Cold feed blocked or faulty pump.

Hi
Having been let down by local plumber who said I needed a new 3 way zone vlave I have fitted the valve myself. Having drained the small bore system with the rads isolated at both ends, fitting the zone valve and checking all connections the system did not seem to refill. I attempted to back feed the sytem by connecteing cold supply to the rad where I drained the system and rads seemed to fill and eventually I had water feeding into the header tank. Then shuting off supply and starting the boiler the hot water is OK but the rads do not heat properly. 2 out of 4 upstairs get warm, 1 of 3 downstairs gets hot, one gets luke warm, one nothing.
Could this all be a problem with the pump?
The pump is turning, and the zone valve operates according to the control.
Help would be appreciated.

To check if it is a filling problem (blockages are very common).

If you tie up the float in the header tank, or turn of the supply to it, and draw off a bucket of water from the drain, does the water level in the header tank drop by a corresponding amount?





(you can tip the bucket back in afterwads to conserve any corrosion inhibitor fluid)

JohnD

Thanks for suggestion. I will try it out.

sounds like a blocked cold feed, you can back fill it, bleed it back fill it some more etc etc. Best thing to do is to cut out the t connector where the feed enters the system and replace it. Try tapping it first to see if you can allow a little water through to drain it.....otherwise you will need to bung the system.

I don't think there's an FAQ, but if you like reading, have a look at

//www.diynot.com/forums/viewtopic.php?t=37114&highlight=

and its references.