Shreaking sound from Grundfos pump after refilling system!

Hi,

Just removed a heated rail from the on-suite, both pipes isolated, fitting new rail later, and system refilled. Temperature got upto around 34 degrees and Grundfos pump started screaming. Extremely alarming so shut entire system off. The Grundfos pump is the one that says '"primary return to boiler!

Just tried venting at the "cold feed and expansion, I thought originally the system had refilled but after venting only for a few seconds the system started filling up with water again. System switched on again and now temperature is at 28 degrees. Is it safe to try again or should I switch off and call an engineer? Problem is I need to fit new heated towel rail in a few days and will have to drain the system again!

Can anyone please advise!

Many thanks

Your system has not refilled. I made this mistake a number of years ago and ended up burning out the boiler pump. I solved it by removing the screw in the bleed valve in the feed line and cleaning the crud out. The BM would then fill up much more quickly.

Basically just make sure you don't switch it on until the BM stops taking water from the header tank.

If you are fitting a towel rail that needs new valves, why not just plug the system, change one valve and then change the other?

Hi and thank you very much for your reply and assistance, how do I plug the system as this has to better than emptying the entire system and all that water? I looked but couldn't find any isolation valves etc?

Many many thanks

Pop a bung in the Feed and Expansion pipes and drain a bit out. Should create a vacuum that stops it all coming out

Sounds a good idea and I'll give it a try, again many thanks.