ch not working - pump?

[DaveHope]

Central heating has packed up on Boxing day... getting a bit chilly now

No CH or Hot water. Boiler is working. Fires up fine.

I believe it may be the pump, as totally silent.
I'm wondering whether its electrical, i.e. the timer. Its an old Danfoss 103 clock affair. The timer has been a bit dodge for a while, tapping it can cause the connection to turn off.
Does this timer have seperate wire connection for boiler, pump, etc?
Does this sound like a correct diagnosis?

All help appreciated,
Dave

 

[ALCPlumbing]

Depends on the set up and which boiler you have. Either the pump will come off the same switched live that fires the boiler or it will come from the pcb of the boiler. Either way if the timer is on and the boiler has fired up then the pump should be running.
You've said the boiler fires up but haven't explained what happens afterwards. How long does it stay lit?
Does any heat circulate to the radiators?
What boiler is it?
Is it gravity fed or pressurised?

 

[DaveHope]

Cheers ACL

It's a baxi bermuda back boiler, with a thermostat on the boiler. Open vented system, and a manual 3 way valve (bit like the Rega Diverta, but even older).

Boiler comes on for 5 minutes, then switches off. If I turn the thermostat up it comes back on. I presume its over-heating because the hot water isn't being pumped?

No heat in rads or hot water tank at all. The pipe feed to the pump (about 12 feet from the boiler, in the airing cupboard with the hot water tank) is stone cold.

 

[gas112]

yep certainly sounds like your pump has gone if you are not getting either and boiler is firing.
Your system would have the pump and boiler live coming off same connection in clock or one live coming out then splitting to 2 at a junction box external to clock .
You may even have a separate isolating switch for the pump check for one that may have been switched off

 

[mcmoby69]

put your ear to the pump, see if you can hear it humming. if it is it may be just stuck and need a bump start with a screw driver.

might work for a while till you can get someone out to it.

 

[DaveHope]

Just letting you know what happened with this.

It was the pump.

Restarted it, by giving it a'love tap' whilst the system was on constant setting. I.e. a firm, but not too hard, tap on the front of the pump with the back of a wrench.

So pump is running now. Looking at replacement options as obviously on last legs (30 years old)!

Thanks everyone for your time & advice.