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Hello everyone. This is my first post on here so please excuse if I'm not au fait with the procedure - I'm not even sure if I'm posting in the correct place, but I'm sure someone will put me straight soon enough 
About me - I'm not a plumber, I'm a chippie and only resort to doing plumbing when I have no other option - plumbers seem to be really hard to get hold of, especially just now, and the job I was tackling today I felt, could (and did, in the event,) prove to be a bit time consuming. I usually do the plumbing part (i.e. the sink and waste etc.,) when I have a kitchen to fit, but don't normally get involved in heating systems these days because obviously I can't touch boilers, and my joinery work rarely involves me having to move radiators etc. On the fairly rare occasions when I have gone against my instincts and done them myself, I've had nightmare situations in the past with the cores of isovalves having shot out of the valve, stop taps passing, etc., etc... you know the score, I'm sure... so I usually leave it to those who have the experience and the patience. But - it was at my son's house, I'm on holiday so it wasn't a problem.
He had tiled his bathroom about a year ago and I'd taken the towel radiator off for him and put a stop end on the TRV and the lockshield. He'd got a new towel radiator, with as near the same fitting centres as possible, but when I came to fit it, there was about 15mm difference. the system is 10mm copper so I thought (with a bit of luck, I'd be able to bend the pipe slightly, to accommodate the new rad. No such luck - the pipes exit the wall, not the floor, with an elbow just where it enters the wall , a spigot of about 75mm, then another elbow to the valves. (looks like either the plumber had got the centres miles out, when he first fixed, or the former householder had had a bigger rad fitted at some point and that was the easiest way to do it - a bit untidy, but it functioned.) As soon as I attempted to (gently) bend the 10mm pipe, the joint at the wall elbow fractured and started seeping.
It's a conventional (or at least partly,) system. I shut off the supply to the expansion tank in the cylinder cupboard, via the isovalve (which promptly started leaking at the core,) shut of all the TRV's and lockshields on the upstairs rads, got a bowl and started to drain what I assumed would be about ten gallons or so, from the expansion tank and the 10mm pipework to the rads... Nearly TWO HOURS later, the water finally slowed and stopped - almost - the isolvalve was also passing, so I had to shut the cold off at the mains. I could only think that maybe all the rad valves were not functioning properly (the TRV's are quite old and don't have a definite 'off' position, as mine do,) and that I'd actually been draining all the upstairs rads.
I drained a couple of gallons out of a downstairs rad, to lower the level so I could shorten one of the spigots and re-solder the joint. (I discovered why the joint had failed - the 10mm pipe exiting the wall had only seated about 2mm in the elbow, so when I attempted to bend the pipework, it had just snapped.)
I shortened the spigot, cleaned out the elbow, hung the rad and loosely assembled the new pipework. When all fitted well, I soldered the joints and tightened up the nuts on the rad tails/valves.
I half expected problems when I re-filled it - and boy, did I get them.
I put a new isovalve on the cw feed, a bottle of Fernox in the expansion tank and started to fill the top half of the system. The water just kept on flowing - the level in the expansion tank didn't start to rise at all, for maybe twenty minutes, and that confirmed what I'd assumed previously - i.e that the whole of the upstairs system had been emptied. I bled the towel rad, then started to go around all the upstairs rads, turning on the valves and opening the bleed valves. Not one had any air in, and none of them were properly cold, as they would have been, had they just been filled.
Eventually the level in the expansion tank rose, and we turned on the boiler and set the thermostat. The boiler fired up and we waited for the system to become hot. And waited... and waited. It took well over forty minutes for the system to become properly warm - as if there was a faulty pump causing the trouble or something. It is (my son says) working OK now - but it troubles me: where was all that water coming from, when I was draining what I assumed was just the expansion tank (probably about 30 gallons or so,) and where did it all go, when I was re-filling it??? The only explanation I could think of (and I didn't want to pursue my line of thinking in that direction!) was that maybe there's a fracture in the heating coil in the cylinder and the cylinder contents had been leaking into the circulation water? I sincerely hope not...
I'll give a brief description of the set -up in the cylinder cupboard now:
There is a cylinder with the heating expansion tank above, which seems to double as an expansion tank for the dhw cylinder, from what I see. There is no 3 port valve; instead, two separate pumps, one for the heating, one for the hot water, wired directly into his hive control system. There seems to be a mains cw feed to the cylinder itself (not absolutely sure about that,) quite a few one way valves by the looks of things, and a couple of bleed screws (which I vented, but no air came out.)
Five pics attached (I hope,) if it helps and I'd be grateful if anyone could throw some light on this set - up - I was completely out of my depth today and for a time was really worried that I wouldn't be able to get the system up and running. I'll feel happier once I understand how it works... Thanks.
