Hi, been having problem with my CH system in a house that we've recently moved into. Worcester Bosch 34CDi combi, 12 rads, system is 2yrs old all piped in plastic.
Long story, two rads downstairs dont get hot, one tepid one cold... completely bled all the air out, balanced up the system as best I can, no success
Through a process of rigourous elimination I've isolated the problem. Basically with all other rads shut off, just these two on full with lockshields fully open, the boiler short cycles and the rads still dont warm up, so I reasoned it must be a blockage of some sort. Both lockshields have drain cocks on them.
If I shut the TRV's and open the lockshields fully, then open the drain cock on either rad, the water doesn't gush out at system pressure, it just runs slowly... If I then open the TRV it gushes out fast and plentiful.
If I try this on any other rad with a drain cock on the lockshield, it gushes out if either the TRV or the lockshield are opened.
So the problem is either in the return pipe from the rads to the manifold or the lockshield isn't opening (or is blocked)
Does this sound plausible ??
Thanks
Mat
Long story, two rads downstairs dont get hot, one tepid one cold... completely bled all the air out, balanced up the system as best I can, no success
Through a process of rigourous elimination I've isolated the problem. Basically with all other rads shut off, just these two on full with lockshields fully open, the boiler short cycles and the rads still dont warm up, so I reasoned it must be a blockage of some sort. Both lockshields have drain cocks on them.
If I shut the TRV's and open the lockshields fully, then open the drain cock on either rad, the water doesn't gush out at system pressure, it just runs slowly... If I then open the TRV it gushes out fast and plentiful.
If I try this on any other rad with a drain cock on the lockshield, it gushes out if either the TRV or the lockshield are opened.
So the problem is either in the return pipe from the rads to the manifold or the lockshield isn't opening (or is blocked)
Does this sound plausible ??
Thanks
Mat