- Joined
- 7 Dec 2010
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This is driving me nuts!
Air in sealed system.
Configuration:
New complete system installed 12 months ago.
Upper maisonette, concrete floors, Baxi Duo tech in the kitchen with the flow and return
up into the loft. 6 rads are fed from down pipes from the loft into the rooms with 1 rad
a floor lower on the ground floor hall.
After the initial installation I was unhappy with the heat output in the hall. As I had a
spare small rad I installed it in the upper hall. I would have asked the original installers to
resolve the problem but having made my own modifications I felt that to be inappropriate.
Problem experienced:
Air bubbles moving around the system making annoying noises for the initial half hour when
on. The noise stops when the rads get warm and the problem goes away until the system cools
and starts the next time from cold.
Action taken:
No amount of rad bleeding when cold shows any sign of air, however air would often show if the pressure was
isolated within the rad by closing the rad valves, air would show just at the last point of bleeding when the pressure
reached atmospheric during bleeding. I have done this many times to the point where no further air was expelled.
I have also installed an auto air vent at the highest point in the loft but still continue to have air problems.
I have tried running the system one rad at a time and I have also tried running the system with minimal pressure.
The noise does go away if the rads are fully open (not balanced) but this is not satisfactory. The best balance I can
get is about 12 degree across all rads but the pump speed makes the system produce more noise than expected. It is my
understanding that the Duo tech does not have adjustable pump speed.
The way I see this is as follows.
Cold system equals lower pressure and larger bubbles until the system warms up and dissipates the bubbles into smaller less noisy
ones.
The question is, why do the bubbles remain in the system, why do they not come out of the auto air vents or rise to the
top of the rads when cold to allow bleeding. How can I remove the air?
Air in sealed system.
Configuration:
New complete system installed 12 months ago.
Upper maisonette, concrete floors, Baxi Duo tech in the kitchen with the flow and return
up into the loft. 6 rads are fed from down pipes from the loft into the rooms with 1 rad
a floor lower on the ground floor hall.
After the initial installation I was unhappy with the heat output in the hall. As I had a
spare small rad I installed it in the upper hall. I would have asked the original installers to
resolve the problem but having made my own modifications I felt that to be inappropriate.
Problem experienced:
Air bubbles moving around the system making annoying noises for the initial half hour when
on. The noise stops when the rads get warm and the problem goes away until the system cools
and starts the next time from cold.
Action taken:
No amount of rad bleeding when cold shows any sign of air, however air would often show if the pressure was
isolated within the rad by closing the rad valves, air would show just at the last point of bleeding when the pressure
reached atmospheric during bleeding. I have done this many times to the point where no further air was expelled.
I have also installed an auto air vent at the highest point in the loft but still continue to have air problems.
I have tried running the system one rad at a time and I have also tried running the system with minimal pressure.
The noise does go away if the rads are fully open (not balanced) but this is not satisfactory. The best balance I can
get is about 12 degree across all rads but the pump speed makes the system produce more noise than expected. It is my
understanding that the Duo tech does not have adjustable pump speed.
The way I see this is as follows.
Cold system equals lower pressure and larger bubbles until the system warms up and dissipates the bubbles into smaller less noisy
ones.
The question is, why do the bubbles remain in the system, why do they not come out of the auto air vents or rise to the
top of the rads when cold to allow bleeding. How can I remove the air?
