CH Problem

[Alan1]

My boiler keeps overheating and shuting off. I\\\'ve replaced the thermostat, but no joy. It works with the setting very low.. though this is very little heat. I think i might have air in the system as the pump does\\\'nt bleed any water just hisses when the screw is removed (whilst the pump is on). Any suggestions??

 

[oilman]

First operation maybe to turn boiler off and check whole system for "air". It might be hydrogen caused by corrosion. Is the gas coming out of the pump only available when the boiler cuts out? If so it may be steam, especially if you have a sealed system. Then check pump is rotating. If it hasn't been run for a while it could be siezed. More info would help in diagnosing the problem, what type is the boiler?, how old is the system? Is it a sealed system or open vented? Has pump been off all summer? etc. If you have only one pump then it is probably used to heat the hot water as well, so is less likely to be stuck. Try some of these things first and let us know what the effect is.

 

[corgiman]

My boiler keeps overheating and shuting off. I\\\'ve replaced the thermostat, but no joy. It works with the setting very low.. though this is very little heat. I think i might have air in the system as the pump does\\\'nt bleed any water just hisses when the screw is removed (whilst the pump is on). Any suggestions??

sounds like lots of air chap

try turning the system off on undoing the pump screw untill water comes out

if that dont work check the f & E gtanks got water.

if it has then would think you have a blocked cold feed.