Econoburn doesn't need a 3 way valve for boiler return temp protection!

[pybyr]

Hello all--

I had a bunch of install questions, and called Econoburn's tech line. Their tech guys were out of the office, but I actually got a call back a few minutes later from Mark Odell, VP there, and he was incredibly informative and gracious with his time, and answered a lot of my questions.

the biggest news is that he told me something that Joe Brown here on the Hearth also told me earlier today, which is that the Econoburn units don't need the 3-way mix valves for boiler return temp protection. The PLC controller that controls the boiler's other functions controls the "near boiler circulator" (that bypasses the boiler) relative to the "main circulator" to get and keep the boiler out of the condensing temps. It apparently does the same thing as the boiler reaches the end of a burn.

I'm really glad to hear that I can now skip all the thinking about which 3 way mixing valve and/or a variable speed circ I previously thought I needed for boiler return protection; my planned system just got less complex and less expensive, which is a nice turn in this otherwise complex and expensive undertaking

I wanted to share this info, as, for some, the ability to "nix the mix valve" and associated plumbing complexity/ valve cost may be a bonus in favor of the Econoburn.

Mark O also confirmed that they __definitely__ recommend the use of a barometric damper type draft control on the exhaust- the idea being that with a gasifier, you don't have the creosote worries- thought I'd throw that out there, too, as it was a subject of discussion in some other threads.

How many companies' VP calls you back and actually knows and offers this level of support? My boiler has not arrived yet, but I'm already pretty pleased with my choice of makes (not to slam any of the other makes)

Trevor

 

[BrownianHeatingTech]

the biggest news is that he told me something that Joe Brown here on the Hearth also told me earlier today, which is that the Econoburn units don't need the 3-way mix valves for boiler return temp protection. The PLC controller that controls the boiler's other functions controls the "near boiler circulator" (that bypasses the boiler) relative to the "main circulator" to get and keep the boiler out of the condensing temps. It apparently does the same thing as the boiler reaches the end of a burn.

I'm really glad to hear that I can now skip all the thinking about which 3 way mixing valve and/or a variable speed circ I previously thought I needed for boiler return protection; my planned system just got less complex and less expensive, which is a nice turn in this otherwise complex and expensive undertaking

I wanted to share this info, as, for some, the ability to "nix the mix valve" and associated plumbing complexity/ valve cost may be a bonus in favor of the Econoburn.

Using a bypass circulator for return protection is an option with any boiler (not just wood, but also oil/gas/pellet). Albeit, it requires adding an aquastat with others, since they usually don't have it built into their control.

An SPDT aquastat on the return pipe selects whether the main or bypass circulator actually gets the power. Once the return goes above a certain point (typically 140), the aquastat switches power from the bypass to the main circulator.

Personally, I like the pump method better than the 3-way valve. It is simpler to repair (pumps are readily available, and relatively standard), and it is much easier to actually know that something is wrong, since a thermostatic valve may fail gradually, whereas a pump will generally work and then just not work, so you will notice the sudden increase in warm-up time.

Since you don't have the restriction of the 3-way valve, the main pump is often smaller, and the bypass pump can definitely be on the small side (since it has practically no head pressure to work against, being mounted right at the boiler), so the electrical consumption is reduced, as well.

Joe

 

[antknee2]

Does anybody know ware I can find a diagram or pic of someones properly set up Econoburn near boiler piping , the manual leaves way to much up to your imagination no matter how many times I read it .
Thanks Anthony

 

[BrownianHeatingTech]

Does anybody know ware I can find a diagram or pic of someones properly set up Econoburn near boiler piping , the manual leaves way to much up to your imagination no matter how many times I read it .

I don't have a picture, but it's pretty simple. Put two tees on the supply, and two on the return. With two tees, you have three ports available now. From one supply to one return, you connect your gravity overheat loop. Another supply and another return get connected to your system (stick a pump with an internal flowcheck somewhere between the system and the return port, pumping towards the boiler return). With the last pair of ports, you connect a pipe from the supply to the return, with a pump located somewhere in the pipe (again, with an IFC, and pumping towards the return).

