Reducing heat pump vibrations through flat roof

Air Source Heat Pumps (ASHPs)

Last Post by sten_super 9 months ago

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sten_super

(@sten_super)

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Joined: 9 months ago

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Topic starter 10/12/2024 6:02 pm

In the most recent YouTube video 'Heat Pump Noise Nightmares?', near the start Patrick Wheeler from VitoEnergy talks about flat rooves 'drumming' due to heat pumps - I have an issue along these lines. The heat pump is wall mounted above the flat roof, and the pipes from the heat pump pass through the flat roof to the hot water tank and other pipes in the garage below. Whenever the heat pump works hard, the outbound pipe from the external unit vibrates, and this vibration carries through to the point where the pipe goes through the roof, and causes (I think) the roof to vibrate. This vibration then passes into the brick external house wall at the side of the house, and then through the property.

The end result is that while there's no noise outside, in the house when the hot water is being heated, or the heat pump is running hard (including defrost mode), there's a droning noise. It's most obvious in the bedroom the other side of the wall from the heat pump, but you can hear it also in any room that shares that wall (either ground or first floor), as well as across the front of the house. It's no problem in the daytime, but at night-time it's loud enough to hear clearly from three of the bedrooms, and it causes disturbance for everyone who uses the guest bedroom (which is the one adjacent to the heat pump).

There is some flexible piping coming off the heat pump before switching to fixed pipes, but not enough to dampen the vibrations completely. It's definitely the pipe that's vibrating, and not the bracket for the heat pump. The installer has come out once to try to fix it with no luck - I'm planning to ask him to look again when the annual service is due in February. Does anyone have any suggestions for how to address this issue?

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newhouse87

(@newhouse87)

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11/12/2024 12:03 am

Have wall mounted unit myself which i can hear all around the house when running hard. Herself mentioned it this morning when i came home from work, she didn't know what it was as normally deep sleeper and has zero interest in heat pumps surprisingly. I always hear it however.

My solution early next year is to build up small ledge to unit and unscrew wall bracket from wall and get anti vibration feet for unit and fix it all to my small concrete ledge.

This post was modified 9 months ago by Mars

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PatrickVito

(@patrickvito)

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11/12/2024 12:18 am

Hi Sten,

It sounds like there is insufficient clipping and/or insulation on the primary pipework. If it properly secured and lagged to avoid pipes touching and knocking then the only sound inside should be water moving through the system. Although this can be audible, the sound you describe exhibits as a mechanical installation issue.

I hope that helps, your installer should be rectifying as part of their workmanship guarantee.

Patrick

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sten_super

(@sten_super)

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Topic starter 11/12/2024 11:45 am

@patrickvito Hi Patrick, thanks so much for taking the time to reply and for your advice. When my installer came back originally (in May) he added another clip, but I'll push him to come back again and take another look. I think that's got to be the required measure, the pipes are definitely thoroughly and comprehensively insulated!

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