HELP! Central heating problem....

Mics_chick

I really hope someone can help with this problem

Late last night we noticed that the radiators weren't getting hot.
Usually this means our pilot light has blown out but it wasn't that this time.

OH is quite handy so he thought it might be the pump. He's checked it out but that's working too coz the water is warm in the pipes on both sides of it so he can't work else what else it might be....???

Any help very gratefully received

closed

bleed them, check thermostat settings (wall and trv's if you have them), check 3 way valve if you have one.

What type of system, boiler?

spakkker

Try posting in the "in my home" forum on this site .
Maybe turn all radiators off except one and see if that works. Can you hear/feel the pump working?
Is thermostat turned up?

Mics_chick

The system is pretty old and it hasn't got a wall thermostat at all.
It was in when we moved here 9 years ago and we've not been able to afford to update it but then it does work well so the only reason to change it would be for a more efficient system.

Could the problem be sludge clogging up the system?

victor2

As spakkker says, can you hear or feel the pump working? The water both sides could quite easily be hot even if it's not working. It sounds like the boiler itself is working, so that's the next obvious port of call.

Wherryman

Mics_chick wrote: »

he thought it might be the pump. He's checked it out but that's working

Is the pump actually working?
Can you feel it start or hear it pump?
The hot water water may be on both sides of the pump due to gravity feed in the system.

ChiefGrasscutter

I'll go for the pump is knackered.

The system may well thermosiphon (ie hot water rises, so it sort of circulates by itself -badly) with the diverter valves open but nothing to pump the water through -which is why the pipes are warm on both sides of the pump - even if its knackered. The first radiator in the system after the boiler may be getting slightly warm - but the rest will be cold.

Depending on what sort of pump you have... some you can take out a central pump bleed screw from the centre of the pump casing and you can see if the spindle is turning behind this bleed screw: may help the diagnostics.
Just because the pump is humming - made not mean it is actualy turning/working.

The boiler may rapidly cycle with a malfunctioning pump - ie the burners switch on and then off as the boiler is heating up water which has nowhere to go as its not being pumped - so it switches off again, waits until the non flowing water in the boiler cools then switches on again..... and so forth.

As ever I'll be interested to see what IS the cause.

Cost of a new standard no frills pump vary from around £50 to around £120 (thats the cost of the actual pump) depending on the size of the system and whether the pump is a cheapo or more expensive type.

Sludge in the radiators usually manifests itself as a cold patch in the middle section (lengthways) of the radiator and from the middle (heightwise) to the bottom. Air in the radiators can easily be detected by the top of the radiator being much cooler than lower down the radiator across the whole width, how cooler depends on how much air is in the radiator.

Hope this helps