Potterton Profile e60

[andypest]

When my boiler switches off after heat is satisfied recently there seems to be alot of gurgling and the sound of rushing water going into the boiler, this goes on for a few minutes. Is this normal ????
I am also getting loud bangs or knocks from around the house at different times of the day, is this an airlock. I have drained the system and bled all the radiator.
Any ideas anyone

 

[namsag]

Sounds like the boiler stat is on it way out and not cutting off at correct temp and boiler getting far too hot . mind you profile has an over heat safety stat on it that should have tripped out

 

[andypest]

Both stats in the boiler were replacred about 2 months ago because it was tripping off. The gurggeling and rushing water noise seems to be worse since then. the boiler does not trip off any more...
British gas did a survey on the boiler about 2 months ago and recommended an air seperator for approx £200 would you recommend having this installed and is the price ok or am i being ripped off