Heating system gone mad

[fujifilm]

Please can someone offer some advice as my heating system has gone mad! Its a Glowworm boiler and when the heating comes on or I turn up the thermostat, it fires up and goes for a few minutes then closes down, few minutes later it fires up and then closes down and will do this until I turn the thermostat down.

The radiators get hot but I have noticed an unusual sound in the one nearest the boiler, its like a "trying to draw air in" noise, sorry I can't describe it better than that.

I looked through previous posts and tried bleeding the radiators and undid the screw on the pump, no water came out but it made a whirring noise.

The silver box which switches between hot water and central heating says sundial y plan 3 position diverter.

Hope thats enough information.

Thank you.

 

[ChrisR]

"trying to draw air in"

Could be close!

Look for points to vent air out of the system,
near the boiler
near the HW cylinder, on a horizontal pipe which goes into the side.

Then get into the loft and see if there's water in the small (header) tank
If so let some water out via a drain cock & hose on the pipes somewhere, making sure the header tank fills up again (pipe can be blocked)

 

[fujifilm]

Thank you for that, I just undid the vent in airing cupboard and water came out no air, I have a drain tap on a big pipe going into the boiler so I opened that and again hot water no air.

Let some water out of the radiator and let it run for a bit and the header tank fills OK.

But it still does the same thing, as soon as I get the sucking of air type noise the boiler stops heating, but I have noticed the pump carries on running.

I have only just moved in to the house so have no idea if anything has been changed at anytime, the programmer looks new the rest probably original 1980s. and radiators are missing from the bathroom, just two blanked off pipes are left. (They took the heated towel rails )

 

[gasgeezer]

which model is the boiler

 

[fujifilm]

The boiler is a Glow worm fuelsaver probably about mid 1980s. Most componenets apear to be honeywell

 

[gasgeezer]

sounds like air in the syst. have also known the boiler stat to lose calibration can still easily get parts for this boiler probably best to replace for more economical one

 

[fujifilm]

New one will cost me far too much, buying the house has cleaned me out. Or was that the ex wife.

Is the boiler stat easy to locate and replace, its worth a go. Thought about replacing the pump and the switch part as that seems to be reasonably cheap and I suppose it will not do any harm, eliminates them and my luck is these things pack up in winter.

 

[PEDANTICVINDICTIVEMAN]

Dont change the boiler, nowt wrong with it if it's been looked after, new boilers overly complicated and probably wont last as long as the one you have, problem could be down to a few things as this boiler relies on having a certain amount of flow throught he heat exchanger, whistly noise from radaitor could be valve/s need opening slightly, system byepass could need adjustment , cold feed could be blocked so system is pulling air in at vent/s, if the system has been put in properly and maintained properly it may only need some cleanser through the system rust inhibitor and setting up, possible new pump after, ask family/friends/work colleagues for recommendation of corgi man to come and look.