Grant Vortex 21e - no DHW or CH

[Woody12]

We've got a Grant Vortex Pro External Combi 21e. It's been working brilliantly; it's recently had a service and a new DHW pump and expansion vessel fitted, around 4-6 weeks ago.

However, Friday evening we lost both CH and HW (cold water comes through the hot tap). The boiler fires up fine and gets to temperature, however, neither the DHW pump or CH pump kick in and eventually overheats. Both pumps are hot to touch. The heat exchange is cold however. The system holds pressure.

I've bled it through the manual vent and there doesn't seem to be any air in the system.

Anyone know what the likely cause might be?

Attached photo shows new pump.

Thank you!

 

[Hairymelon]

I presume the 21e has the pcb with 8 neon lights to indicate which pump should be on.

 

[Hairymelon]

Thinking about it the dhw pump and dhw heat store have priority over the c/heating. So if programmer calling for Dhw and c/h,c/h won’t come on until dhw store is satisfied. Try operating boiler with hw off and ch only on. As diagnostic aid. Possibly new pump faulty or air trapped in pipe to dhw pump
However your controls may be ch only time switch / hw on continuous without timer

 

[Woody12]

Thanks HM.

Yes, it does have the 8 leds. The led light is on for DHW, but the pump doesn't run. The flow light also comes on when the hot tap is in use:

Unfortunately it won't let me turn the CH on before it overheats.

Would the pump still run if there was an airlock in the pipe to the pump?

What's the best way to test the pump?

 

[BoilerBob]

Dhw pump maybe u/s. Bob

 

[Woody12]

Just tested the newly installed pump and it is indeed not working. Taking it back to the merchants tomorrow. Will report back once the replacement has been installed.

Thanks for the help and advice chaps.

 

[BoilerBob]

Bloody pumps always going tax’s up. Bob

 

[Woody12]

New pump installed and now back up and running! Thanks chaps!