The piping and pump leading directly from the supply to the return are your bypass loop.

Joe

 

[SteveJ]

Joe,

Is this what you are describing?

Thanks,
Steve

 

[antknee2]

You guys are the best , a diagrams and explanation , thank you . makes sense to me know . Should I install the aquastat that comes with the Econoburn on the return like Steves diagram ?
Thanks Anthony

 

[BrownianHeatingTech]

Is this what you are describing?

Pretty much, yup.

You guys are the best , a diagrams and explanation , thank you . makes sense to me know . Should I install the aquastat that comes with the Econoburn on the return like Steves diagram ?

The Econoburn has a terminal for the pump, built into the control panel. No need to use an external aquastat for that function.

Joe

 

[pybyr]

Steve J- what are you using to do those drawings- I really want to draw up my proposed overall system so I can post here and get constructive critiques, but I don't know what to draw with

thanks

 

[SteveJ]

I am usiing Microsoft Visio 2003 for the drawing package and using the templates from Tekmar

http://www.tekmarcontrols.com/design.html

 

[antknee2]

Is this what you are describing?

Pretty much, yup.

You guys are the best , a diagrams and explanation , thank you . makes sense to me know . Should I install the aquastat that comes with the Econoburn on the return like Steves diagram ?

The Econoburn has a terminal for the pump, built into the control panel. No need to use an external aquastat for that function.

Joe

Thank you Joe
would it safe to say the Econoboun boiler controller and separate Honeywell aguastat only monitor the actual overall out put temperatures , one sensor under the insulation on top by 2'' supply connection and the actual water out put temp by the immersion type aquastat provided with the boiler [ not factory installed ] ??

Would it also be safe to say that that boiler protection is based on out put temperatures not return water temperatures ??
Thanks Anthony

 

[BrownianHeatingTech]

Would it also be safe to say that that boiler protection is based on out put temperatures not return water temperatures ??

Yes. They do not use a separate return temperature sensor. If the system is designed for a the right temperature drop, that will never be an issue. If there is a system design that sometimes allows a greater temperature drop between the supply and return (ie, not pumping fast enough), then it could become a problem.

If you have a system with variable-speed pumping or somesuch, which would allow the delta-T to increase, then it's important to go to a return-based protection strategy.

Joe

 

[antknee2]

Would it also be safe to say that that boiler protection is based on out put temperatures not return water temperatures ??

Yes. They do not use a separate return temperature sensor. If the system is designed for a the right temperature drop, that will never be an issue. If there is a system design that sometimes allows a greater temperature drop between the supply and return (ie, not pumping fast enough), then it could become a problem.

If you have a system with variable-speed pumping or somesuch, which would allow the delta-T to increase, then it's important to go to a return-based protection strategy.

Joe

Joe thanks
Boiler protection with a bypass circulatior is starting to make sense to me , simple to service and simple to set up just the way it should be .
Anyhony

 

[pybyr]

Their new version of their O&M;manual, not yet out in paper, but will be soon has a diagram showing the "near boiler"/ bypass (protection) circulator pointing down from the outlet to inlet, and with a check valve near the inlet, then the main circulator is down on the pipe from the load back to the inlet. That diagram also has notes that show that the near/bypass circ goes off at 150F and the boiler -->load circ goes on at 150.

It also shows the Aquastat that you (Anthony) had asked about up by the outlet, and explains in the text that the Aquastat is merely an extra safety feature to shut the air feed blower down if the whole thing gets too hot.

And yes, Econoburn's approach to this, like other parts of their design and implementation, seem simple and robust- which is very appealing to me.

 

[antknee2]

Their new version of their O&M;manual, not yet out in paper, but will be soon has a diagram showing the "near boiler"/ bypass (protection) circ pointing down from the outlet to inlet, and with a check valve near the inlet, then the main circ is down on the pipe from the load back to the inlet. That diagram also has notes that show that the near/bypass circ goes off at 150F and the boiler -->load circ goes on at 150.

