Central Heating Radioators Cold

Hi All,

I have a gravity fed c/h system with wall mounter boiler and Hurstmann programmer which I fitted a few years ago. All has worked fine. the other night I switched on the h/water and c/heating to test the rads as it hadn't been fired up for several months. The boiler fired up and the thermostat in the living room goes on and off when you turn it.

Trouble is the rads are staying cold. Could this be a faulty water pump ? We had a new one fitted about 8 years ago. The rest of the c/h system is original.

We also live in a hard water area, Hampshire so maybe this has shortened its life if it is the culprit.

Any advice before I call in the plumber would be gratefully received.

Many thanks

Chris

If the pump hasn't been used for a while, it has probably seized. You may be able to unseize it.

There should be a cap on the end of the casing which you can unscrew and temporarily remove. (Very little water will come out). You can see the end of the shaft - and see whether it is rotating. If it isn't, turn the system off and rotate the pump shaft to and fro with a screwdriver (there should be a slot on the end of the shaft for this purpose). Once you've got it moving freely, turn the system on and try again.

If the pump is free but still doesn't rotate when the CH is on, it is probably failed or there may be a wiring fault.

Am I right in assuming that the HW circuit uses gravity circulation (i.e. needs only the boiler on) but that the CH is pumped (needing the boiler

*and* pump on)?

If not - i.e. if it is fully pumped - there may be some control valves which could have failed. Come back with further details if you need more help.