Hi all,
I have a Baxi back boiler with hot water cylinder in bedroom and F&E tank in attic. Quite a small system, 4 rads and 1 towel rad.
The heating and hot water system are performing fine, no issues with cold spots and hot water is good.
The issue is a very noisy system. I am regularly able to bleed out a small amount of air from the upstairs rads and/or vertical pipes next to cylinder and pump.
I have observing behaviour of the system and am fairly sure the whooshing noises only occur when the hot water is switched on. Heating only, no noises.
If the hot water is switched on with the heating the sound of air circulating around the upstairs radiators follows this whooshing.
With the system cold I held a pint of water over the expansion pipe up in the attic and had someone switch the hot water on, almost a whole pint was sucked up pretty much straight away. I refilled the glass and held it under the expansion pipe for a further 10 mins but only air was expelled, no more sucking.
Is this normal behaviour? Should the expansion ever suck? I'm thinking not and it's drawing in air causing all of the noises.
I have opened the rad bleed valves with the system running whilst I can hear this air flowing through the rad, particularly noisy at the TRV, but no air comes out of the rad bleed. Why is this? Does the flow of water carry it straight out of the rad?
Thanks a lot for any help and advice.#
EDIT - I should add that the F&E tank doesn't look very dirty, a very thing layer of orange/brown in the bottom. Thickness of paper.
I have a Baxi back boiler with hot water cylinder in bedroom and F&E tank in attic. Quite a small system, 4 rads and 1 towel rad.
The heating and hot water system are performing fine, no issues with cold spots and hot water is good.
The issue is a very noisy system. I am regularly able to bleed out a small amount of air from the upstairs rads and/or vertical pipes next to cylinder and pump.
I have observing behaviour of the system and am fairly sure the whooshing noises only occur when the hot water is switched on. Heating only, no noises.
If the hot water is switched on with the heating the sound of air circulating around the upstairs radiators follows this whooshing.
With the system cold I held a pint of water over the expansion pipe up in the attic and had someone switch the hot water on, almost a whole pint was sucked up pretty much straight away. I refilled the glass and held it under the expansion pipe for a further 10 mins but only air was expelled, no more sucking.
Is this normal behaviour? Should the expansion ever suck? I'm thinking not and it's drawing in air causing all of the noises.
I have opened the rad bleed valves with the system running whilst I can hear this air flowing through the rad, particularly noisy at the TRV, but no air comes out of the rad bleed. Why is this? Does the flow of water carry it straight out of the rad?
Thanks a lot for any help and advice.#
EDIT - I should add that the F&E tank doesn't look very dirty, a very thing layer of orange/brown in the bottom. Thickness of paper.