Hi wonder if I could tap into some collective wisdom/experiences.
We have a panasonic multi-split heat pump system. With 3 high-wall head units.
It is coming up 4 years old.
Last summer one of the high wall units developed an intermittent rough electrical/humming sound. This sound would usual last about 30 seconds then stop. It would sometimes happen every 5 minutes, then sometimes not at all.
It does not seem to be related to the fan, and it is quiet a bit louder than the normal fan sound when on quiet.
The difference between this unit and the others is that it has a condensate pump.
The sound does not occur when the unit is used for heating, so we have not had it for the past 8 months.
But turned the unit onto cooling a similar thing happened. Although this time the sound continued after the unit was switched off. In fact started up about 15 minutes later. I had to turn the isolation switch off.
The unit is in my daughter bedroom and used at night. So it needs to be quiet.
We had a person have a look at it yesterday, but they did not seem that experienced and did not know what the problem was, and of course it wasn't making the noise.
I wonder if this sounds familiar to anyone else?
I suspect it is something to do with the condensate pump, but not sure how to test that or if they can be isolated.
Cheers for any help.