Hot radiators, when on hot water cycle.

[Peter plumber]

Recently change a CH pump, glow worm space saver boiler(pumped CH & gravity HW), now have problems as it appears to be allowing hot water into the CH circuit from boiler when on Hot water only. Please note: turn ball valves on pump off, problem solved. Any suggestions or what am I missing?

 

[Nige F]

Gravity check valve on heating circuit IF it`s there it`s stuck open..

 

[Peter plumber]

Thanks Nige F. Just checking, is the gravity check valve to be found on the flow pipe on the CH circuit. There is one on the flow pipe, is this the one? Can you recommend how to unstick it? Thanks for the speedy response.

 

[Nige F]

Yes it`s usually on a vertical pipe.......the flow, as you said......generally just a kind of jumper and washer arrangement inside ..the weight of this holds it shut until the pump is turned on .......tap it with a hammer You caught me indoors @ lunch

 

[Peter plumber]

Nige F. Thank again for the help!!!

 

[Nige F]

No problem