Wood / gas boiler coupling

Heating, insulation, ventilation, VMC, cooling ... short thermal comfort. Insulation, wood energy, heat pumps but also electricity, gas or oil, VMC ... Help in choosing and implementation, problem solving, optimization, tips and tricks ...
boomcox
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Wood / gas boiler coupling




by boomcox » 03/01/22, 22:07

Hello,

I currently have a town gas boiler which provides heating and domestic hot water. It is from 1995, to see to possibly replace it.
My plan is to add a wood-fired boiler with a buffer tank (mini 1500lts) which will do the heating alone.

the question I am asking myself is for the coupling. If I pass the hot water from the buffer tank into the gas boiler, it must work well, right?
If the gas boiler is set at 40 °, for example, it will start up when the water is "cold". One advantage is that the gas boiler manages the temperature regulation.

I searched the net quite a bit, but found nothing ... it must not be the perfect solution.
What do you think?

Thank you for your help.

cordially

PS: if you know a wood boiler for sale in OCCAZ, let us know. I'm from Aveyron, but I can travel
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phil59
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Re: wood / gas boiler coupling




by phil59 » 03/01/22, 23:10

I have a boiling wood stove, a 500l buffer tank, a gas boiler.

I put a tp box on the buffer tank, and when the tp drops, the boiler starts working.

According to the exterior tp, for example, I put for example that the boiler starts when the tank is under 38 °, and stops it when it is at 40 °.

It's an example.

The box is a TH 10, at the time (around 10-12 €, now you have to count around 15 €, enough for an old boiler, which works in all or nothing!

Also provide valves ... and boxes ....
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boomcox
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Re: Wood / gas boiler coupling




by boomcox » 04/01/22, 18:41

Hello,

Actually that interests me as a principle!

But uh, what is a TP box?
The hot water from the buffer tank goes directly into the circuit or into the gas boiler.

Thanks for your help.
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phil59
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Re: Wood / gas boiler coupling




by phil59 » 05/01/22, 22:50

tp = temperature.

Sonoff TH10 box.

The tp probe placed in a "finger" of the tank, and instead of the boiler thermostat, the sonoff box takes the place.

Everything can be programmed either on a phone, with the software provided, or in an application, like jeedom ...

The whole thing is to have wifi at home, at the mini, with jeedom, for example, or internet for the app supplied with, Ewelink ...

In addition, when the boiler is running, it is better that it does not pass through the gas boiler, there is no need to heat, to transform the boiler into a radiator, or vice versa ...

We can put valves to do that, also not ordered 2-way boxes ... one way opens the valve, the other closes it ...

ON can create scenarios, with Ewelink, to say, for example, if tp <38 °, put the boiler in operation, and open the boiler valve.
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Christophe
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Re: Wood / gas boiler coupling




by Christophe » 06/01/22, 02:17

Did you do a research? Many subjects deal with this problem ...

search.php
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boomcox
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Re: Wood / gas boiler coupling




by boomcox » 08/01/22, 07:46

Phil59, that's what you offer but too digital for me. I want to do something more basic

Christophe, uh no !! I only did Google searches. This is also how I got to know this very nice site.

There are plenty of subjects that deal more with wood / fuel. The difference with a gas boiler is that the latter manages everything on its own. The circulator and the 3-way valve being in the boiler.

It doesn't bother me that the gas boiler becomes a radiator because it will be in a room where there is even a radiator.

I "log" the diagrams and will come back to if necessary ... it is very likely.

Have a good day, have a good weekend

cordially
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Philippe Schutt
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Re: Wood / gas boiler coupling




by Philippe Schutt » 08/01/22, 10:16

Yes it works, and yes, your boiler will be a radiator.
But (there is always a but : Mrgreen: )
in general there is a permanent draft in the old gas boilers, so by this natural draft you will heat the birds.
The overall efficiency will therefore be degraded compared to a parallel connection.
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boomcox
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Re: Wood / gas boiler coupling




by boomcox » 08/01/22, 10:28

Okay for these details, so I have to try to do a parallel assembly. Not easy because with an oil boiler there are "outputs" to connect, for example, a circulator and suddenly a pilot for a 3-way valve. With the gas… to my knowledge, there is nothing so how to find a piloting for the valve? a probe in the buffer tank for example?

I have to think about all this .... it will heat up in my head !!

Have a good day, have a good weekend
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phil59
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Re: Wood / gas boiler coupling




by phil59 » 08/01/22, 11:28

The probe in the buffer tank, is what I propose to you.

It will control the "thermostat" of the gas boiler to put it into operation if necessary.

It's super simple, using only the app provided with ...

But there, indeed, you are going to heat the birds, it is a significant loss, but not immense either.

You may not even have a 3-way valve in your old boiler ...

Mine didn't. She gave up after 18-19 years of loyal service, and I replaced her with a chilly old 23 gazliner.
THE 3-way valve is only manual, and not sufficient.

Solenoid valves are good, because the wood boiler also turns into a radiator ...

But everything works without it, just that you lose about 5-10 ° of energy in the exhaust ducts ....
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hmmmmm, hmmmmmmmmmmmmm, hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhmmmmmmmmm, huh, hmmmmmmmmmmmmm.

: Oops: : Cry: :( : Shock:

 


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