I have a 12 radiator house serviced by a 22+ year-old Potterton Profile boiler. I have what seems to be a compound heating issue that two separate and quite competent (I believe) plumbers have been unable to diagnose or so far repair. Here is the sequence of events:
A couple of years ago, we noticed that the radiator heat output was reduced when the central heating was on. Not long after that, our CH pump failed, and our plumber replaced it with a Grundfos UPS3 15-50/65. This didn't solve the heat reduction issue though.
Over time, the problem worsened, and during this last winter the heating would only work with the hot water switched off. No output at all whenever the HW was on.
We went on holiday in March for two weeks and turned off the hot water / left the CH to come on periodically on a low setting. When we returned, the heating downstairs was almost non-existent. Our plumber looked at this, and by the time he returned a week later to try and fix it, there was no heat anywhere except 2 x towel rails located near the hot water cylinder. He thought some piping connected to or near the pump was sludged up, so he replaced it. He was correct, but replacing didn't fix it. He thought that wide-scale sludge was at the root of the problem, and he recommended power flushing. He doesn't do power flushing so we called in plumber B.
Plumber B power flushed the system, refilled it and fired everything up. No change. He thought there was some hardened sludge in a return pipe that the power flush hadn't shifted, and he managed to clear that manually. Still no change. He then thought that the Grundfos pump wasn't working correctly, so he fitted a new 15-60 pump (not Grundfos). Again, this made no difference. He then filled the system with Sentinel X400 descaler, and suggested leaving it for 3 weeks to see if there was any improvement.
The situation I now find myself in, is that if I leave all radiator valves open, I still only get heat to the towel rails. If I turn off the towel rails, I get heat flowing to the upstairs radiators. If I turn off those as well, I get heat to some of the downstairs radiators to varying degrees. If I then start turning off the hotter ones, then the heat does get to all of the others, with one or two where it is only just warm. The hot water is mainly ok, although it does now seem to take longer to heat up than it used to. As before, turning on the hot water kills off the central heating.
As far as the boiler is concerned, it only comes on for short periods - a minute or two every 5-10 minutes.
My only issue with the plumbers is that they are trying to solve the problem by trial and error, and this is becoming expensive. Especially as the next step suggested is to individually flush out each radiator. Ideally I'd like to see something tangible being diagnosed, and then tackling that. I accept we have an old boiler that could do with replacing, but a) no-one has suggested that this is the cause of this issue, and b) I don't want a new boiler to be impacted by a problem that lies elsewhere within the system.
Any views on this short message?
A couple of years ago, we noticed that the radiator heat output was reduced when the central heating was on. Not long after that, our CH pump failed, and our plumber replaced it with a Grundfos UPS3 15-50/65. This didn't solve the heat reduction issue though.
Over time, the problem worsened, and during this last winter the heating would only work with the hot water switched off. No output at all whenever the HW was on.
We went on holiday in March for two weeks and turned off the hot water / left the CH to come on periodically on a low setting. When we returned, the heating downstairs was almost non-existent. Our plumber looked at this, and by the time he returned a week later to try and fix it, there was no heat anywhere except 2 x towel rails located near the hot water cylinder. He thought some piping connected to or near the pump was sludged up, so he replaced it. He was correct, but replacing didn't fix it. He thought that wide-scale sludge was at the root of the problem, and he recommended power flushing. He doesn't do power flushing so we called in plumber B.
Plumber B power flushed the system, refilled it and fired everything up. No change. He thought there was some hardened sludge in a return pipe that the power flush hadn't shifted, and he managed to clear that manually. Still no change. He then thought that the Grundfos pump wasn't working correctly, so he fitted a new 15-60 pump (not Grundfos). Again, this made no difference. He then filled the system with Sentinel X400 descaler, and suggested leaving it for 3 weeks to see if there was any improvement.
The situation I now find myself in, is that if I leave all radiator valves open, I still only get heat to the towel rails. If I turn off the towel rails, I get heat flowing to the upstairs radiators. If I turn off those as well, I get heat to some of the downstairs radiators to varying degrees. If I then start turning off the hotter ones, then the heat does get to all of the others, with one or two where it is only just warm. The hot water is mainly ok, although it does now seem to take longer to heat up than it used to. As before, turning on the hot water kills off the central heating.
As far as the boiler is concerned, it only comes on for short periods - a minute or two every 5-10 minutes.
My only issue with the plumbers is that they are trying to solve the problem by trial and error, and this is becoming expensive. Especially as the next step suggested is to individually flush out each radiator. Ideally I'd like to see something tangible being diagnosed, and then tackling that. I accept we have an old boiler that could do with replacing, but a) no-one has suggested that this is the cause of this issue, and b) I don't want a new boiler to be impacted by a problem that lies elsewhere within the system.
Any views on this short message?
