# Problem Oil Burner heating Back Boiler



## maire1000 (14 Oct 2011)

Recently I refurbished a room and had a 20 year old Grant back boiler replaced with a new one, to avoid further disruption in the future. Original Back Boiler was working perfectly. I now find that when my Oil Burner is running, the Back Boiler is heating up and gurgling etc. Can anyone offer a solution. please. I fear that I might have to have new fireplace etc removed to access pipes? A small "door" located on the side of the chimney breast allows access to the circulating pump and some pipework. Here's hoping!
Thanks in advance.


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## villa 1 (14 Oct 2011)

Get the plumber who installed your new boiler a call. This new boiler has to be linked to a properly designed dual heating system. In a properly designed dual heating system the two boilers should not heat each other. If the oil boiler is heating your back boiler you will have huge heat losses up a cold chimney flue leading to large heating bills.


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## Westie123 (14 Oct 2011)

Basically, your new back boiler is functioning just like a radiator. You can get a one-way valve fitted into the outlet pipe of your back boiler. This is like a hinged flap which opens only one way. It will allow water to flow from the back boiler out when the fire is lighting, but will prevent water flowing into it when the oil burner is on.


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## maire1000 (14 Oct 2011)

Thanks, Villa 1, for your reply. Rang the plumber (who did the job today)  but no reply yet. Dual system was working fine with old Back Boiler. Problem developed since fitting of new back Boiler. Would you think the new fireplace will have to be removed to rectify the problem?


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## maire1000 (14 Oct 2011)

Thank you for that info, Westie 123. Now 2 days ago when I was aware that a pipe at the side of chimney breast was getting hot, I rang the plumber. He said that this was caused by "heat creep" and that the Back Boiler wasn't being heated by the oil burner. (Just last night that I realised that the BB was being heated too) 2 days ago, I made the suggestion of fitting a one-way valve to prevent the pipe being heated (but I'm no plumber!). Plumber said a one way valve will get "bunged up' and would be dangerous as it might explode??


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## villa 1 (15 Oct 2011)

Westie123 said:


> Basically, your new back boiler is functioning just like a radiator. You can get a one-way valve fitted into the outlet pipe of your back boiler. This is like a hinged flap which opens only one way. It will allow water to flow from the back boiler out when the fire is lighting, but will prevent water flowing into it when the oil burner is on.


You most definitely cannot fit a non return valve on the outlet from a back boiler/stove
If you fit a non-return valve(one way) on the outlet pipe from the back boiler you could have a nasty incident if there is a power cut. This is a highly dangerous practice that is undertaken by installers who do not understand the working principles of dual heating system.
The back boiler will need a unrestricted primary circuit to the hot water cylinder and a seperate heating circuit linked to the oil fired boiler which can incorporate a non-return valve.


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## maire1000 (15 Oct 2011)

Thanks for that very useful information, Westie. What I really need to do, I believe now, is to get my back boiler disconnected somehow and get it reconnected in the same way as the previous back boiler  was connected, if that is possible (without removing the new fireplace). Plumber slow to get in touch.


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## DavyJones (15 Oct 2011)

Very possible that an old existing non return valve (one way valve) has stuck in the open position from the draining down and refilling. It has happened me more then once and caused the same symptoms as you describe.

Might be worth a check. This valve will be found on the secondary circuit, usually near pump.


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## maire1000 (15 Oct 2011)

Thank you very much to all for your assistance. Much appreciated.


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## Shane007 (15 Oct 2011)

villa 1 said:


> You most definitely cannot fit a non return valve on the outlet from a back boiler/stove
> If you fit a non-return valve(one way) on the outlet pipe from the back boiler you could have a nasty incident if there is a power cut. This is a highly dangerous practice that is undertaken by installers who do not understand the working principles of dual heating system.
> The back boiler will need a unrestricted primary circuit to the hot water cylinder and a seperate heating circuit linked to the oil fired boiler which can incorporate a non-return valve.


 
+1 and this is also why dual coil cylinders should always be fitted when solid fuel and oil is connected. Too many systems installed that share the same coil.


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