I had a new boiler fitted yesterday as well as new thermostatic valves on various radiators. My (corgi registered) plumber also installed a drainage valve (which the system lacked) on one of the radiator pipes using a copper push-fit t-joint. All seemed fine over night then this morning I had a look at the drainage valve, gave it a twist and it came out of the t-joint. I could push it back in again - it is perfectly water tight - but it doesn't take much pressure for it to come out and I'm worried about leaving the house in case it jumps out while I'm away. The plumber has so far failed to get back to me to talk about it, but the twist in the tale is that I insisted on him using a copper push-fit fitting (which he said he hated!) rather than the lumpy plastic one he was going to use, and went to Wickes to buy it (location of the valve is such that a soldered or compression fitting isn't an option). My question is, is this a fault with the pushfit t-joint (which my plumber might well claim), or with the standard brass drainage valve which is pushed into it, or is it neither - perhaps these fitting aren't designed to be used with the brass drainage valve (which my plumber is not likely to admit he didn't know)?
Any thoughts would be appreciated - in the meantime I'll be tying the joint on with a bit of string!
Mark