Problem is that 2 radiators upstairs are cold...
When the boiler was installed I had them both replaced, single panel for a double inc replacing the TRVs, as they had always been much colder than the rest. Both seem to work fine initially, but over the last year have gradually started to get colder and colder (when the system is on) until they are now totally cold.
Not a clue what is wrong, but these are the things I observed:
- Original system (inc. radiators) is plumbed using 15mm copper. - We had an extension built several years ago, and several radiators were added. For those, the pipes running into/from the new radiators (i.e. last ~0.5m) are flexi 10mm pipes (the lazy bu**ers couldn't be bothered with soldering straight joins...). - In the case of the two cold radiators, the 10mm pipes attaching them to the 15mm pipes are much longer - approx. final 2-3m. - When system is on. the feed into one of the cold radiators is warmish, outlet is cold. For the other radiator both pipes are cold.
Any idea what is going on here?