HW is heating up fine but CH not staying on.

[GCR99]

Hi

I have an oil fired Worcester boiler open system, two mid position valves, one for water and the other for heat. Last year I replaced the CH valve and have recently changed the Drayton timer, as one of the override buttons seemed sticky. I changed like for like ,so no problems with configs etc.
The water clicks on fine and is nice and hot, so the pump must be functioning or am I mistaken there? On the odd occasions the CH clicks on, the boiler runs for a couple of minutes and switches off although the stat is still asking for heat. The boiler never stays on long enough to heat the rads, so I don't know what the problem is.

any advice will be greatly received

 

[Hugh Jaleak]

I'd check the CH Valve is working, if the heating hasnt been used all summer it could have stuck shut. Open it manually and see if that lets the rads heat up. Boiler may be switching off because the water isnt circulating, boiler stat senses temperature reached so shuts boiler off.

Assuming you havent got an immersion switched on, the boiler is heating the HW ok, so unlikely to be a faulty pump.

 

[GCR99]

I'd check the CH Valve is working, if the heating hasnt been used all summer it could have stuck shut. Open it manually and see if that lets the rads heat up. Boiler may be switching off because the water isnt circulating, boiler stat senses temperature reached so shuts boiler off.

Assuming you havent got an immersion switched on, the boiler is heating the HW ok, so unlikely to be a faulty pump.

Thanks for the input, I have removed the CH valve and checked the small valve. It is moving freely. I replaced a towel rail in the summer so maybe it's an airlock somewhere? I have bled the rads and all are spitting water.