boiling hot water, but no heating. Any ideas?

[juliojulio]

Hello. I'd be very grateful for some advice in case I can fix this myself. Thanks in advance!
Ihave very hot water but no heating at all.

I have two timer switch boxes (very old school looking with a thing that you can pull accross/ moves across). These are under the main timer box with the dial on.
Obviously one is for heating, and one is for water. There is hot water TO both boxes. But only hot water coming out the bottom of the left one. So I assumed that the left one is the water pipe as the water works fine.
Working on this assumption, I manually moved the switch across on the right hand box, and lo and behold, hot water began to flow through it. This is when I thought I had fixed it and that is was something to do with the timer. I also turned the knob on the kitchen radiator, and it gurgled and i felt a little warmth in the pipe running up to it.
BUT, the radiator didn't heat up and the heat faded away. But it remained hot in the pipes under the two boxes.
The last people who lived in my flat replaced the pump very recently and the boiler is obviously fine. How could i check the pump is working? Or does anyone have any other ideas of what it could be?

 

[tryitandsee]

The 'little box' I assume is the motorised valve. Common problems with the motorised valves are well documented in the front page of this forum.

The small motor (within 'little box') that moves the spindle is probably broken/burnt out. The motor is very easy to replace insitu, costing £20-30.

 

[juliojulio]

Thanks for your response.
I did manually move the switch accross and hot water flowed down the heating pipe, so even if the motor is broken, surely the radiator should heat up afterwards? But seemingly the heat never reached the radiators.
This seems strange. Any idea why this could be?

 

[no66]

Are you making sure that the manual lever is latching ?????????

 

[tryitandsee]

Did you read through the FAQ's under the title;
Hot water OK but no radiators hot (or vice versa*): Motorised Valve Failure

 

[tryitandsee]

I might be wrong on this, but I think the valve is on a spring that closes the valve, the motor opens the valve against the spring, so when you did it manually for a few seconds it let hot water through, when you let go, it shut under the power of the spring.

 

[juliojulio]

Yes, I have read the post about the motorised valve, so i will try that in the morning.

The manual lever did latch and hot water remained in the pipe for a very long time - until I switched it back an hour later. So I think the valve does remain open with hot water flowing through it. It just never gets to the radiators, it seems.

 

[bengasman]

Open vent system could well be soiled. Open valve with lever and hook it behind catch. Leave it there all day and see what happens, when other valve is closed