I'm hoping someone can offer some wisdom here-whilst working on a property i was asked to look at the CH system-its a glowworm spacesaver 30 installed in 84,all rads are controlled by trv's bar one in the bathroom,microbore pipe feeds to rads(10mm),honeywell st699b controller and roomstat in hallway.innitially the customer mentioned that the pump was making a noise and lack of heating downstairs-upstairs ok-so i added a sludge cleaner to the system and flushed out,changed pump and 3 way valve at the same time(as it was semi siezed),the system fired up straight away then cut out approx 5 mins later,i've had probs bleading systems like these locally so we re bled n tried again-little improvement but then again cuts out-suspecting the room stat i swapped it for a new one and now a lot better,house warms up,hot rads downstairs but the boiler still cuts out before the 3 rooms below are as hot as rooms upstairs-whats the chances of the boiler stat being faulty?,programmer fault??,and i was always told roomstats not needed if using trv's-the hallway is about 22 degrees constant-downstairs rooms about 17/18-i'm not sure now if i've been told the whole story and customer has said the boiler been like that for a long time,i've checked most things over and everthing appears fine-anyone got any ideas??