Very Hot Rads !

Norman-B

Problem with central heating.
My 80 year old dad has gas CH and over the past few days the Rads have started to get very hot. So hot he has to turn off the heating. He has no thermostats on the rads. He has a room stat but no control on his hot water boiler, apart from a thermostat at the top of the boiler. Could there be a fault with the boiler stat, which was replaced 2 years ago.

Any advice welcome. Plumber due to visit next week.

Gaz_Hammer

Hi,
first thoughts are that the room stat is faulty and not not shutting down the heating when the temperature is reached.
Does the room stat make a clicking noise at some point while turning it up or down? If not then that will be the problem or it could be the calibration of the stat has gone kapput.

Gaz

Norman-B

Gaz, thanks for the prompt reply.
The room stat is set on 20 degs and does make a clicking noise when moved. I don't know anything about the subject but my gut feeling is that it's the boiler stat.

Gaz_Hammer

Sounds weird if it is the boiler stat because its the room stat which controls the radiator temperature.
If not the room stat then unless its a really old type system it will probably be a fault with a motorised valve sticking open or not closing for some reason which works in conjunction with the room stat.

Gaz

Gaz_Hammer

Hi Norman,
forgot to ask! What boiler is it?

GAz

Norman-B

Ah, good point! Yes, the system is over 25 years old. It is serviced every 12 months but you might have hit the nail on the head re the valve. I guess we will have to wait for the plumbers visit.
Thanks again.

Gaz_Hammer

No Problem,
Hope you get it sorted!

Gaz

plumb1_2

Sounds weird if it is the boiler stat because its the room stat which controls the radiator temperature.  
If not the room stat then unless its a really old type system it will probably be a fault with a motorised valve sticking open or not closing for some reason which works in conjunction with the room stat.

Gaz

If its an old system and not been altered,it will not have a motorized valve.
The room stat will only control the pump,

Gaz_Hammer

If not the room stat then unless its a really old type system it will probably be a fault with a motorised valve

Yes I know, the sentance probably read wrong.

boiler_man

Hi

With these types of older systems the temperature of the hot water and radiators is controlled by the boiler stat.

Have you tried turning it down to minimum? when its at minimum does the burner switch off or does it keep on running until it starts boiling. This would indicate the boiler stat is faulty and would normally be accompanied by lots of noise from the boiler.

plumb1_2

Hi

With these types of older systems the temperature of the hot water and radiators is controlled by the boiler stat.

Have you tried turning it down to minimum? when its at minimum does the burner switch off or does it keep on running until it starts boiling. This would indicate the boiler stat is faulty and would normally be accompanied by lots of noise from the boiler.

He has quoted that the system has a room stat,so the temp of the rads should be controled by the room stat which will turn off the pump.
The boiler stat will control the temp of the hot water,and if it is a fautly boiler stat,the temp of the hot water would be scolding and makeing lots of noise.
All in all it sounds like he has a faulty room stat,it could be sending a perminent live to the pump,even though you here a clicking noise when its turned down.
But we are guessing on what type of system it is.

Has the plumber been yet?and what was the outcome?