Central heating Thermostats

weewards

Hi we have just turned on the heating after several months in an old house & the radiators stay cold.
The pump is running but the boiler only kicks in if I turn on the hot water control and not when the central heating is turned on only.
I read somewhere about checking the thermostat as this is sometimes set to minimum but this house doesn't seem to have one & it doesn't have thermostatic valves on the rads either, is this possible?

It's a calor gas boiler with a back burner in case this is relevant.

Any help would be much appreciated.

Yes, I have bled all the radiators.

G_M

well it's not the rads, cos the boiler doesn't fire up.

There must be a control somewhere for the heating that you've missed. Is this a new house (to you I mean)? Have you never used the CH before?

Might it have a wireless stat that is hidden somewhere?

Norman_Castle

A friend had a back boiler with a fire in front. From memory the CH temperature control was behind a panel at the bottom of the fire.

weewards

G_M wrote: »

well it's not the rads, cos the boiler doesn't fire up.

There must be a control somewhere for the heating that you've missed. Is this a new house (to you I mean)? Have you never used the CH before?

Might it have a wireless stat that is hidden somewhere?

Hi, it is a new house to us, built in 1950 ish and I know the heating hasn't been used for a year but was previously used without issues.
I am fairly sure it won't have a wireless thermostat as the previous owner didn't seem to have done anything to the house in 20 odd years and I doubt wireless controls were around before then.

My gut feeling is that there must be a thermostat or a motorised valve thing (sounds like I know what I am talking about but just something I read)

There was another message from someone that said there may be a flap under the back boiler so I will look there & report back!

weewards

Norman_Castle wrote: »

A friend had a back boiler with a fire in front. From memory the CH temperature control was behind a panel at the bottom of the fire.

Thanks, I will have a prod around when I pop back to the house later today & will report back.

Threewheeler

Have you checked that the pump is actually turning, if it has been dormant for a year it is possible that the pump may be stuck/rusted.
If there is a large black cap on the back you can try turning it to loosen the stator. It may free up, if not a good old fashened hammer tap/bank on the side may free it. Try it, it worked for me.

victor2

Is it an older style system - gravity fed with a hot water tank?
Many of those cannot have heating without hot water. The controls should be set so that switching on the heating also switches on the hot water. However, is it possible you have improperly set controls? Just guessing here, but having replaced the control for my old heating system, I did know I had to have one that was suitable for a "gravity fed" system, which switches on the hot water whenever the heating is on.

weewards

Threewheeler wrote: »

Have you checked that the pump is actually turning, if it has been dormant for a year it is possible that the pump may be stuck/rusted.
If there is a large black cap on the back you can try turning it to loosen the stator. It may free up, if not a good old fashened hammer tap/bank on the side may free it. Try it, it worked for me.

Hi, yes I found the pump under the floorboards to the left of the boiler and it was humming but I removed the screw (with the power turned off) & I could turn the impeller easily. I then turned on the power and nearly lost my screwdriver as the impeller spat it out LOL

weewards

victor2 wrote: »

Is it an older style system - gravity fed with a hot water tank?
Many of those cannot have heating without hot water. The controls should be set so that switching on the heating also switches on the hot water. However, is it possible you have improperly set controls? Just guessing here, but having replaced the control for my old heating system, I did know I had to have one that was suitable for a "gravity fed" system, which switches on the hot water whenever the heating is on.

Good point, I wondered that but the control does have separate HW & CH controls. The controller was installed by a qualified plumber as I have seen the Bill! so I hope that he did it right.

I will report back after I have gone back to the house shortly.

Thanks for everyones advice so far.

G_M

So the pump is powering up when the CH is turned on, but the boiler does not fire?

You might want to try posting the problem here:

http://www.diynot.com/diy/forums/plumbing/

Lots of heating engineers and plumbers visit this site.

They can be a bit abrasive with unclear posts, so be as clear as you can with type of boiler, what exactly the problem is, what you've tried with what result.

But they'll give good advice.

(you can attach photos too)

stator

It sounds like the exact problem I had with my back boiler.
Is it a Baxi Bermuda ?

If you look at the bottom of the fireplace there is a flap that you fold down and it has instructions on it.

Basically you turn the thermostat knob(behind the flap) into the off position, leave it for a while and then turn it up to a high setting and the fire will try to ignite (it's an electronic ignition). Sometimes it doesn't work first time, you turn it off, wait a bit and turn it on again.

That's always worked for me.