Everything Drolet Tundra - Heatmax...

[3fordasho]

I have seen on this forum where you guys have added controllers for the fan and damper, I have to look thru the posts again to find exactly what controllers were used and how they are wired in, I told SBI that I shouldn’t have to do all that but if it makes these Tundras work better and you guys seem to be a lot happier after it’s done then I guess I’m on board doing it

The factory controls are rudimentary at best. Yes there is a high limit, but things get pretty hot before that trips, (see cracked metal around the loading door) and it's pretty easy to have a smoldering fire and the damper will never open unless the thermostat calls for heat. A few of my first fires with factory controls actually had water dripping out the bottom of the flue connection. Also in my case (too large a house for furnace) the thermostat would probably never be satisfied resulting in the air inlet being open the entire time, very hot furnace tripping the high limit multiple times and lots of cracks around the loading door.

Other modifications are for convenience - the timer allows you to throw a load of wood in, set the timer and leave. Otherwise you have to use the manual switch and stick around until the new load is charred adequately and then manually turn it off.

The flue temp control does two things, first a safety feature - the set point is set up to close the air inlet at the highest point you want to see your flue temps. In my case that is 625F. So when the thermostat calls for heat for an extended period, or the timer is set too long, or the factory air inlet switch is accidently left on, the temp control shuts it down at 625F. The factory limit switch is still there and functional as a back up.

The second thing it does is open the air inlet if flue temps drop too low, in my case that is 275F. So say you start a new load of questionable wood (slightly wet) and think you got it charred enough so it will continue with secondary burn, but if flames out and just sits there and smolders - now you have little heat and are making creosote in the chimney, now is when the temp controls opens the air inlet and gets things in a proper temp range again. It also does great at burning down coals at the end of the burn cycle.

The blower speed control helps get more heat out of a load by ending the on/off cycling that lets heat go up the flue during the off part of the cycle.

 

[Matt78]

The factory controls are rudimentary at best. Yes there is a high limit, but things get pretty hot before that trips, (see cracked metal around the loading door) and it's pretty easy to have a smoldering fire and the damper will never open unless the thermostat calls for heat. A few of my first fires with factory controls actually had water dripping out the bottom of the flue connection. Also in my case (to large a house for furnace) the thermostat would probable never be satisfied resulting in the air inlet being open the entire time, very hot furnace tripping the high limit multiple times and lots of cracks around the loading door.

Other modifications are for convenience - the timer allows you to throw a load of wood in, set the timer and leave. Otherwise you have to use the manual switch and stick around until the new load is charred adequately and then manually turn it off.

The flue temp control does two things, first a safety feature - the set point is set up to close the air inlet at the highest point you want to see your flue temps. In my case that is 625F. So when the thermostat calls for heat for an extended period, or the timer is set to long, or the factory air inlet switch is accidently left on, the temp control shuts it down at 625F. The factory limit switch is still there and functional as a back up.

The second thing it does is open the air inlet if flue temps drop too low, in my case that is 275F. So say you start a new load of questionable wood (slightly wet) and think you got it charred enough so it will continue with secondary burn, but if flames out and just sits there and smolders - now you have little heat and are making creosote in the chimney, now is when the temp controls opens the air inlet and gets things in a proper temp range again. It also does great at burning down coals at the end of the burn cycle.

The blower speed control helps get more heat out of a load by ending the on/off cycling that lets heat go up the flue during the off part of the cycle.

As Ron Popeil said "set it and forget it" I wouldn't want to run furnace without the temp control

 

[brenndatomu]

It's not just the Tundra's which work better with a variable speed blower controller, pretty much ALL solid fuel burning furnaces can benefit from one.

AMEN BROTHAH HAWK!

 

[smw]

Well its seems that I will definitely look in to getting my stove to the "set it and forget it" spot lol, I like that!! I seen on @3fordasho post I believe he used an Omega temp controller and a Mcmaster thermocouple and I have been looking for those or if there is an equivalent. I got my anti back draft damper installed in the propane furnace yesterday and I am going to burn those bricks from Menards today and see how everything goes. I also plan on doing my fresh air intake from a window tomorrow or Monday and I also have to get my static pressure up. Right now I'm about .15, the manual says .2 and the guy at SBI said anywhere from .2-.5 but if I could get it to .4 it would be perfect. I have googled how to change static pressure but can't really find an answer. I have my stove going into my duct work that the propane furnace uses, I didn't go into the plenum, I went into 2 separate locations in the duct work itself with 8" pipes. I have my cold air using the air from the basement and we also leave the basement door open. I again want to thank everyone in here for their help and all the knowledge that is in here!! I hope everyone has a Merry Christmas!!

