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I'm having ongoing issues with my boiler heating water...
I have an Open Vented system with the Cold Water Tank and F&E Tank in the loft, the Hot Water cylinder in the Airing Cupboard and a floor standing Potterton Promax FSB 30 HE Boiler in the Kitchen.
The boiler is set to come on for twenty minutes each morning to heat the water. Usually this works as expected and I hear the boiler come on and the pipes knock for around two minutes (which I assume is the pipes expanding slightly, they've always done that). Then everything settles down, the boiler runs quietly and I have piping hot water.
Recently instead of the pipes just making a knocking sound for two minutes, they now do it every 15 seconds so it's almost as though the boiler is kicking in, stopping and starting repeatedly even though that's not actually what's happening, i.e., the boiler remains on for the full 20 minutes.
Long story short I have hot but not properly hot water, i.e., I can run a bath using only the hot water and no cold water and it's just about the right temperature. Previously I would need to run a mix of hot and cold water. If I fill the bathroom sink, for a shave the water feels luke warm.
When the problem first started the boiler was using noticeably less gas to heat the water. My plumber suggested having the system MagnaCleansed to clear out any sludge. The heating system dates from the 1970's though every element apart from the pipework has been replaced, i.e., hot water cylinder, cold water tank and the boiler is now around ten years old.
The hot water tank was fitted about a year ago and I had a MagnaCleanse about a month ago which initially seemed to fix the hot water problem but now its back again, this time the energy usage is normal, the boiler isn't switching itself off, it's just not heating the water very well.
The thermostat on the hot water cylinder is set to 65 degrees (as set by the plumber) though it used to be fine at 60 degrees.
The heating appears to be absolutely fine, all radiators (of which there are only three) are red hot top and bottom.
When the boiler switches off after 20 minutes I hear what sounds like a flow of water flowing through the pipes for around 5 seconds, it almost sounds like water is briefly travelling back in the opposite direction, I don't know how else to describe it.
Anyway, I'm desperately trying to understand possible causes for the water not heating properly. The taps are not spluttering so there are no obvious signs of an airlock but I don't know if an airlock could manifest itself in other ways and only affect the hot water?
1. Could there be a problem with the hot water cylinder, despite only being one year old?
2. Could there be a problem with the boiler itself and if so what could likely problems be bearing in mind the heating is fine and there are no error lights coming on?
I would be eternally grateful if anyone can either suggest things I could try safely or suggest possible causes for the symptoms described above so I at least know what I need to do.
Repeated plumber visits don't seem to have identified the problem since it keeps reoccurring.
Many thanks
I have an Open Vented system with the Cold Water Tank and F&E Tank in the loft, the Hot Water cylinder in the Airing Cupboard and a floor standing Potterton Promax FSB 30 HE Boiler in the Kitchen.
The boiler is set to come on for twenty minutes each morning to heat the water. Usually this works as expected and I hear the boiler come on and the pipes knock for around two minutes (which I assume is the pipes expanding slightly, they've always done that). Then everything settles down, the boiler runs quietly and I have piping hot water.
Recently instead of the pipes just making a knocking sound for two minutes, they now do it every 15 seconds so it's almost as though the boiler is kicking in, stopping and starting repeatedly even though that's not actually what's happening, i.e., the boiler remains on for the full 20 minutes.
Long story short I have hot but not properly hot water, i.e., I can run a bath using only the hot water and no cold water and it's just about the right temperature. Previously I would need to run a mix of hot and cold water. If I fill the bathroom sink, for a shave the water feels luke warm.
When the problem first started the boiler was using noticeably less gas to heat the water. My plumber suggested having the system MagnaCleansed to clear out any sludge. The heating system dates from the 1970's though every element apart from the pipework has been replaced, i.e., hot water cylinder, cold water tank and the boiler is now around ten years old.
The hot water tank was fitted about a year ago and I had a MagnaCleanse about a month ago which initially seemed to fix the hot water problem but now its back again, this time the energy usage is normal, the boiler isn't switching itself off, it's just not heating the water very well.
The thermostat on the hot water cylinder is set to 65 degrees (as set by the plumber) though it used to be fine at 60 degrees.
The heating appears to be absolutely fine, all radiators (of which there are only three) are red hot top and bottom.
When the boiler switches off after 20 minutes I hear what sounds like a flow of water flowing through the pipes for around 5 seconds, it almost sounds like water is briefly travelling back in the opposite direction, I don't know how else to describe it.
Anyway, I'm desperately trying to understand possible causes for the water not heating properly. The taps are not spluttering so there are no obvious signs of an airlock but I don't know if an airlock could manifest itself in other ways and only affect the hot water?
1. Could there be a problem with the hot water cylinder, despite only being one year old?
2. Could there be a problem with the boiler itself and if so what could likely problems be bearing in mind the heating is fine and there are no error lights coming on?
I would be eternally grateful if anyone can either suggest things I could try safely or suggest possible causes for the symptoms described above so I at least know what I need to do.
Repeated plumber visits don't seem to have identified the problem since it keeps reoccurring.
Many thanks