It also shows the Aquastat that you (Anthony) had asked about up by the outlet, and explains in the text that the Aquastat is merely an extra safety feature to shut the air feed blower down if the whole thing gets too hot.

And yes, Econoburn's approach to this, like other parts of their design and implementation, seem simple and robust- which is very appealing to me.

Trevor thanks for the info , I will call Hank for the new manual tomorrow.
Anthony

 

[Stlshrk]

I really like that pump idea vs the 3 way valve as well. Just want to make sure that this aquastat is the type y'all are referencing.

http://www.pexsupply.com/product_dtl.asp?pID=5486&cID=294&brand;=

It is a Honeywell L6006A1244

Thanks!

 

[EricV]

I'm not sure on that one.

I think this is a SPDT like they are talking about. If so I'm going to get one.

http://www.grainger.com/Grainger/items/2E859

 

[pybyr]

the control of the circulators for boiler return protection is actually done by the PLC in the Econoburn's control panel. Below 150 (but above some minumum, so it's not running on a stone cold boiler, as I understand it), it runs the bypass near-loop circulator to keep water in & moving around in the boiler as it comes up to or regains temperature, above 150, it runs the one that delivers heat from the boiler to the load

As I understand it, I'm pretty sure that the "outboard" Aquastat as used on the Econoburn is merely a final fail-safe to cut off the intake air blower if the boiler starts getting way too hot.

 

[BrownianHeatingTech]

As I understand it, I'm pretty sure that the "outboard" Aquastat as used on the Econoburn is merely a final fail-safe to cut off the intake air blower if the boiler starts getting way too hot.

That's correct. Codes require a standard aquastat as a secondary high-limit, in case the PLC fails to stop the fan correctly.

Joe

 

[mtnmizer]

I'm getting close to having the piping done on my EBW
150 and have been following this thread..and am confused
on how to procede..

On page 7 of the current manual obtained recently via email
under plumbing connections it states :

" At times such as when there is a large call for
heat the return water temperature may become
too low. This can result in poor gasification and decrease efficiency as well as creosote
buildup in the gasification chamber, heat exchanger tubes and chimney. Low return water
temperature can also shorten the life of the boiler.
A mixing valve should be installed
at the boiler outlet in such a way that supply water can be mixed with return water
before it enters the bottom of the boiler. Check with you dealer or installer for details."

My plumber will do as I request, & I bought direct from the factory....I also
note the section regarding the startup loop.. Any way to clarify this? MM

 

[pybyr]

I'm getting close to having the piping done on my EBW
150 and have been following this thread..and am confused
on how to procede..

On page 7 of the current manual obtained recently via email
under plumbing connections it states :

" At times such as when there is a large call for
heat the return water temperature may become
too low. This can result in poor gasification and decrease efficiency as well as creosote
buildup in the gasification chamber, heat exchanger tubes and chimney. Low return water
temperature can also shorten the life of the boiler.
A mixing valve should be installed
at the boiler outlet in such a way that supply water can be mixed with return water
before it enters the bottom of the boiler. Check with you dealer or installer for details."

My plumber will do as I request, & I bought direct from the factory....I also
note the section regarding the startup loop.. Any way to clarify this? MM

After my initial conversations with Mark Odell and Dan Goede about this issue, and after getting that newest manual with the bypass pump diagram myself -- I called the factory a final time to triple-check with them again about the need for the 3-way mixing valve, given that above language-- which, when read by itself, seems to contradict the diagram that shows use of the separate pumps, controlled by the PLC, for return water temp protection- & with no 3 way valve.

During that conversation, I was told that the above-quoted language was left in the manual basically to make sure that any installer does install SOME type of cold-return protection (which can include the proper install of the bypass pump, without a 3 way valve) so that someone with a bungled installation with no return protection does not then come running back and pointing fingers at the company. I was assured that as long as you install and connect the 2-pump protection system correctly, in terms of both the plumbing and wiring of it, you can omit a 3 way valve.