 

[brenndatomu]

Well its seems that I will definitely look in to getting my stove to the "set it and forget it" spot lol, I like that!! I seen on @3fordasho post I believe he used an Omega temp controller and a Mcmaster thermocouple and I have been looking for those or if there is an equivalent. I got my anti back draft damper installed in the propane furnace yesterday and I am going to burn those bricks from Menards today and see how everything goes. I also plan on doing my fresh air intake from a window tomorrow or Monday and I also have to get my static pressure up. Right now I'm about .15, the manual says .2 and the guy at SBI said anywhere from .2-.5 but if I could get it to .4 it would be perfect. I have googled how to change static pressure but can't really find an answer. I have my stove going into my duct work that the propane furnace uses, I didn't go into the plenum, I went into 2 separate locations in the duct work itself with 8" pipes. I have my cold air using the air from the basement and we also leave the basement door open. I again want to thank everyone in here for their help and all the knowledge that is in here!! I hope everyone has a Merry Christmas!!

Everything you want to know is in this thread somewhere's.
Static pressure is just backpressure on the blower. I wouldn't worry about it too much...I pay more attention to temp rise through the furnace...get the most temp rise you can and still move the heat to the house, without the blower cycling off/on too much...and you can just about ignore SP and temp rise once you put a speed controller on...it will just hold the blower speed to maintain its target temp...works perfect.
Many of us are using Mypin brand temp controllers, with good success as far as I know...and I have some random generic TC that fit the bill for me.

 

[Highbeam]

It’s discouraging for those of us that might want to move to a furnace to think that we have to become parts chasing electrical engineers just to get these furnaces to function safely and efficiently. It’s not a cost issue if even the kuumas need these upgrades.

 

[brenndatomu]

It’s not a cost issue if even the kuumas need these upgrades.

I don't know that the Kuuma needs this upgrade, but for someone like @JRHAWK9 that is heating a house that is approaching the capabilities of the VF100, the blower speed controller just adds a bit more output and efficiency.
As for Tundra...yep, parts chasing engineer
At least you have something that works good when you are done

 

[Highbeam]

I understand optimization, hot rodding, upgrading, etc. but can these furnaces be run as designed by the factory? Are they junk and/or dangerous out of the box? For the benefit of the regular people, I would hope that the dang things just work safely!

 

[brenndatomu]

I understand optimization, hot rodding, upgrading, etc. but can these furnaces be run as designed by the factory? Are they junk and/or dangerous out of the box? For the benefit of the regular people, I would hope that the dang things just work safely!

You are talking about the Tundras? If so keep in mind they have moved on to the T2 now...haven't heard anybody complain about one of those yet.
Dangerous? Not in my opinion...the only thing "dangerous" that I can think of was when they had the ash pan recall early on...I would think those should all be weeded out by now.
I think the biggest issue with them is that SBI overated them...I think a person with a house on the lower end of their rating scale would be the happiest with a stock Tundra...still talking T1 here...need more input on the T2s to form an opinion on those yet.

 

[3fordasho]

I understand optimization, hot rodding, upgrading, etc. but can these furnaces be run as designed by the factory? Are they junk and/or dangerous out of the box? For the benefit of the regular people, I would hope that the dang things just work safely!

I think the Tundras are fairly safe right off the crate, certainly better than some of the pre-EPA offerings very recently still available (think Hot Blast with its stick wide open air inlet). The Tundra does have a high limit and will close air in the event of power failure. I personally get nervous when flue temps get much over 800f, which I've seen on my Tundra when I left the air inlet switch on too long - the factory high limit will shut it down eventually, but not soon enough in my opinion. Possibly the reason the early ones cracked. It's probably still very safe, especially if you've maintained your flue.

My preference is to have additional controls to make sure I can't overheat things when I forget to shut off the air inlet switch, or maybe let that next chimney cleaning slide a little too long and now that unintentionally overheated flue touches off some build up..

Maybe it's a irrational fear but it comes from having a cat stove with a bypass that lets flames shoot right up the flue... it was more than a time or two that just a few minutes too long in bypass resulted in a pegged flue temp probe (1000F+) and really hot smelling connector pipes.

Most of the other mods are for convenience or to extract a bit more heat or efficiency because some of us should have bought a bigger furnace to start with...

 

[sloeffle]

Earlier this year I bought a fan speed controller and MyPIN for my Caddy. With help from @brenndatomu I was able to get the MyPIN and timer up and working. Livestock and life got in the way of getting the fan speed controller hooked up. I had to burn some vacation this past week , so I decided to hook my fan speed controller up. I must say, that thing works pretty slick. Not hearing the fan kick off and on constantly at the end of a burn will be great.

I used the ICM326HN head pressure unit ( you can find it on fleabay a lot cheaper ) from ICM since you do not need a 24V transformer. I was also able to find "newer" versions of the unit for the same price as older Totaline units.

