Back Boiler Query

cooket3 · 15 Oct 2012

Hi

I have just bought a house with a stove back boiler. After lighting it up and turning on the water pump, the radiators warm up to just above room temp and the hot water tank is the same or colder.

The copper pipes from the back boiler just get luke warm.

Should the water be pumped from the top of the back boiler or bottom?

Should the pump be pumping water away from the back boiler?

When I put the pump on is sounds like water is dripping in the back boiler and therefore may have an air lock, if so how do I get rid of the air lock, is there a way to bleed the boiler or air?

I have attached 2 images, hopefully these help abit. the pump pumps away from the stove and the pipe is connected to the bottom of the back boiler

//media.diynot.com/195000_194201_51374_76285139_thumb.jpg
//media.diynot.com/195000_194201_51375_76258404_thumb.jpg

Thank You

Agile · 15 Oct 2012

That pipework looks very new!

What are you burning in the stove?

What is its heat output rated at?

It looks to me as if if you expect to get 10 kW out of a stove with an output of 2-3 kW !

Heating is a specialist subject and anything needs to be carefully specified if its to work properly.

Tony

Agile · 15 Oct 2012

The installation is obviously a DIY attempt as the pump is oriented incorrectly!

You need a professional !

Tony

cooket3 · 15 Oct 2012

Hi

Thanks for the quick reply.

I was hoping it would be cheap and simple!

The pipework is just under 2 years old from what I have been told.

it probably was a DIY project as everything in the house has been, and poorly!

I dont know what make or model the stove is, or the output.

I am burting wood at the moment, and have been for hours and still doesnt get warm. I have 7 radiators, 1 large the rest small.

When you say the pump is oriented the crong way, would just turning it round the other way help fix the problem? Or should the pump be on the top pipes coming from the back boiler?

Thanks again

OwainDIYer · 15 Oct 2012

Usually, most solid fuel boilers MUST use gravity circulation (thermosyphon) for hot water, so there is somewhere for the boiler to dump heat to even in the event of a power failure.

Given that it's likely it's a bodged job I would strongly recommend getting a reputable HETAS engineer to check the system.

Boilers can explode if they're wrongly installed without proper pipe venting. There is also the risk of carbon monoxide poisoning if the flue or combustion ventilation is inadequate.

cooket3 · 15 Oct 2012

Think ill look into a prefessional!

Im curious to whats wrong

Are you able to copy my image and draw arrows etc of what the waterflow should be like? and where the pump should be

Thanks

cooket3 · 17 Oct 2012

Ive just found out the output is between 8-16KW.

When I have the stove on and the pump off the upstairs radiators get hot and the hot water tank gets warmer than before.

If I take the pump off and reverse it, so its pumping into the the back boiler, will this work? (This I believe will draw in colder recirculated water back into the stove)

Thanks

Agile · 17 Oct 2012

You have not said which way the pump is pumping!

It should pump towards the left so towards the boiler.

Probably best on lowest setting. Ideally it should not pump until the boiler is fairly hot.

The shaft of the pump should be horizontal. It can probably be rotated on the joints after loosening them.

Heat output depends on what you are burning and with common wood you only get about 30-40% of the rated valve and thats only when full and on max!

Tony

cooket3 · 17 Oct 2012

Hi

Sorry thought i mentioned

The pump is connected to the bottom stove pipes and pumping away from the stove

see pictures above for illustration

Agile · 17 Oct 2012

That seems to be wrong assuming normal the flow is at the top!

cooket3 · 17 Oct 2012

Yea I know. Ive been trying to get answers on it

Should the hot water from the back boiler be pumped OUTof the TOP of the stove?

or recirculated colder water pumped IN to the BOTTOM of the stove?

Agile · 17 Oct 2012

Teh boiler should be on the return.

Thats cooler for the pump!

For safety reasons the flow MUST go directly to the vent ( and not through the pump! )

cooket3 · 17 Oct 2012

Thanks, but feeling dumb today!

What vent?

Can you describe the exact flow directions

Thanks

warmadmax · 17 Oct 2012

get a professional in !

it sounds like your completely out of your depth,
doing something wrong like blocking the vent pipe would lead to disastrous results (unvented boilers without pressure relief can and will turn the water to steam and potentially explode!)

the vent pipe is one that's open to the air at the very top, normally above the feed tank, it MUST NOT have any way to block it off (valves etc) while the boiler is running.

cooket3 · 17 Oct 2012

hmm my stove only has 2 pipes in the back, presumably, hot water (top) out colder in (bottom). Can the vent pipe be internal going up the chimney?

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Back Boiler Query

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