No HW or CH - any help or advice

[stevebh]

I currently have no hot water or heating in the CH system. When the HW and CH system is turned on, the boiler (Potterton Netaheat 10-16 Mk II) ignites but only runs for about 1 minute before switching off. The pump (Grundfos Super 4 Two Speed) makes a noise and gets quite hot after a period of time and so does the pipes either side of the pump - but only for about 3-4 inches (think the heat from the pump is causing this). The motorised valve (Sunvic DM5601) is working and turns freely.

The room and hot water tank thermostats are both turned up high. Any help or advice would be appreciated as to what the cause might be.

 

[ChrisR]

If the boiler's getting hot it sounds like the pump's dud. You do have an old one. Try removing centre screw, poke flat screwdriver in, turn shaft.

 

[stevebh]

I have now checked the pump and it is not stuck - does turn when boiler is on.

I have also checked the header tank - this was empty due to a stuck ball valve. I have now freed this and the tank is full again, but the boiler still does not stay on for more than about a minute.