wood boiler and buffer tank: problem

[phil88]

Hi,

we have owned a farm in the 88 since 6 years, and in an environmental concern, we produce most of our products, food, furniture and other. We recycle to 80% see more. Last link: the heating that we change from gas to wood.

So, I installed an 28 kw (recycled by thermostatic valve) log wood boiler associated with a 1000 buffer tank: set connected to the existing circuit.
If all works, however, I have some problems.

The tank and heating circuit "couple" only works when I recycle to 2/3 (3-way valve out of 3. Graduated from 1 to 10.).

As soon as I recycle beyond, ie to 1 / 2 5 position of the valve, it picks up, and the water flows through the return circuit of the balloon and thus blocks the hot water supply.

manual intervention is necessary. I neutralize the ball for more hot water in the circuit



the diagram attached is in fairly real proportions.
knowing that I have 9 28 tube m from the boiler to the balloon.

thank you for your suggestions.

[loop]

Hi Phil,

I have a doubt in your description.
On my oil boiler recycling valve (it is a 4 channels but the principle is the same) the graduations go from 0 for 100% recycling, ie the radiators water turns in a loop, to 10 for 0% mix, and all the return water goes back to the boiler.
Donate in your case, you say that 5 you recycles more than 3, ie that the water radiators is colder 5 than 3?
Anyway, by turning the valve, you favor the passage in one circuit rather than the other, and there is surely one that has much greater pressure losses than the other.
The ideal would be to test the flow in the circuit, just after the heating circulator, with the valve in the extreme positions.

A+

[phil88]

Hello,

I will express things differently. Whether graduated from 0 to 10 or from 0 to 100%, we get the same result.

When I recycle to 60 / 65% with the heating circuit, so 35 / 40% of hot water intake in the radiator circuit, my installation works. The balloon is charging at the same time the radiators heat, but moderately.

If I want more hot water in the radiator circuit so a less important recycling, of the order of 40 / 50% and beyond, there is confusion in the circuit at the level of the BT. the radiator return water goes directly back through the BT return instead of going to heat up at the boiler. From which my manual intervention, I neutralize the BT.

I want to be able to recycle from 0 to 100% without disrupting BT loading.
Is there a technical solution?
place a circulator to force the fluid, for example.

[Christophe]

If you have a traffic reversal (I had one and this is often the case when you have 2 circulators, 2 circuits in parallel and 1 or 3 valves or 4 channels).

A) In your case if I understood correctly it is necessary to prevent that the 2ième circulation circulator does not reverse the flow in the BT, so it seems to me that it just missing a flapper somewhere on the balloon,

On your diagram, it is therefore necessary to prevent the water from going up in the exchanger of the BT, so put a valve either at the entrance or at the exit of the BT.

B) If you have valves but you have not drawn them, it will be more difficult to solve ... may be that playing on the 3 speeds of the circulators you can do it? That of the boiler to the max and the other to the mini.

If you have some pictures of your installation, it will be easier to help you.

ps: you can study our montage (plans + photos) here https://www.econologie.com/forums/chaudiere- ... t4589.html

[phil88]

Hello,

to put a check valve is unthinkable, because myBT is loaded from the top and redistributed in the radiator circuit from above also.

[Christophe]

So this operation is completely normal:

. the radiator return water goes directly back through the BT return instead of going to heat up at the boiler

No?

So it's a problem of pressure drops, put 1 or 2 balancing valves should solve ...

[phil88]

effectively.

I understood from the start that my length of boiler balloon tubes created significant loss of loads.
And considering my schema it is quite logical the water choose this passage.

I specify that the position of the elements boiler balloon were to me by the configuration of the places.

so I see the balancing valve, its operation, but where to place it?

[loop]

As soon as I recycle beyond

it's this phrase that made me doubt, you meant as soon as I recycle less!

Sinon

Adding a throttle with a valve at the bottom inlet of the buffer tank (between the return tee and the low tapping) will promote circulation to the boiler, but I am still surprised by your report because:
The boiler circulator must promote "direct" circulation
If the ball is hot, you should not see the difference between the circulation from the boiler or from the balloon.

Is your valve properly fitted? A confusion between the inputs and outputs is possible.

A+

[phil88]

yes everything is correctly mounted

checked by two professionals.

[Christophe]

Well you should ask them the question of your problem right? If they think everything is ok and you do not?