Since moving into a new house several months ago Im suffering from cold (cool) radiators in some of the downstairs rooms (3 out of 5 are problematic). Its a normal gravity fed system. This is what I have done so far:
All rads changed for new.
New TRV's and lockshields
System flushed (but not power flushed), cleaner installed (for few weeks) , flushed and refilled with inhibitor.
Magnetic filter cleaned and recleaned again after several weeks
Radiators balanced.
System bled.
Boiler serviced
New Pump
Most of the time the problem 3 radiators are only slightly warm but occasionally one will get hot but not for long.
Have tried closing off all the good rads and leaving the problem ones fully open and they do improve just a little.
Pipe on inlet side of the rads is red hot but cool on outlet side. Even tried slackening off the valve on the outlet side to make sure there was flow and there is (but maybe not enough?)
so Im running out of ideas now... surely if there was a blockage then the problem rads would never heat?
All rads changed for new.
New TRV's and lockshields
System flushed (but not power flushed), cleaner installed (for few weeks) , flushed and refilled with inhibitor.
Magnetic filter cleaned and recleaned again after several weeks
Radiators balanced.
System bled.
Boiler serviced
New Pump
Most of the time the problem 3 radiators are only slightly warm but occasionally one will get hot but not for long.
Have tried closing off all the good rads and leaving the problem ones fully open and they do improve just a little.
Pipe on inlet side of the rads is red hot but cool on outlet side. Even tried slackening off the valve on the outlet side to make sure there was flow and there is (but maybe not enough?)
so Im running out of ideas now... surely if there was a blockage then the problem rads would never heat?