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Central Heating problem?

Hello all,
I have a glow Worm spacesaver and the problem is that when I put the heating on,the boiler fires up for approx.2 mins,then cuts out as if it is up to temperature.
The radiators remain cold as does the "Hot" water.
I have bled everything in sight and checked the pump which appears to be running alright.
Any help would be greatly appreciated......Thanks.

Alan.

Alan., July 2009

home Fix label D.I.Y label_important Plumbingdone

Keith,thanks for the reply,here's the update.....again !
I decided to have another go at it today.
I bled the upstairs radiators first and ALL 4 were full of air (There seemed to be no water in them at all lol).
The downstairs weren't too bad.
I turned the heating on and the radiators began to warm up (Not to full) but they were warm,the warmest seemed to be the bathroom upstairs,but the one in my kitchen - closest to the boiler is stone cold !!

Alan.

Alan, August 2009

hi if the pipes either side of the pump are very hot but only around the pump not down towards the boiler or cylinder then it's prob the pump thats knackered, the solenoid valve on the boiler only applies to the gas valve & won't have any effect on the temp.

Keith Gillyon Plumbing, Heating & Building Services. Southampton., August 2009

Hello all,back again with sort of an update.
I have left it for a while and someone reminded me about it when they said it was the Thermocouple that was at fault.
The pilot light stays constantly on,it's only when on hot water or heating,the boiler lights up for a couple of minuits then goes out (NOT the pilot light).
On ringing up for a thermocouple,the bloke said it wasn't that what was faulty.

Alan.

Alan., August 2009

If there is a motorized valve on the system it would normaly need to open on demand which would then switch the pump on(and the boiler).pumps running so valve or valves must be working.

den, July 2009

In my opinion only,I think it may be the stat "Thinking" it is up to temp and shutting it off , possibly due to no water circulation and the sensor is heating up quickly and shutting it down ?????
I have looked for a mag valve which I assumed would let the water flow,as I said earlier,I do refrigeration ! lol
Alan.

Alan., July 2009

Is the boiler cutting out due to thermostat getting up to temp or are you saying the gas selonoid valve is shutting it off, is it a fully pumped system.

den, July 2009

The impeller is running.
It's looking more and more like a solenoid valve by the second.
Alan.

Alan., July 2009

could be the pump, some pumps(grundfoss) have a central screw you can undo to see if the impeller is turning.

den, July 2009

Saturday :- I drained the whole system and the small tank emptied,refilled the system,tried the heating and hot water and no change !
I think it may be a solenoid valve that isn't opening,but then,I am a refrigeration engineer,not a plumber ! lol
Alan.

Alan., July 2009

Tie the ballvalve up,drain some water off then untie the ballvalve to see if water is getting down the cold feed (water level might not drop if feed is blocked),sounds to me you are only heating what water is in the boiler jacket.

den, July 2009

Checked the small tank in loft and has water up to the correct level.

Alan.

Alan., July 2009

check the small tank in loft for water.

den, July 2009

Thanks for the reply.......on hot water,the pump does run,the pipes either side of it I can't touch......too hot,it is not air locked and the boiler still cuts out after 2 or 3 mins.

Alan.

Alan, July 2009

what does it do if you try hw ?
the pump appears to run ok. does it run or not ?
is the pump airlocked ?
is the pipe to the pump hot ?

hi-spec plumbing & heating (essex), July 2009