central heating went made las night!

[chocdrop]

Last night the heating (on timer) came on at 5.30pm, and went off at 7.30pm. I have 2 bedrooms at the front of the house and a bedroom and bathroom at the back of the house. The airing cupboard is in the bathroom and has the cylinder there, with a grundfos selectric pump UPS 15-50, and Drayton MA 1 mid point valve(link attached but not sure it will work- http://i13.photobucket.com/albums/a259/allyourbitz/heating/Picture.jpg.

The radiators in the bathroom and back bedroom came on but the front bedrooms and downstairs rads remained cold. By 11.00pm, ALL the upstairs rads were really hot and all the ones downstairs were cold. The room stat made no difference even when turned to zero and I was wondering what might have gone wrong....I thought the motorised value might have gone on the blink i.e. the sychron motor (the pipe work either side of the pump and value were hot), the TRV's in the bedrooms were turned right down but they had no impact(and never have, so I think the sensor bodies might be knackered, but I've known that for some time now) and I bled all the rads, but no air pockets found. Any thoughts?

 

[CH4]

chocdrop's picture:

Is the pump actually circulating the water? Its impeller may be loose on the drive shaft, and the water could be circulating mainly by convection currents. Is the CH return pipe to the boiler hot?

 

[chocdrop]

me again. Checked and it does look like the motorised valve that is not working properly. I took off the actuator and flicked on the programmer for hot water and then for heating and then for both at the same time, and the slot at the back of the actuator hardly moved. I also tried to gently move the spindle on the valve with pliers, but it hardly moved (is that right?)

I can't get a plumber out to confirm what's wrong for a few days still, and to make things worse, we don't seem to be getting much hot water now? what's causing that?

 

[Agile]

If you use an adjustable spanner on the shaft of the valve it should turn reasonable easily by at least 30%.

If you put it in the middle you should get a bit of hot water and heating.

However, according to logic you should get either CH or HW regardless of the valve position so I dont think thats the only problem.

Have you checked that the feed and expansion tank is full of water to at least 100 mm? The float valve may be stuck?

If there is water in it then there is the possibility that the feed pipe is blocked.

Tony Glazier

 

[chocdrop]

Tony

Thanks for replying. I can get a little movement on the spindle and have moved it but not much joy. I'll check the tank tomorrow morning. In the meantime I think the pump might also be a problem. When the pump is on, I can hear a slight constant noise (as if its stuck) in there irrespective of whether the setting is on 1,2 or 3, whereas yesterday, if you moved the speed from 1 to 3, you suddenly heard a increased gushing noise and the water sounded like it was moving quicker.