Mopar Muscle Association UK

Hi all, any one with any knowledge of wood stove central heating ?
I installed a woodburner stove with back boiler 2 years ago. Worked well, runs 5 rads, a big hot water tank , and a heat loss towel rail.
The hot water tank runs on 28mm gravity,with a thermostat on the return pipe to the boiler, which in turn turns on the pump for the rad circuit.
I noticed that the stove boiler had been tarring up, indicating it was running too cool.
I have now fitted a LK thermoVar loading valve into the system at the hot tank return to the boiler, to address the cool running problem, this send the water just around a loop at the back of the boiler, until the load valve senses that the temp at 55 deg, at which point it opens up the hot tank return water to mix in with the boiler.

My problem is I now get a terrible water rush and banging when the thermostat opens up, just like there is a lot of air in the system. I've bled and bled it , but it still does it.

Theeww....

Help, any advise !!!!!!!!!!!!!!!

Cheers Johnny

In my experience, tarring up in the firebox is caused by burning wood which is not properly seasoned. Increasing the temperature will help but may move the tar from the firebox to the chimney.


Shayne

I think he means the water system has problems, you can get proper stuff to put in the system, stops the water rotting I soppose, like anti freeze,adrian may be able to advise

I think he means the water system has problems, you can get proper stuff to put in the system, stops the water rotting I soppose, like anti freeze,adrian may be able to advise

Can you draw a sketch of how you have piped it up.

charger01 wrote:Can you draw a sketch of how you have piped it up.

Thanks,
Here is the diagram of the design that I used. This has worked well the last two winters.



After I noticed that the boiler was not getting hot enough , I fitted a LK 820 ThermoVar load valve , and a loop, what when it has atarted wooshing and banging , when the thermovar opens.













This is how the boiler is piped up until last week(no problems)



This is how its piped at this time , with load valve and loop

i know sweet FA about plumbing and rent a heated bed sit


the valve closes the water inside the pipe, inside the fire boils.

water turns to oxygen leaving a gap , space

this space is surrounded by a copper pipe now at 90 , 150, 400c !

the valve then opens and 55c water hits the pipe

like trowing water in a hot pan.

P.m d you.

i run a very similar system but with no loop and i run a Charnwood control system with two pipe stats on the gravity flow and return, a room stat on the landing, and a heat leak t'd off with a couple of 90* bends before the HW Tank (i have a tank stat that shuts off the flow to the tank via a valve so no tank pressurizing, the flow is the pushed around the 90* bends to the heat leak)

But tarring in a boiler stove is what they do. at some point the water will cool by so much and there will still be heat in the box.

Room heater log/multi fuel burners are different and with correct fuel will run clean.


Watch when you first light the fire and get it going good, you wil get upper and side condensation and so tarring.

And always use very dry fuel, even slightly wet wood will cause spitting, and black build up on the stove insides.

There is a bit of an art to them. I had one in my old house and two in the one we are in now. Both multifuel's but used almost only with hard wood. Never used a back boiler though... That sounds like hard work if you want hot water