Central heating pump faulty?

Morning guys

I've turned my central heating on this morning for the first time in months however it doesnt seem to be working. The boiler (saunier duval f30 classic) fires up for about 15 seconds, then shuts off, this repeats itself every minute or so.

I noticed the temperature on the clock was showing as 65c, the pipe inside the boiler which runs to the internal pump is very hot, the pump is also VERY hot, however the pipe exiting the pump is cold, so the water doesnt appeaer to be leaving the pump. Am i correct in assuming this is a fault with the pump? The central heating was working fine when i switched it off in may.

How do i go about fixing this?

thanks in advance

Maybe the pump has seized during the summer's inactivity. Remove the large central cover screw at the end of the impeller spindle and see if you can turn the impeller manually, this could free it up.

ok.. wee dunt with a hammer...

I'm preparing to be told off lol but i have seen this done and work..

but i would recomend the other post about taking the cover screw off and turning manually..

Hi

I removed the screw from the pump however the pump is spinning freely, so the pump is not faulty.

The central heating flow pipe gets very hot going into the diverter valve/mechanism, however as the pipe exits the valve its cold. So seems to be this area thats the problem.

When the central heating is on, the boiler fires up for about 10 seconds, then goes off. It does this every 2 minutes or so.

The odd thing is last night the central heating did come on and was working fine! All the rads got very hot for the entire 2 hours it was on for.

However this morning its back to the same problem of boiler firing up for a few seconds and then goes off. Something seems to be working intermittently. It surely cannot be the PCB. Any ideas?!

Diverter valve stuck on HW, for whatever reason.
Haven't checked, is this a diaphragm jobbie or a motorised one..

ChrisR said:

Diverter valve stuck on HW, for whatever reason.
Haven't checked, is this a diaphragm jobbie or a motorised one..

Click to expand...

Its a motorised valve! well the motor head has a pin which pushes on the diverter valve mechanism.