Just before Christmas my partners central heating system in her early 60's bungalow started losing pressure. During the day the pressure was fine but overnight it would drop below the minimum and need recharging in the morning.
To cut a long story short I couldn't find a significant leak despite extensive searching including isolating the boiler and pressure testing it and the rest of the system separately. Not wanting a very cold Christmas/New Year I resorted to using Fernox F4 leak sealer. I'm aware of the downside of using leak sealer but the boiler, installed in 2005, is going to be changed this year, so the use of leak sealer was kill or short term cure. The sealer initially worked but then failed but now seems to be holding after doubling the amount used as per Fernox technical support suggestion. The leak is not from the PRV and the condensate discharge is minimal once the boiler is off (about 160ml overnight or nothing). Fernox suggested the problem may be the primary heat exchanger leaking when it's cold but not when hot but the F4 will not resolve this beyond a short period if at all.
It is regarding the boiler change that I've started this thread.
In the 4 years we've been in the property, I've never been able to get a temperature drop across either the boiler or radiators of more than about 2 degs C (except when the rads are heating up from cold) without the boiler short cycling more that it does anyway. BG engineer couldn't either and suggested the boiler (Glowworm 30CXi) was too big and this was probably the reason for lack of temperature drop and short cycling.
Below is a floor plan of the bungalow showing the central heating layout. The 22mm Flow 1 & Return 1 pipes run from the boiler cupboard along the hall to the lounge with a short loop near the lounge doorway then back down the hall (Flow 2 & Return 2) to serve the hall, bedrooms and bathroom.
Running the 22mm pipes back down the hall to serve the hall, bedrooms and bathroom seems odd, a waste of 22mm pipe and inefficient when these rooms could have been connected outside the boiler/meter cupboards. I wonder if the extra 22mm Flow 2 & Return 2 pipes and connection of the hall, bedrooms and bathroom to them were an attempt to mitigate an oversize boiler???
All the pipe insulation is the old lightweight soft sponge type that is either missing or falling apart and needs replacing. The 22mm pipes run along the hall are too close together, even for the existing insulation, so re-insulating them will be difficult unless the new insulation is severely squashed and forced into place. If the new boiler would not need the extra 22mm pipe running back down the hall, could it be removed making enough space for the new insulation and increasing efficiency?
I'd also like to rationalise the pipework where possible and replace the flexible pipes serving the hall rad with copper due to possible rodents under the suspended timber floor.
Any help will be much appreciated.
To cut a long story short I couldn't find a significant leak despite extensive searching including isolating the boiler and pressure testing it and the rest of the system separately. Not wanting a very cold Christmas/New Year I resorted to using Fernox F4 leak sealer. I'm aware of the downside of using leak sealer but the boiler, installed in 2005, is going to be changed this year, so the use of leak sealer was kill or short term cure. The sealer initially worked but then failed but now seems to be holding after doubling the amount used as per Fernox technical support suggestion. The leak is not from the PRV and the condensate discharge is minimal once the boiler is off (about 160ml overnight or nothing). Fernox suggested the problem may be the primary heat exchanger leaking when it's cold but not when hot but the F4 will not resolve this beyond a short period if at all.
It is regarding the boiler change that I've started this thread.
In the 4 years we've been in the property, I've never been able to get a temperature drop across either the boiler or radiators of more than about 2 degs C (except when the rads are heating up from cold) without the boiler short cycling more that it does anyway. BG engineer couldn't either and suggested the boiler (Glowworm 30CXi) was too big and this was probably the reason for lack of temperature drop and short cycling.
Below is a floor plan of the bungalow showing the central heating layout. The 22mm Flow 1 & Return 1 pipes run from the boiler cupboard along the hall to the lounge with a short loop near the lounge doorway then back down the hall (Flow 2 & Return 2) to serve the hall, bedrooms and bathroom.
Running the 22mm pipes back down the hall to serve the hall, bedrooms and bathroom seems odd, a waste of 22mm pipe and inefficient when these rooms could have been connected outside the boiler/meter cupboards. I wonder if the extra 22mm Flow 2 & Return 2 pipes and connection of the hall, bedrooms and bathroom to them were an attempt to mitigate an oversize boiler???
All the pipe insulation is the old lightweight soft sponge type that is either missing or falling apart and needs replacing. The 22mm pipes run along the hall are too close together, even for the existing insulation, so re-insulating them will be difficult unless the new insulation is severely squashed and forced into place. If the new boiler would not need the extra 22mm pipe running back down the hall, could it be removed making enough space for the new insulation and increasing efficiency?
I'd also like to rationalise the pipework where possible and replace the flexible pipes serving the hall rad with copper due to possible rodents under the suspended timber floor.
Any help will be much appreciated.