About me - I'm not a plumber, I'm a chippie and only resort to doing plumbing when I have no other option - plumbers seem to be really hard to get hold of, especially just now, and the job I was tackling today I felt, could (and did, in the event,) prove to be a bit time consuming. I usually do the plumbing part (i.e. the sink and waste etc.,) when I have a kitchen to fit, but don't normally get involved in heating systems these days because obviously I can't touch boilers, and my joinery work rarely involves me having to move radiators etc. On the fairly rare occasions when I have gone against my instincts and done them myself, I've had nightmare situations in the past with the cores of isovalves having shot out of the valve, stop taps passing, etc., etc... you know the score, I'm sure... so I usually leave it to those who have the experience and the patience. But - it was at my son's house, I'm on holiday so it wasn't a problem.
He had tiled his bathroom about a year ago and I'd taken the towel radiator off for him and put a stop end on the TRV and the lockshield. He'd got a new towel radiator, with as near the same fitting centres as possible, but when I came to fit it, there was about 15mm difference. the system is 10mm copper so I thought (with a bit of luck, I'd be able to bend the pipe slightly, to accommodate the new rad. No such luck - the pipes exit the wall, not the floor, with an elbow just where it enters the wall , a spigot of about 75mm, then another elbow to the valves. (looks like either the plumber had got the centres miles out, when he first fixed, or the former householder had had a bigger rad fitted at some point and that was the easiest way to do it - a bit untidy, but it functioned.) As soon as I attempted to (gently) bend the 10mm pipe, the joint at the wall elbow fractured and started seeping.
It's a conventional (or at least partly,) system. I shut off the supply to the expansion tank in the cylinder cupboard, via the isovalve (which promptly started leaking at the core,) shut of all the TRV's and lockshields on the upstairs rads, got a bowl and started to drain what I assumed would be about ten gallons or so, from the expansion tank and the 10mm pipework to the rads... Nearly TWO HOURS later, the water finally slowed and stopped - almost - the isolvalve was also passing, so I had to shut the cold off at the mains. I could only think that maybe all the rad valves were not functioning properly (the TRV's are quite old and don't have a definite 'off' position, as mine do,) and that I'd actually been draining all the upstairs rads.
I drained a couple of gallons out of a downstairs rad, to lower the level so I could shorten one of the spigots and re-solder the joint. (I discovered why the joint had failed - the 10mm pipe exiting the wall had only seated about 2mm in the elbow, so when I attempted to bend the pipework, it had just snapped.)
I shortened the spigot, cleaned out the elbow, hung the rad and loosely assembled the new pipework. When all fitted well, I soldered the joints and tightened up the nuts on the rad tails/valves.
I half expected problems when I re-filled it - and boy, did I get them.
I put a new isovalve on the cw feed, a bottle of Fernox in the expansion tank and started to fill the top half of the system. The water just kept on flowing - the level in the expansion tank didn't start to rise at all, for maybe twenty minutes, and that confirmed what I'd assumed previously - i.e that the whole of the upstairs system had been emptied. I bled the towel rad, then started to go around all the upstairs rads, turning on the valves and opening the bleed valves. Not one had any air in, and none of them were properly cold, as they would have been, had they just been filled.
Eventually the level in the expansion tank rose, and we turned on the boiler and set the thermostat. The boiler fired up and we waited for the system to become hot. And waited... and waited. It took well over forty minutes for the system to become properly warm - as if there was a faulty pump causing the trouble or something. It is (my son says) working OK now - but it troubles me: where was all that water coming from, when I was draining what I assumed was just the expansion tank (probably about 30 gallons or so,) and where did it all go, when I was re-filling it??? The only explanation I could think of (and I didn't want to pursue my line of thinking in that direction!) was that maybe there's a fracture in the heating coil in the cylinder and the cylinder contents had been leaking into the circulation water? I sincerely hope not...
I'll give a brief description of the set -up in the cylinder cupboard now:
There is a cylinder with the heating expansion tank above, which seems to double as an expansion tank for the dhw cylinder, from what I see. There is no 3 port valve; instead, two separate pumps, one for the heating, one for the hot water, wired directly into his hive control system. There seems to be a mains cw feed to the cylinder itself (not absolutely sure about that,) quite a few one way valves by the looks of things, and a couple of bleed screws (which I vented, but no air came out.)
Five pics attached (I hope,) if it helps and I'd be grateful if anyone could throw some light on this set - up - I was completely out of my depth today and for a time was really worried that I wouldn't be able to get the system up and running. I'll feel happier once I understand how it works... Thanks.
