possible pump problem.?

[da1234ve]

Hi My name is Dave
I have a glow worm 12 hxi condensing boiler. Heating would only come on if hot water and central heating were on together or if I put diverter valve to manual. So I replaced the mid position valve and since refilling the system when I turn on heating or hot water temp goes up rapidly then cuts out. I have bleed all rads and pump, the pump feels like its working put small driver in and it turns freely. Don’t mind replacing pump just would like to know what would be a suitable replacement pump for a (Grundfos multihead G P/N 59506180_ PC:0840_IP 44_TF 110_Class F).

 

[Agile]

Is the pump shaft spinning?

If not is there voltage applied to it?

Tony

 

[da1234ve]

yes the pump shaft is spinning.

 

[Agile]

Well in that case the pump is working and not needing replacement.

May be air in the system.

Turn off all TRVs except one and run heating.

Open second TRV and close first.

Repeat that until you have last TRV the only one open.

The open all TRVs and if you were lucky it may all work!

Tony

 

[da1234ve]

thanks for your help. I'll give that a go, maybe i didn't get all the air out of system when i refilled it. would air in the system be a possible reason for temp going up rapidly then heating or hot water cutting out then coming back on intermittently.