Vaillant Boiler Issue

[Peter GEE]

I have a Vailliant boiler that produces gallons of hot water with no problem but no hot water for central heating. The boiler is pressured and holding well. The pump gets hot but nothing after that shows any heat. Has the pump failed? When running I canot feel any vibration from the pump. Is there an easy way to test it? We are in lockdown and do not want anyone here and I have changed pumps before so is it worth trying a new pump? It is a VP5-ZE15PC PUMP.Thanks

 

[Wayners]

All rad valves are (thermostats) open and no air in them?

 

[Peter GEE]

yes all fine

 

[Deleted member 267285]

What model of Vaillant?

 

[Peter GEE]

VCW GB 242 EH VCW GB 282 EH

 

[Deleted member 267285]

I would be looking more towards the diverter arrangement, like the microswitches, servo valve, diaphragm etc. You’re getting hot water so wouldn’t have thought the pump.

 

[ianmcd]

it is not the pump, as already suggested look at the diverter valve

 

[Peter GEE]

Right now when switching on power the fan starts up continues for ever and the boiler will not light up when switched on, The pilot lamp "operator on" does not light. Now baffled.

 

[Peter GEE]

I have looked at the diverter valve and the pin is protruding out turning on hot water and the pin does not move. Boiler does not light fan runs. No green light. When I press the differential valve cam the diverter valve moves.

 

[Peter GEE]

Good news Thanks to https://www.diynot.com/diy/members/chris_w.267285/ (Chris_W) and https://www.diynot.com/diy/members/ianmcd.146904/ (Ianmcd). We have a working boiler. It was decided to fit new water valve, new diverter valve new microswitch and servo. Fired up first time Hot water galore and hot radiators.Thanks for giving such good advice.

 

[Peter GEE]

I would be looking more towards the diverter arrangement, like the microswitches, servo valve, diaphragm etc. You’re getting hot water so wouldn’t have thought the pump.

We have a working boiler. It was decided to fit new water valve, new diverter valve new microswitch and servo. Fired up first time Hot water galore and hot radiators.Thanks for giving such good advice.