....and boiler fires for 10 seconds, temperature rockets to 70c then boil shuts off for few seconds, this repeats itsself.
At first i assumed it was the diverter valve as i got hot water but the central heating flow pipe, exiting the boiler, was cold.
But now the central heating flow pipe does get hot as it leaves the boiler, but for some reason only lukewarm water gets to the rabs upstairs. Downstairs rads are cold.
I've removed the screw from the pump and the pump is spinning fine. Hot water at the taps is also fine.
Its a saunier duval f30e classic.
any ideas what else could be the cause?
At first i assumed it was the diverter valve as i got hot water but the central heating flow pipe, exiting the boiler, was cold.
But now the central heating flow pipe does get hot as it leaves the boiler, but for some reason only lukewarm water gets to the rabs upstairs. Downstairs rads are cold.
I've removed the screw from the pump and the pump is spinning fine. Hot water at the taps is also fine.
Its a saunier duval f30e classic.
any ideas what else could be the cause?