Before anyone takes issue with the company "covering itself" in that way, please note that a huge swath not only of DIY-ers, but even "heating pros" aren't all that familiar with these return-temp protection issues, which, although apparently beneficial for any boiler, become crucial for solid-fuel gasifiers-- so I do not blame the company for wanting to make really-really-really sure that someone does not botch an installation and then try to blame the product/company.

 

[mtnmizer]

[/quote]
After my initial conversations with Mark Odell and Dan Goede about this issue, and after getting that newest manual with the bypass pump diagram myself -- I called the factory a final time to triple-check with them again about the need for the 3-way mixing valve, given that above language-- which, when read by itself, seems to contradict the diagram that shows use of the separate pumps, controlled by the PLC, for return water temp protection- & with no 3 way valve.

During that conversation, I was told that the above-quoted language was left in the manual basically to make sure that any installer does install SOME type of cold-return protection (which can include the proper install of the bypass pump, without a 3 way valve) so that someone with a bungled installation with no return protection does not then come running back and pointing fingers at the company. I was assured that as long as you install and connect the 2-pump protection system correctly, in terms of both the plumbing and wiring of it, you can omit a 3 way valve.

Before anyone takes issue with the company "covering itself" in that way, please note that a huge swath not only of DIY-ers, but even "heating pros" aren't all that familiar with these return-temp protection issues, which, although apparently beneficial for any boiler, become crucial for solid-fuel gasifiers-- so I do not blame the company for wanting to make really-really-really sure that someone does not botch an installation and then try to blame the product/company.[/quote]


Thanks for the update, I was hoping that was the case.

I was talking with my plumber yesterday
who's going to hookup my system.

He's done a couple of Tarms over the past
few years and they work nicely. He says to get
the pieces you want and I'll put it together....
that's what I'm trying to get my mind around.
He's never done an Econoburn.

This info helps.. MM

 

[SnowTraveler]

I have a concern regarding cycling, once the boiler is up to 150 Deg F jacket temp, the circulating pump will shut off and the primary pump comes on.
That is fine, but if you are pumping from "cold" storage, won' t this lead to repetitive cycling of the pumps until the storage is up to temp? Maybe this is ok?
I do not see a provision for both pumps to run providing a mixing effect.

 

[BrownianHeatingTech]

I have a concern regarding cycling, once the boiler is up to 150 Deg F jacket temp, the circulating pump will shut off and the primary pump comes on.
That is fine, but if you are pumping from "cold" storage, won' t this lead to repetitive cycling of the pumps until the storage is up to temp? Maybe this is ok?
I do not see a provision for both pumps to run providing a mixing effect.

That would be the situation in which you would want to install both mixing methods. There is a Termovar that is specifically for that use (blending to keep the return water up, rather than minimum-temp protection).

Joe

 

[mtnmizer]

[/quote]That would be the situation in which you would want to install both mixing methods. There is a Termovar that is specifically for that use (blending to keep the return water up, rather than minimum-temp protection).

Joe[/quote]

I can see a need to both on my system now. I would locate the mixing valve on the
intake side of the main circ pump and feed it off the output side of the boiler? Any other
details to the install?

What termovar would be best sized to a ebw 150? Tnks MM

 

[Nofossil]

That would be the situation in which you would want to install both mixing methods. There is a Termovar that is specifically for that use (blending to keep the return water up, rather than minimum-temp protection).

Joe[/quote]

I can see a need to both on my system now. I would locate the mixing valve on the
intake side of the main circ pump and feed it off the output side of the boiler? Any other
details to the install?

What termovar would be best sized to a ebw 150? Tnks MM[/quote]

There is another crude but effective technique. I use a simple 3/4" zone valve for the bypass loop. It's opened whenever the EKO circulator is on AND the inlet temp is below 140 degrees. The bypass loop goes directly from the outlet of the EKO to a point just upstream from the inlet of the EKO circulator, which then goes directly to the EKO inlet. Works fine, but it's a bang-bang controller so it cycles a bit during warmup.