I noticed that when I removed the gate valve, the pipe was completely
full of sludge - I would have thought the Fornox sludge remover would
have fixed this! Anyway I've clean the pipe as best as I could then
ran the pump on full. My system now gets to 65 degrees, a 15 degree
improvement!!!

Thanks for the advice!
(Danny) wrote in message . com...
Thanks for the advice. I will give the automatic by-pass valve a go
and let you know how I get on!

Again, thanks for Roger, Chrisian for all of your help

Regards,

Danny

"Christian McArdle" wrote in message et...
Thats right, it only trips when the CH motorised valve is closed. I
fully opened the by-pass valve, with the CH circuit off, I noticed
that the water wasn't passing through the by-pass valve, massive
temperature difference on either side of the valve.

Sounds knackered, just like most gate valves ten minutes after installation.
When you replace it, use an "Automatic Bypass Valve" instead of a gate
valve. This stays closed when the zone valves are open, but when they close,
it detects the pressure differential from the pump and opens fully. This
way, you get an effective bypass and no short circuit when the system is
actually working.

Christian.