Hmmm

[789dave]

Hello All,

I have three rads in my house that are simply not heating at all...

We've recently installed new 3 point valve and whilst doing this drained down the system, refilled and bled all the rads. All works fine - apart from three rads that are furthest from the tank. I think these have not worked for some time, one of the has the drain off valve so - we decided to leave the system on and drain off water from the said valve to see if this would heat the three cold rads - and it worked. But when we close the valve the rads go cold again.

A case of air locks? Could the pump be struggling to get water to these three rads? (one of them is in an extension)

Any thoughts would be great
Cheers
Dave

 

[Slugbabydotcom]

Did you bleed the air from the vent between the 3 port valve and the cylinder?

 

[789dave]

No - I can't see any vent there - would that be an issue?

 

[Slugbabydotcom]

It might reduce the efficiency of the pump if half of the pipe is full of air. After re-reading your post however I think the next move should be to close off all the rads barring one that doesnt work thus using all the power of the pump to re-establish a route through to the troublesome rad. Then open the next rad and close the preceding one. Work through all 3 troublesome rads in this way. If the rads all get hot when you do this then you should be able to keep them that way by balancing the system ie reducing the flow to the hottest rads by adjustment of their lockshield valves.
See how you go with that and post back