 

[brenndatomu]

I don't recall now which model it was, and if it was ICM, Totaline, or both, but there is one model that has its own built in 24V power supply.
I've noticed that since I've posted about using these speed controllers this way, the prices of them on the fleabay has went up some...

 

[smw]

https://www.amazon.com/dp/B00X5EZXV4/?tag=hearthamazon-20

Here is the controller I’m looking at getting, I haven’t figured out how to post pictures yet.

 

[JRHAWK9]

Are they junk and/or dangerous out of the box?

not in the least. The Kuuma is UL listed and rated for gravity heat flow if the power should ever go out. It has a high limit switch to protect against excessive plenum temps and the computer has an audible and visual firebox over-temp alarm to alert in case of higher than normal -firebox- temps. IE if the draft is too high or the ashpan door is ever left open. This alarm is not a "critical point" type of alarm, it's more of a, "hey firebox temps are a bit higher than normal, please check things out" type of alarm.

I optimize everything I own for the situation it's being used in. I get told time and time again how I just can't leave things alone. My wood splitter, chainsaws, snow blowers, cars, computers, etc all are not like they came from the factory and all have some level of mods done to them. Why would I not do the same for something heating our home? As far as wood furnaces go, you are transferring heat via air. Every house is different. What blower setup works for me may not work for someone else so it's impossible for any manufacturer to dial in the setup optimally for all situations.

 

[Highbeam]

not in the least. The Kuuma is UL listed and rated for gravity heat flow if the power should ever go out. It has a high limit switch to protect against excessive plenum temps and the computer has an audible and visual firebox over-temp alarm to alert in case of higher than normal -firebox- temps. IE if the draft is too high or the ashpan door is ever left open. This alarm is not a "critical point" type of alarm, it's more of a, "hey firebox temps are a bit higher than normal, please check things out" type of alarm.

I optimize everything I own for the situation it's being used in. I get told time and time again how I just can't leave things alone. My wood splitter, chainsaws, snow blowers, cars, computers, etc all are not like they came from the factory and all have some level of mods done to them. Why would I not do the same for something heating our home? As far as wood furnaces go, you are transferring heat via air. Every house is different. What blower setup works for me may not work for someone else so it's impossible for any manufacturer to dial in the setup optimally for all situations.

Understood. I was asking about whether the modifications spread out over nearly 100 pages of this thread are required or optional. See, a guy that just wants a dang furnace might think he can’t have one without making these changes, upgrades, etc. and still enjoy reasonable safety, efficiency, and durability.

 

[brenndatomu]

Understood. I was asking about whether the modifications spread out over nearly 100 pages of this thread are required or optional. See, a guy that just wants a dang furnace might think he can’t have one without making these changes, upgrades, etc. and still enjoy reasonable safety, efficiency, and durability.

I don't think anybody can expect to buy a wood furnace, hook it to a chimney, connect the ducts, light it and be done...if anybody has, they just got lucky IMO...I think that almost all of them require some setup work to be optimized...and some more than others obviously...Kuuma would probably be the one that I would guess would take the least amount of work...normally anyways...

 

[sloeffle]

Understood. I was asking about whether the modifications spread out over nearly 100 pages of this thread are required or optional. See, a guy that just wants a dang furnace might think he can’t have one without making these changes, upgrades, etc. and still enjoy reasonable safety, efficiency, and durability.

I paid an HVAC company to install my wood and geothermal furnaces and within a week or two I was replacing some of the stuff they put in with better stuff. I didn’t want to have to manually move a damper when I was using my wood furnace so I put a 24V power damper in.

I ran my Caddy for 5 years without making a single modification to it. It ran fine, but a hundred dollars or so later, and a little bit of time it is easier to use and seems to run a little better. I think it is people’s nature to modify things to make them better for their application. Look at the billions ( yes, billions ) people spend on aftermarket car parts. I look at it and think, what a waste of money but a lot of other people think differently. To each his own I guess.

 

[brenndatomu]

so I decided to hook my fan speed controller up. I must say, that thing works pretty slick

By the end of January (or before) you'll be in love...

 

[laynes69]

So after seeing all of these blower control mods, I went back and re-evaluated my system. Fortunately, I have a 2 speed limit control that came from the factory. Unfortunately it does not shut off (designed to run constant), however will operate a high and low blower speed. I just need to figure out where to set the controller. I do have a second limit control I could use to shut off the low blower, or just a simple snapdisc correct? I'm going to try the 2 speed blower and see how it does.

 

[brenndatomu]

So after seeing all of these blower control mods, I went back and re-evaluated my system. Fortunately, I have a 2 speed limit control that came from the factory. Unfortunately it does not shut off (designed to run constant), however will operate a high and low blower speed. I just need to figure out where to set the controller. I do have a second limit control I could use to shut off the low blower, or just a simple snapdisc correct? I'm going to try the 2 speed blower and see how it does.

