vibration / resonating

[derekj]

Hi, I'm new to this and need some help with what will seem like very basic questions to you guys in regard to plit wall mounted inverter heat pumps.

The outdoor unit seems relatively quiet but the noise from it is muchy louder inside. Noise seems to be not only transferring through the pipework to the indoor unit but also the house framing seems to be carrying it.

Everything seems well insulated and fixed etc.

The noise is okay until the compressor is at it highest load/speed.

What are the possible causes and solutions and what should I be looking for?

Hope you will help as I am unable to get much help from my associates. (Its a long story )

Thanks...Derek

[Paulajayne]

Hi
"Everything seems well insulated and fixed etc."

Try loosening all fixing points and recheck - If the noise level goes down then tighten each in turn and check at each stage - this may help you to identify the problem.

Are the pipes resting on anything?

Do a search for vibration nulling mountings / screws/ bolts.
Things like this :- http://www.antivibrationmethodsrubbe...html/foot.html

HTH

Paula

[derekj]

Thanks Paula,
I appreciate you can be bothered to help with things so basic. I will try that. Is noise transfer in liquids different between different refrigerants operating at different pressures? These I am talking about are using R 410.
Also these units are pre gassed for 5 metres...How much difference does each metre longer or shorter of pipe run make?

Regards ...Derek

[Brian_UK]

The pipe length shouldn't really make a difference, as Paula suggested try each fixing point in turn.

It could be that when the compressor is fully loaded, max speed, then a harmonic is being set up somewhere and being transmitted along the pipework into the structure. With the cover off, beware electrics !!!, and the unit running try pressing each bit of pipe with something like a screwdriver (hot pipes will burn your fingers ) to see if the vibration stops.