How About a Clamp On Ultrasonic Flow Meter for $400?

[velvetfoot]

Without reset, the buffer tank will never be going below the boiler aquastat on temp as long as fuel is available

I was thinking of the buffer tank acting as a "boiler". If there is a call for heat, circulators will run, drawing water from the tank until a certain tank temperature is reached-something less than 175, let's say 140, measured near the top of the hopefully stratified tank, at which point the boiler would start up and recharge the tank and at the same time,any zones still calling for heat. I can imagine an issue that there could be a point on a cold day when 140 wouldn't be enough and the zones started cooling despite pumps being on. Since this is 120 gallons vs 1000 gallons there wouldn't be that long a wait until the boiler goes on again and starts heating things up again- maybe 3780 btus=108 gal * 35delta T. Perhaps in my "boiler" scenario, the pellet and oil boilers could be designated by the thermostat as second and third stage heat. Or, if the output of the "boiler" was mixed to the ODR curve, you'd be trusting the ODR curve and your goal would be a constant temperature and constant run times of the circulators until that couldn't be supported and a call for heat sent. Maybe that's not the ultimate way to get the fewest starts and stops of the pellet boiler. Just thinking out loud.

 

[velvetfoot]

dan, I didn't see your photo.

I want to continue to use my wood insert some, if for no other reason than to draw down my wood storage. Therefore, the boiler could be operating at reduced load, so I though a buffer tank would help with this, lowering the number of boiler starts and stops.

 

[__dan]

Out for the day, will have an interesting reply for you later.

 

[ewdudley]

If there is a call for heat, circulators will run, drawing water from the tank until a certain tank temperature is reached-something less than 175, let's say 140, measured near the top of the hopefully stratified tank, at which point the boiler would start up and recharge the tank and at the same time,any zones still calling for heat.

I thought the Windhagers were designed for modulated constant burn down to about 30% of maximum firing rate, specifically to avoid on-off cycles. If this is the case I would think you would need only a smallish buffer to even out whatever loading intermittency the baseboard loads might cause, which would allow the boiler to run continuously without cutting out on high limit.

 

[ewdudley]

In the future the VS circs will be ECM , as ECM is ideal for VS, but they are not on the market yet AFAIK.

What circulator manufacturer doesn't market a VS ECM circ?

 

[BoilerMan]

I have one Alpha pump, and 5 zone valves. Each zone valve has ball valves on either side for easier replacement. I've got all the ball valves set about half way closed, and the Alpha on lowest dP setting - even though I know it's not recommeneded to throttle flow with ball valves, there's not a lot of flow going through with the pump on low. I've got them set to not quite closed enough to create any noise. That was done to try to get my return temps as low as I could, as easily as I could. I also have temp guages here I haven't got installed yet, one will be on system supply & one on system return. I could use those guages to tune in my ball valves further, trying to get to a certain dT in each zone, if my interest holds long enough - I've got all kinds of 'almost done' projects lying around here...

Sounds like the Dt Bumble Bee would work well in this application.

TS

 

[__dan]

What circulator manufacturer doesn't market a VS ECM circ?

VS circ with an OAT reset controller, I was referring to. Not on the market yet AFAIK. The reset controller does VS injection pumping with a standard taco 007 PSC wet rotor and will not mate up to an ECM circ. It will in the future however as ECM circs are made for VS.

 

[__dan]

I was thinking of the buffer tank acting as a "boiler". If there is a call for heat, circulators will run, drawing water from the tank until a certain tank temperature is reached-something less than 175, let's say 140, measured near the top of the hopefully stratified tank, at which point the boiler would start up and recharge the tank and at the same time,any zones still calling for heat. I can imagine an issue that there could be a point on a cold day when 140 wouldn't be enough and the zones started cooling despite pumps being on. Since this is 120 gallons vs 1000 gallons there wouldn't be that long a wait until the boiler goes on again and starts heating things up again- maybe 3780 btus=108 gal * 35delta T. Perhaps in my "boiler" scenario, the pellet and oil boilers could be designated by the thermostat as second and third stage heat. Or, if the output of the "boiler" was mixed to the ODR curve, you'd be trusting the ODR curve and your goal would be a constant temperature and constant run times of the circulators until that couldn't be supported and a call for heat sent. Maybe that's not the ultimate way to get the fewest starts and stops of the pellet boiler. Just thinking out loud.

No.

Assuming no oil for the moment, two house baseboard zones on zone valves, indirect DHW, the Biowin and the buffer tank: OAT reset scenario:

The house zone thermostats call the zone valves and the zone valves end switch calls the Tekmar reset injection pump comtroller. The reset controller starts the system circ (the Alpha) and the mix demand is calculated, starting the VS injection pump. It will do a trial run and if the header (the buffer tank) the VS circ draws from cannot make the mix demand temp, the reset controller will call the Biowin to fire.

In this scenario I do not see using the boiler return protection feature at this time because the loads are returning to the buffer tank and not the boiler, at a low temp. Return at the boiler is tempered with supply water, but you have to enable the injection pump to get the system to run, and drawing from the buffer tank, boiler return will be cold.

If Windhager rates the Biowin to run without a buffer tank, this is the scenario that would work without the buffer tank. There would be a way to bypass the load circs, zone valves, and use them as a dump zone for the boiler off cycle.

