Apologies in advance for the length of this post, but I'm trying to anticipate everything I'll be asked.
Our bathrooom was refitted last week and its standard radiator replaced with a towel radiator (exactly the same as we had done in the en-suite the previous year). Not long after the system was refilled at the end of the job, water started steadily dripping out of the cold water tank's overflow pipe under the gutter of the house. The plumber who fitted the bathroom seems to be stumped and I can't see a logical reason either, so over to you. Here are the details:
Open vented, indirect system with a cold water tank and a feed and expansion tank next to each other in the loft. Directly beneath them in the airing cupboard on the second floor is the hot water cylinder, pump, pipework etc.
Below again, on the first floor, is the bathroom itself, and the boiler (Ideal Icos) is on the ground floor. The bathroom has a thermostatic shower/mixer tap, unpumped. The plumber told me when he was doing the bathroom that that tap is fed by mains cold and gravity hot, (which has always been the case), which he thought unusual. That shower's always been great, and still is. The en-suite above has a pump to its shower.
The symptoms of the problem are that over a period of around 7 hours, warm water enters the cold water tank and causes it to overflow. If I drain it so it's below the level of the overflow, which I do by isolating its mains cold supply then running the bath's hot tap for 10-15 mins, obviously that temporarily cures the problem but the level creeps back up.
This happens regardless of whether the CH/HW system is active or not - so I can drain the tank before going to bed, and with everything off for the night and no water being drawn from any outlet, when I get up in the morning the tank will be overflowing again. As I say, the water in the cold water tank is warm, and I've narrowed the source to the pipe which leads from the tank to the hot water cylinder, which presumably should only ever have cold going down, not hot coming up. The only other possibilities would be the vent pipe, which enters at the top of the CW tank (not this, because I floated a plastic bowl under it, left it all night and in the morning it was still empty and the water had still risen) and the cold water mains inlet (not this, because I've left that switched off via its isolation valve).
So hot water is either being pushed or sucked up the pipe into the tank, but with the system apparently doing nothing. How's this possible? Could it be the pump? The plumber did also note that the pump is constantly humming, spinning quietly even when there's no demand for HW/CW, but that's always been the case and this only started happening after the radiators were drained and refilled. I wondered about air in the system - I've bled all the radiators and that's made no difference. Could it be something to do with the boiler?
Anyway. If anyone has any ideas I'd love to hear them. Thanks in advance...
Our bathrooom was refitted last week and its standard radiator replaced with a towel radiator (exactly the same as we had done in the en-suite the previous year). Not long after the system was refilled at the end of the job, water started steadily dripping out of the cold water tank's overflow pipe under the gutter of the house. The plumber who fitted the bathroom seems to be stumped and I can't see a logical reason either, so over to you. Here are the details:
Open vented, indirect system with a cold water tank and a feed and expansion tank next to each other in the loft. Directly beneath them in the airing cupboard on the second floor is the hot water cylinder, pump, pipework etc.
Below again, on the first floor, is the bathroom itself, and the boiler (Ideal Icos) is on the ground floor. The bathroom has a thermostatic shower/mixer tap, unpumped. The plumber told me when he was doing the bathroom that that tap is fed by mains cold and gravity hot, (which has always been the case), which he thought unusual. That shower's always been great, and still is. The en-suite above has a pump to its shower.
The symptoms of the problem are that over a period of around 7 hours, warm water enters the cold water tank and causes it to overflow. If I drain it so it's below the level of the overflow, which I do by isolating its mains cold supply then running the bath's hot tap for 10-15 mins, obviously that temporarily cures the problem but the level creeps back up.
This happens regardless of whether the CH/HW system is active or not - so I can drain the tank before going to bed, and with everything off for the night and no water being drawn from any outlet, when I get up in the morning the tank will be overflowing again. As I say, the water in the cold water tank is warm, and I've narrowed the source to the pipe which leads from the tank to the hot water cylinder, which presumably should only ever have cold going down, not hot coming up. The only other possibilities would be the vent pipe, which enters at the top of the CW tank (not this, because I floated a plastic bowl under it, left it all night and in the morning it was still empty and the water had still risen) and the cold water mains inlet (not this, because I've left that switched off via its isolation valve).
So hot water is either being pushed or sucked up the pipe into the tank, but with the system apparently doing nothing. How's this possible? Could it be the pump? The plumber did also note that the pump is constantly humming, spinning quietly even when there's no demand for HW/CW, but that's always been the case and this only started happening after the radiators were drained and refilled. I wondered about air in the system - I've bled all the radiators and that's made no difference. Could it be something to do with the boiler?
Anyway. If anyone has any ideas I'd love to hear them. Thanks in advance...
computer playing up