Boy, I don't know if you are going to be too happy with that...might not make much difference IMO.
For me, the big win with the variable speed control was
1. The ability to wire to the high speed tap so that when the fire is rippin hot, the blower can take advantage of it.
2. When the fire is down to just a few coals, the blower runs real slow for hours...non stop...so you are stripping heat from the flue gasses all the time instead of waiting for the blower switch to get hot enough to turn things back on for a minute or two....I think this was the biggest part of the gains for me...
(now, that said, don't turn the speed down too far or you could burn out the motor since it can't cool itself...especially since most of these motors are sleeve bearing and not ball bearing. Even with the sleeve bearing settings the blower is running pretty dang slow...I have checked mine countless times after it has run on low for extended periods and found it barely even warm...I'd say even cooler that where it would be normally...but that's JMO)

 

[laynes69]

I have been running speed 2 this year, and I set speed 1 for the low. Right now it's set to run at speed 2 then go to speed 1 when it hits 100 or below. I just don't know if there will be enough heat to bring it back up during the coaling stage though? This will capture heat during the coaling stage when the blower normally wouldn't run at the end. I have 2 speed taps on the limit control (not including the high limit), with the temperature settings to go to high, then drop to low again.

 

[sloeffle]

I have been running speed 2 this year, and I set speed 1 for the low. Right now it's set to run at speed 2 then go to speed 1 when it hits 100 or below. I just don't know if there will be enough heat to bring it back up during the coaling stage though? This will capture heat during the coaling stage when the blower normally wouldn't run at the end. I have 2 speed taps on the limit control (not including the high limit), with the temperature settings to go to high, then drop to low again.

@laynes69 my Caddy has a two speed fan limit switch. The low speed on the fan limit switch is wired into a summer switch. It is a simple switch that is on metal box that fan limit switch is wired into. I had the summer switch running my low speed fan. I would use it during the coaling stage but I would have manually turn it on. You could leave the switch on all of the time but sometimes I would forget to turn it off. I didn’t like leaving it on at night either because the fan would run all night then too. I also use fan speed 2. Anything above fan speed 2 creates too much static pressure in my plenum.

IMHO the timer and blower mod are well worth the time and money. The blower mod is nice because it is all automatic. You don’t have to worry about turning a switch on or trying to explain to someone what to do. The timer is nice because you can just load any go. My wife even doesn’t mind loading the furnace now.

Edit: If you ever in this part of the state give me a shout. I’d be happy to show you my setup. I am about 45 minutes south of you.

 

[smw]

Well I ordered the MYPIN TA6 controller, the Totaline P251-0083H speed controller for the blower and I have my hot tub timer. I should have everything for Friday and then I can hopefully hook it up Friday or Saturday and let the good times roll lol. I now have to search this thread for wiring diagrams and directions how to hook everything up. I already printed one off but that was for an Omgea controller so I'm not sure if it will be the same, I don't have much knowledge in this technical stuff. Update on my furnace not burning good is this. I installed a fresh air intake from outside but idt it really made any difference, I burned those compressed wood bricks from Menards and they burned good and hot and had some secondary burn but it didn't last very long, maybe 30 mins for the secondary burn, I'm going to have to dig thru my wood pile for the ash and leave the oak for now. I haven't changed the blower speed from 3 to 2 yet, I will probably do that tonight.

 

[NateJD]

I've got a question I feel stupid asking since I don't know anything about temp controls and such. I've been burning the Tundra for 3 years. I've had the firebrick update installed since the beginning and never had cracking issues. I've been reading about temp controls for the damper and they don't really interest me, I actually like running the furnace from my thermostat. What I would really like to do is control the fan based on flu temp or plenum temp. My propane only kicks on during the end of the burn when the stupid fan is cycling on and off. Seems I still get good heat when the fan is on and it's wasted when off. Instead of running the fan like a variable speed motor, could you run it through some controller that changed to speed 1, 2, 3, or 4 based on temp? Would it be better to get that temp signal from the flu or the plenum. Any pro, cons, or thoughts on this?

 

[brenndatomu]

Instead of running the fan like a variable speed motor, could you run it through some controller that changed to speed 1, 2, 3, or 4 based on temp? Would it be better to get that temp signal from the flu or the plenum. Any pro, cons, or thoughts on this?

It has been done both ways...I personally don't like the speed 1, 2, 3, 4 method because the fan still moves a lot of air on low speed and you will still get the cycling on/off...the speed control that we have been using can keep the blower running at a very low speed for hours on end at the end of the burn...it made a huge difference for me.
You want to take the temp reading from the plenum IMO.