoving it over to the house in underground pex will certainly lower the system piping loss.

On running with a lower supply temp at the end of the storage interval, I am truly stumped. Maybe I need to get my "I violate the laws of physics" card punched? 

Everything in this post is strictly theoretical and as always, your mileage may vary...


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## Dutchie84 (Mar 13, 2017)

nhtreehouse said:


> Hey Maple,
> 
> That was what I was thinking when I first read Sparky's an JohnDolz's posts to the effect that ODR gives longer run time from storage. But I got to thinking about it and I believe there may be some second order effects which are not at all obvious. I'll throw out a couple of theoreticals which support the ability to run longer from storage when mixing down the tank supply with ODR:
> 
> ...



Tree house. When are you planning on doing you system?  I am planning a similar system in my new house. I hope you will keep us up to date with lots of pictures [emoji6]


Sent from my iPhone using Tapatalk


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## nhtreehouse (Mar 14, 2017)

Hey Dutchie,

Assuming a fair and following wind, this year sometime. With the amount of work I have to do just to prep for the install, it's going to be a miracle if I'm firing next winter. We shall see!


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