This is a sequence of operation, not a wiring diagram. There are a few things necessary to get everything working, which a controls person would do, based on the final design implementation.

It is not a constant flow system, but you can tweak the reset slope in that direction. Heat is called or not by the inside stats but the reset controller sets loop water supply temp to the demand, which is based on the OAT. The load is on longer at a lower HWS temp and the Biowin has a chance to modulate down and match output to the load..

 

[__dan]

dan, I didn't see your photo.

Post #2 in your thread. Click on the links for the photos.

https://www.hearth.com/talk/threads/how-does-the-constant-flow-thing-work.126690/

post #144 and #145 in this thread

https://www.hearth.com/talk/threads/a-few-pictures-of-our-boiler-systems.75006/page-6

 

[ewdudley]

VS circ with an OAT reset controller, I was referring to. Not on the market yet AFAIK. The reset controller does VS injection pumping with a standard taco 007 PSC wet rotor and will not mate up to an ECM circ. It will in the future however as ECM circs are made for VS.

Nothing turnkey. Grundfos UPM2 series with 0-10 vdc or PWM input and an off the shelf outdoor reset controller like a TC204 would do it.

 

[__dan]

Nothing turnkey. Grundfos UPM2 series with 0-10 vdc or PWM input and an off the shelf outdoor reset controller like a TC204 would do it.

ECM will have far better performance than PSC motor at VS, they are ideal for it. They are just new and the market is not mature for every application yet.

The control I was thinking of does not offer the 0 to 10 V output but does power the Taco 007 directly.

If using the buffer tank, it may be possible to draw for the injection pump from the top of tank and return to bottom, using the tank as the hydraulic separator. The injection pump will have very low flow at the maintenance temp and maybe some stratification and heat scavenging from the tank. The tank will not be doing nothing but it may be possible to omit the buffer tank and draw from the boiler primary loop with closely spaced tees as shown in the diagram.. I don't see how OAT reset may be omitted from the implementation.

Even the buffer tank may not replace the functionality of the reset scenario.

plumbing and wiring diagrams.

http://tekmarcontrols.com/images/_literature/361_a_06.pdf

 

[heaterman]

I would absolutely forget about the electricity cost of the circ running longer as it is such a small number. However, if you can reduce start stop cycles of the Biowin by half monthly, by operating the boiler in its modulating range, it should be burning cleaner with less maintenance required and better overall satisfaction.

This is what you want to shoot for.

Basically, I have found that a system which generates instant on/off loads is best served with a buffer tank of 50-80 gallons.
If however, the system can generate long pulls on the heat demand such as a thick slab radiant floor or a modulating load like TRV's or injection mixing, The Windhager is in it's element....doing what it was designed to do. Modulate to meet demand.

It would be a dis-service to the boiler to connect it to a system which can generate small, instant on-off demand. You want to hit a minimum of and hour per cycle. Your target should be 2 hours per start cycle for satisfactory equipment life/performance and efficiency.
This is true of any boiler capable of modulating its output.

My house heating system has no "thermostat" in the conventional sense of the word. Just TRV's on panel radiators and a motorized mix valve running the water temp to the radiant floor areas. The mix valve varies water temp to the floors based on the outdoor temp and the TRV's throttle the flow to each of the 5 panel rads according to where they are set.
This creates variable demand and the BioWin responds just as it should, ramping up and down to keep up with what is going on in the house.
Many times I'll see the boiler sitting at 40% or less output level as it maintains the whatever setpoint I have dialed in at the moment. It's a beautiful thing.

 

[velvetfoot]

Here is a Tarm conceptual diagram I found. Looks like some mixing going on. I still wonder how it'll work without.

 

[__dan]

Velvet, the diagram you posted is not a buildable diagram as far as I can see. It is missing information. I see the (2) three way valves but no control sequence for example.

The biggest problem I see which would be typical for anyone is, you may have to build two or three installs before you are mastering how it works. This is where you have to have the factory support for your install and do it the way the factory specifies. You have to be in contact with the dealer/factory, be asking them these questions which are certainly valid, because they will ultimately be depended on for resolving any difficulty you may have.

For example, they are probably offering the buffer tank as a factory supported reference design for your baseboard application, but may also offer a mixed reset primary secondary scenario. You would have to discover if Windhager supports homeowners self installs or requires qualified, licensed or certified. installers only. You would have to be in the position where you are understanding what the factory is telling you and providing you for their requirements. I looked online for their installation manual but did not see it.

Certainly the time to discover this is now at design time and not later after the boiler has been installed, and as you can see from the threads here, possibly with changes that coulda woulda shoulda been made on the first time around.

I never expect other electricians to know what I know and certainly never expect that from the customer. My opinion is it is a job for a heating and controls professional, because this saves money over the life of the install and because of the expertise and experience required, but you are certainly welcome to do your own work. Doing your own, you would need expert and responsible guidance, which only comes from either the factory or your licensed contractor.

There is a lot to learn here but also a lot of posting of what has been done that owners are advising not be done.

If I were doing the install, I would be in the same position of gathering all of the factory requirements, installation diagrams, and proceeding from there.

 

[__dan]

It would be a very interesting design if the Energy Tank could be a relatively standard indirect DHW tank. You would need an anti scald mixing valve at the DHW output of the tank because of the direct tie to the boiler and I see how it may work. I would want to submit a few changes for approval and it looks promising.

 

[velvetfoot]

Thanks.