Air lock?

[reggie09]

hi all, just done a boiler swap and have a little problem which i think is an air lock, boiler all checking out ok works fine(heat only boiler) the problem i have is 3 out of 8 rads are clap cold! have bled entire system and have water in all rads but whats throwing me is when we flushed system out it was really caked up and the pump was seized, we freed it off and is working but how well im not sure, could i have a problem with pump also? when i take flow and return out of the rad valves no flow on any of the 3 rads, any info welcomed.

 

[Centralheatking]

THe pump motor can become detatched from the impellor so it seems to be working but no water circulates.

centralheatking

 

[reggie09]

ive had the pump off and impellor is working as should be from what i can see, other than shutting other rads off to try and shift any air i cant think of anything else but to drain down again.

 

[Centralheatking]

Give it a shot of mains pressure if its a conventional system - connect cold main to drain point using jubilee clip on drain. Give it several squirts of mains if you put too much in the o/flow on the f& e will operate and blip the pump on and off at same time.

centralheatking

 

[fuzzy]

my favourite is to try to drag water through drain offs, it works most the time