Heating system pitching

[enizzle19]

Hi guys, my grandfather's heating system has been working away no problem for 30 years, a few weeks ago the ballcock in the feed and expansion tank stuck and the system began to run dry he noticed that the upstairs rads were not heating as they were empty obviously, he freed up the ballcock and when the system refilled one of his rads has become slow to warm up and is warm at best and was always red hot beforehand. I assume the pipes to this rad have become airlocked despite the rad having water at the bleed key. The system is now pitching and never had done this before. My question is can this rad loop being airlocked cause the pitching in the attic? I think the vent pipe is coming off the pipes that supply the now dull radiator. Most pipework is hidden so hard to know what's what. Thanks

 

[JohnD]

What is "pitching?"

 

[Madrab]

I think the bigger concern is that that the f&e cistern emptied and so did the rads!

When you say pitching, are you talking about pumping over? There may be a restriction in the pipework.

 

[enizzle19]

Pitching is when the vent pipe has water passing through into the f&e tank or pumping over, the ballcock has been replaced so should not empty again, my question is would an airlock cause the pitching? Would that be enough of a restriction?

 

[denso13]

would an airlock cause the pitching?

Unlikely, the radiator may not work but an airlock on its own won't cause pumping over into the cistern.