Hot waters on but no heat to radiators.

[Paradoxia]

Hi

I am having a problem with my central heating system that is really flummoxing me. The hot water system is running fine, but I am getting nothing out of my radiators...

The timer is putting the CH light on, but the pump isn't starting and nor is the boiler (but the pump and the boiler work fine when the hot water light is on).

The only things that I have discovered that is odd in my lengthy investigation is that if I put the 3 way valve to MAN / OPEN then the pump kicks in but the boiler still does not. AND the radiators will get hot with that set to MAN when the hot water is on.

Any ideas anyone as I can't figure it out and certainly can't afford a plumber at the moment ?

The system consists of:
Honeywell 3 way valve
Grunfos pump
Newlec timer/controller
Glowworm boiler

Any help would be great!!

 

[ChrisR]

You need a new motor in the head of your motorised valve. Possibly a whole new valve head but that's pretty unusual.
New motor is a job for a small screwdriver and a pair of smallish wire cutters.
You can get a motor from Wickes for about £15. Or from me if you post me a tenner!
anotherletterbox at aol.com use the @ symbol.

Meanwhile if you turn your boiler stat downish, cylinder stat right up, and latch the valve in the MAN position, you'll get warm rads while the boiler tries to get the HW up to temperature.

 

[Paradoxia]

Chris - that worked a treat!

Replace the valve head, re-wired, turned heating on and it all burst into life! (I did have to get a new valve head as they didn't have ony motors in stock!! )

Typical - get the central heating working again on the hottest day of the year so far!

Thanks again for your advice!

Mark

 

[ChrisR]

You're welcome but I could have saved you some money, even if it were for a new head!.
Perhaps you'd like to send me the old head?!

 

[arkjade]

I have a similar problem.

I have just moved into a new flat and although there is no problem with the hot water, I cannot get the heating to come on. The central heating system was fitted 2 years and was checked by the installer a year ago.

It is a Vaillant boiler and we have a Honeywell Smartfit controller. The controller seems fine generally and is set so that the heating will not come on if the room temperature is less than the desired temperatyre, but when I tried to get it to come on at a higher temperature than the room temperature, it still would not come on.

I wondered if perhaps the controller is set so that it won't come on above a particular tempertaure (eg 20C). Or is there another problem?