Question wood boiler assembly with accumulation

[Philippe Schutt]

Hello !

Thermostatic valve: we can do without the recirculation loop when we make a high fire, which is the case when we have a buffer tank. So I would save this circulator and this valve.

No! No! The purpose of this recirculation is to prevent rapid corrosion of the wood boiler heating body caused by a return that is too cold. The difference between the return and offset temperature must be as small as possible.

A+

How fast is it when my boiler is over 50 years old?
In thermosiphon, a difference of 20 ° between flow and return is completely normal on ignition.
What to avoid is the condensation of fumes in the heating body. there are several ways to do this. keeping it at high temperature is just one of many.

[Philippe Schutt]

What mixture are you talking about? The 4-way mixture or the balloon outlet mixture?

simply that when you draw water from the tank, nothing prevents cold water from the wood boiler (off) coming with it. Then the circulator stops and we return to fuel oil while there is hot water in the tank.

Which brings up the following question:
Did you take stock of the circuit, like xx liters of fuel saved, with xx cubic meters of wood? at least an approximation to within 15-20%.

[ulyssesourd]

wow there ... the water at the bottom of the flask can be at 20 or 30 ° C while the water from the wood boiler is close to 90 ° C ... it will make a nice thermal shock if we do not put no recycling pump. And the same goes for the oil boiler which goes down to standby mode at 40 ° C while the top of the tank can be at 90 ° C ... This is nothing to do with your old wooden boiler which works in thermosyphon more than the the water is hot the more it draws the water so the difference cannot be very large: 20 ° C is quite good. the pump after the 3-way valve is essential because if the pumps of the wood boiler are stopped (boiler off), a pump is needed to bring the accumulated hot water to the oil boiler ...
And my pumps are self-regulating by an aquastat: the recycling pump on the return of the boiler, the wood boiler discharge pump triggers when the water exceeds 80 ° C, and finally the 3-way valve is manual which I put on 50 / 50 and the pump is controlled via an aquastat: if the water in the tank is hot enough: the pump brings the water to the oil boiler, and if not enough hot water the burner will go to complete what is quite rare.
Before I consumed between 2000 and 2500L of fuel oil annually, today around 300L = between 17 and 20 cubic meters of wood.

[Philippe Schutt]

wow there ... the water at the bottom of the flask can be at 20 or 30 ° C while the water from the wood boiler is close to 90 ° C ... it will make a nice thermal shock.

Don't panic, it's cast iron or steel, it keeps him comfortable.

if the water in the tank is hot enough: the pump brings the water to the oil boiler.

yes, here it is: what makes it just balloon water?
For the rest it's fine, I am.

[turbozender]

the more I follow your discussion

the more I tell myself that my installation will resemble that of ulyssesourd

except that I am going to modify it a bit so that the wood boiler can be completely extinguished (cut off of the burner by a room thermostat (19 °)
(so if the wood and cold tank) and a 2nd TA which will order the sending of the water tank + wood in the fuel)
and I will add a valve 3 see to decrease the inlet ° in the oil boiler

continue it interests me bcp
please

[Philippe Schutt]

yes, it seems simpler. I also started plugging in the pellet stoves like that. But the yield is less good because the oil boiler is unnecessarily heated. Now I favor the parallel mounting.

[ulyssesourd]

yes, it seems simpler. I also started plugging in the pellet stoves like that. But the yield is less good because the oil boiler is unnecessarily heated. Now I favor the parallel mounting.

Not quite: the oil boiler should never be cold, otherwise hello condensation ... you have to feed the oil boiler constantly if necessary, so it is better to have a "small" loss of efficiency than to see problems in a few years. ..It suffices to improve the insulation of the fuel oil boiler (replacement of the "flexible" glass wool by good rock wool and insulate the pipes well)

Let me explain myself better: in the event of heating (winter) the hot water which is pumped from the wood boiler and / or balloon does not "remain" in the oil boiler: the water goes directly to the radiators by making a small detour by the oil boiler.
And if ever, the water is no longer hot enough in the tank (wood boiler off) the circulator which brings the water from the tank to the oil boiler is thus cut, and the water which descends from the radiators goes directly into the oil boiler (look at my diagram).
In summer it is the oil burner that works alone (for DHW) and the wood boiler / boiler system is closed by 2 manual valves.
And in addition, in summer, nothing prevents me from turning on the wood boiler to accumulate hot water in the tank, it would be great in the event of a breakdown of the oil burner ... I have thought of everything. If you look at it on site, my installation will seem quite complex to you, but if I explain how it works and its logic, everything becomes very simple.
A+

[turbozender]

a question that goes through my head (finally 2)

are 1 "steel pipes sufficient for a 39kw boiler and 1400l buffer?


is a 100l expansion vessel sufficient
knowing that my current installation runs with an 18l which is sufficient
and that I have between 1400 and 1500 of buffer?

[ulyssesourd]

Hi Turbozender
pipes of the same diameter as those of the inlet and outlet + balloon cad 1 "1/4 must be fitted.
and for the volume of the expansion tank 8% of the total volume of the installation is required.
If you have a 1400L tank + boiler + the rest of your installation, therefore approximately (at random) 1600L so you need one of 128 L
A+

[turbozender]

hi ulyssesourd

ok so the balloon 150 l

the boiler comes out in 2 "!

1 1/4 for the boiler and for the house it will remain in 1 "(it is currently 28 copper dui and this part I do not touch)

when you have to mount the same diameter as the inlet outlet (what's the boiler?)

the balloons there will be what I will ask it is a friend who will make them to me in September (2x 700 or 750 l) it is so that it passes the door which makes 76 cm the balloons of the trade do not pass




waking up I had an idea (rare but it happens :-p)

finally I think I can do a parallel assembly

I have 2 anti-thermo siphon 1 "valve, can I use them as a non-return valve or do I fit all standard valves?