Good evening all,
I currently have an issue with my heating system banging. First a technical overview for what it's worth.
Sealed central heating system served from an ideal logic heat 12 boiler. This serves a megaflo HW cylinder and two heating circuits (upstairs/downstairs). Each circuit has a two port motorised valve on it (Danfoss) and the whole system is circulated by a grundfos UPS2 15-50/60. Controller is a Hortsmann Channel plus H37XL. System is pressurised with a 12l BOSS expansion vessel.
So the system has always operated at a high pressure circa 1.8bar for the past two plus years since we moved in (it's a new build home). Never had any issue other than the pipework in the airing cupboard where the HW cylinder/pump is located being noisy when the pump runs, this is probably due to the pump being set at a high speed but I never bothered to drop it down. So a few days ago I noticed that the radiator in the bathroom was cold, I checked that the TRV pin wasn't stuck, which it wasn't then bled the radiator and got a lot of air out of it, the system pressure actually dropped to zero, I then topped it up to about 1.25 bar. Since then I get a loud bang every so often in the airing cupboard, it's an initial bang followed by a sort of bouncing noise.
I've been doing some investigation work and have narrowed it down to when it occurs. When boiler receives a no heat required signal it shuts off, all 2 ports close and the pump carries on running for a few minutes (overrun as you'd expect). When the pump finished the overrun and shuts off I get the bang, the pressure remains constant throughout and the bang seems to come from around the expansion vessel, the pressure gauge on the vessel bounces then drops about 0.2 bar, then slowly climbs back to the previous operating pressure.
Anyone had any experience of this before, is it a faulty vessel, pump issues? I have never come across this before.
Thanks Andy
I currently have an issue with my heating system banging. First a technical overview for what it's worth.
Sealed central heating system served from an ideal logic heat 12 boiler. This serves a megaflo HW cylinder and two heating circuits (upstairs/downstairs). Each circuit has a two port motorised valve on it (Danfoss) and the whole system is circulated by a grundfos UPS2 15-50/60. Controller is a Hortsmann Channel plus H37XL. System is pressurised with a 12l BOSS expansion vessel.
So the system has always operated at a high pressure circa 1.8bar for the past two plus years since we moved in (it's a new build home). Never had any issue other than the pipework in the airing cupboard where the HW cylinder/pump is located being noisy when the pump runs, this is probably due to the pump being set at a high speed but I never bothered to drop it down. So a few days ago I noticed that the radiator in the bathroom was cold, I checked that the TRV pin wasn't stuck, which it wasn't then bled the radiator and got a lot of air out of it, the system pressure actually dropped to zero, I then topped it up to about 1.25 bar. Since then I get a loud bang every so often in the airing cupboard, it's an initial bang followed by a sort of bouncing noise.
I've been doing some investigation work and have narrowed it down to when it occurs. When boiler receives a no heat required signal it shuts off, all 2 ports close and the pump carries on running for a few minutes (overrun as you'd expect). When the pump finished the overrun and shuts off I get the bang, the pressure remains constant throughout and the bang seems to come from around the expansion vessel, the pressure gauge on the vessel bounces then drops about 0.2 bar, then slowly climbs back to the previous operating pressure.
Anyone had any experience of this before, is it a faulty vessel, pump issues? I have never come across this before.
Thanks Andy
