S
Stephen Luxton
I have an oil fired system boiler driving a hot water cylinder and radiators through a Honeywell three port mid position valve. Before that we had a Worcester boiler, through a Danfoss mid position valve.
Problem is loud humming/vibration through the pipes around the cylinder, loud enough that it can be heard all over the house.
When the Worcester was fitted about two years ago (whole system from new including stainless HW cylinder and all new radiators), it was fine to start with, and then after a few months it started vibrating badly. After talking to plumbers and research on the internet I decided it was the valve, disabled it and left it in a manual position that didn't vibrate through the winter.
Six months ago the Worcester boiler proved to be a bit of a disaster for unrelated reasons so I had it changed for the current Firebird boiler and at the same time changed the Danfoss valve for a Honeywell. Problem solved, or so I thought. Wrong.
I am not a plumber but do have a reasonable amount of common sense and fault finding ability. Through a process of elimination I have found that
- It doesn't vibrate at any pump speed on CH only
- It usually vibrates at any pump speed on HW only, but worse as the pump speed increases
- It vibrates at higher pump speeds (2 & 3) on both CH + HW
- Vibration is worse when the system water pressure is higher
I have experimented with water pressure and it's best when the water pressure is so low that the boiler sensor only just comes on. Charge it to the proper water pressure of 0.5bar cold and it's a lot worse especially when it heats up to ~ 1.5bar.
At the minimum pressure, which doesn't show on the gauge, the hot pressure is ~ 1 bar, and it is silent on all settings when the pump is circulating and it's all completely cold.
Given that the only common part of the hot water system is the cylinder and pipes (and the pipes are fine in CH mode), I'm wondering if the coil in the HW cylinder is the culprit? It is definitely coming from the area of the valve / cylinder as that is in one cupboard and the system boiler (containing the pump) is in another - there is transmitted noise there but much quieter.
The HW cylinder was about £800 so I don't really want to change it on the off chance but has anybody come across this problem being caused by a coil? I suspect the vibration will eventually break the coil anyway, as it is a terrible noise when it really gets going and you can hear it all over the house.
My other thought is to convert it away from a sealed system, put in a header tank and disable the pressure sensor, which will minimise the hot pressure and get rid of the noise, but I shouldn't have to do this! Is the HW cylinder a possible culprit?
Thanks.
Problem is loud humming/vibration through the pipes around the cylinder, loud enough that it can be heard all over the house.
When the Worcester was fitted about two years ago (whole system from new including stainless HW cylinder and all new radiators), it was fine to start with, and then after a few months it started vibrating badly. After talking to plumbers and research on the internet I decided it was the valve, disabled it and left it in a manual position that didn't vibrate through the winter.
Six months ago the Worcester boiler proved to be a bit of a disaster for unrelated reasons so I had it changed for the current Firebird boiler and at the same time changed the Danfoss valve for a Honeywell. Problem solved, or so I thought. Wrong.
I am not a plumber but do have a reasonable amount of common sense and fault finding ability. Through a process of elimination I have found that
- It doesn't vibrate at any pump speed on CH only
- It usually vibrates at any pump speed on HW only, but worse as the pump speed increases
- It vibrates at higher pump speeds (2 & 3) on both CH + HW
- Vibration is worse when the system water pressure is higher
I have experimented with water pressure and it's best when the water pressure is so low that the boiler sensor only just comes on. Charge it to the proper water pressure of 0.5bar cold and it's a lot worse especially when it heats up to ~ 1.5bar.
At the minimum pressure, which doesn't show on the gauge, the hot pressure is ~ 1 bar, and it is silent on all settings when the pump is circulating and it's all completely cold.
Given that the only common part of the hot water system is the cylinder and pipes (and the pipes are fine in CH mode), I'm wondering if the coil in the HW cylinder is the culprit? It is definitely coming from the area of the valve / cylinder as that is in one cupboard and the system boiler (containing the pump) is in another - there is transmitted noise there but much quieter.
The HW cylinder was about £800 so I don't really want to change it on the off chance but has anybody come across this problem being caused by a coil? I suspect the vibration will eventually break the coil anyway, as it is a terrible noise when it really gets going and you can hear it all over the house.
My other thought is to convert it away from a sealed system, put in a header tank and disable the pressure sensor, which will minimise the hot pressure and get rid of the noise, but I shouldn't have to do this! Is the HW cylinder a possible culprit?
Thanks.
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