I'll try and be as succinct as possible but apologies in advance for all the text! Here is the order of events:
1. In the beginning…whenever our water was being heated up the radiators always came on a bit. I assumed this was normal.
2. In June, our boiler started to not heat water all the time resulting in the overheating light switching on. I would turn the boiler off and then on again to clear the light after which it would work for a day or two and then it would happen again.
3. I called a plumber who thought that it was a problem with our pump. He said he could replace the pump or do a power flush through the system as he thought the cause could be gunk in the pipes. We opted for the power flush only. (He also said that this pump configuration was unusual and not used anymore).
4. After the power flush the overheating light never come on so I presume this problem was fixed. The plumber said that lots of gunk came out the system (he showed me) and thought it possibly hadn't ever been done (the boiler has been in the house for ~18 years). He was confused that the radiators were heating up when the water was on as he said this shouldn't happen. I said it has always happened to a degree.
5. After a couple of days I noticed the radiators were much hotter now when the water was on. They were at the same temperature as when the central heating was on now even though it was off. I called the plumber. He said that there must be some kind of piping issue where the pipes have been connected incorrectly. I asked him for a quote to fix but never heard back. In the meantime, on his advice. I turned off all the radiators values which solve the issue in the short term.
6. Fast forward to this Monday. My wife tells me the pipes were making lots of banging noises in the night when the water should have been heating up. There is also no hot water. Since then I have experimented a couple of times with turning the water on and when I do the boiler does fire up but turns off after a short time as, presumably, it isn’t getting any water. However, if I turn the central heating on I DO get hot water! I have tested this the last two evenings and this does indeed seem to be the case.
Strange: That originally the radiators would get hot when the water was heating up but now I only get water when the radiators are on.
Cause: I am thinking this must be a pump issue. When I turn the hot water on it is as though there isn’t any water to pump but I guess there must be for the radiators to work. The pump in use is a UPP 15/50 Pump Plan (http://www.plumbcenter.co.uk/en/archive/heating-archive/pumps-archive/grundfos-upp15-50-pump-plan-152613). I have spent the evening trying to figure out the central heating/plumbing system in general as it is the one part of the house that I have never fully understood. Please excuse my laughable drawing attachment. The items inside the green square represent stuff I cannot trace but is how I assume it to be.
So I guess my questions are:
1. Could the pump be faulty for the hot water but not for the central heating?
2. Surely it can’t be faulty if it still pumps water when the central heating is on?
3. Could it be air in the system?
4. Is it possible for radiators to come on even hotter after a power flush when the water is on or did the plumber change/set/do something incorrectly on the pump?
5. Is this pump really unusual or did the plumber just not know about it?
6. I find it tough to believe that the pipework is incorrect. It seems much more likely to me that there is an issue with the pump….?
Any and all advice is appreciated. Thanks in advance for reading this mass of text. Craig.
1. In the beginning…whenever our water was being heated up the radiators always came on a bit. I assumed this was normal.
2. In June, our boiler started to not heat water all the time resulting in the overheating light switching on. I would turn the boiler off and then on again to clear the light after which it would work for a day or two and then it would happen again.
3. I called a plumber who thought that it was a problem with our pump. He said he could replace the pump or do a power flush through the system as he thought the cause could be gunk in the pipes. We opted for the power flush only. (He also said that this pump configuration was unusual and not used anymore).
4. After the power flush the overheating light never come on so I presume this problem was fixed. The plumber said that lots of gunk came out the system (he showed me) and thought it possibly hadn't ever been done (the boiler has been in the house for ~18 years). He was confused that the radiators were heating up when the water was on as he said this shouldn't happen. I said it has always happened to a degree.
5. After a couple of days I noticed the radiators were much hotter now when the water was on. They were at the same temperature as when the central heating was on now even though it was off. I called the plumber. He said that there must be some kind of piping issue where the pipes have been connected incorrectly. I asked him for a quote to fix but never heard back. In the meantime, on his advice. I turned off all the radiators values which solve the issue in the short term.
6. Fast forward to this Monday. My wife tells me the pipes were making lots of banging noises in the night when the water should have been heating up. There is also no hot water. Since then I have experimented a couple of times with turning the water on and when I do the boiler does fire up but turns off after a short time as, presumably, it isn’t getting any water. However, if I turn the central heating on I DO get hot water! I have tested this the last two evenings and this does indeed seem to be the case.
Strange: That originally the radiators would get hot when the water was heating up but now I only get water when the radiators are on.
Cause: I am thinking this must be a pump issue. When I turn the hot water on it is as though there isn’t any water to pump but I guess there must be for the radiators to work. The pump in use is a UPP 15/50 Pump Plan (http://www.plumbcenter.co.uk/en/archive/heating-archive/pumps-archive/grundfos-upp15-50-pump-plan-152613). I have spent the evening trying to figure out the central heating/plumbing system in general as it is the one part of the house that I have never fully understood. Please excuse my laughable drawing attachment. The items inside the green square represent stuff I cannot trace but is how I assume it to be.
So I guess my questions are:
1. Could the pump be faulty for the hot water but not for the central heating?
2. Surely it can’t be faulty if it still pumps water when the central heating is on?
3. Could it be air in the system?
4. Is it possible for radiators to come on even hotter after a power flush when the water is on or did the plumber change/set/do something incorrectly on the pump?
5. Is this pump really unusual or did the plumber just not know about it?
6. I find it tough to believe that the pipework is incorrect. It seems much more likely to me that there is an issue with the pump….?
Any and all advice is appreciated. Thanks in advance for reading this mass of text. Craig.