Vibration from Neighbor's Mini-Split

[windyplayer]

My neighbor got a Daikin mini split heat pump - looks like a two zone since there are two conduits running along the outside of the house. One Fan.

I notice vibrations in my house which is 50-75 feet from their house.

I would have expected that the unit would be isolated from the pad that the outside unit was mounted to. Is this not the standard installation technique?

No support phone numbers at Daikin and no install in my immediate area. I want to do research and know what I'm talking about before I approach my neighbor.

I can feel the vibrations in the floor of my house and know whenever their unit is on.
Thanks a bunch.
wp

 

[Dana]

Most mini-split mount kits shipped with the unit have thin rubberized grommets/washers, with minimal isolation, but some, and are often omitted when mounted to a free-floating condenser pad resting on dirt/gravel. But it's also pretty common to install thicker vibe-damping mounts/feet on mini-split compressors, which are particularly for use when bracket-mounted to the walls or on flat roofs. (A web search on the terms vibration+mount+mini+split+price and turns up dozens of products.)

It's a bit unusual for the low-frequency vibration to make it through 50-75' of dirt to the structure of the house at a level that you could feel. It must be dead obvious (really annoying) inside the house it's serving!

Is the unit just bolted onto concrete blocks on a condenser pad, or on adjustable mounts?

^^This isn't very isolated at all, screwed directly to the concrete blocks

^^plastic riser transmit less vibration than concrete or steel, but can be improved with rubber pads where it's bolted on.

^^simple rubber feet help, but may not be enough at ultra low frequencies that would be felt 50' away on dirt.

^^ Coil spring type isolators are more expensive, more commonly used on roofs, but could be what's called for here. You'll need to know the weight of the unit to be able to specify it. (You can look up the weight if you know the model number.)

 

[Sponsor]

 

[WorthFlorida]

My neighbor got a Daikin mini split heat pump....I can feel the vibrations in the floor of my house and know whenever their unit is on.

That is an incredible amount of vibration and it is not normal. Did this unit always have this vibration and how old do you think it is. ? Have you talked to your neighbor? Ask, as you suspect, if both units are working.

When the fan inside an air handler stops running while the compressor is running, liquid refrigerant works back to the compressor. Lack of air over the evaporator coils does allow all of the refrigerant to turn into a gas because the coils are icing up. Compressors are not designed to pump liquid and causes very high head pressure. The motor inside the compressor really works hard and you'll hear a vibration from the compressor. If there are two cassettes in the home, one may not be working. Two months ago my neighbor informed me that my AC compressor was making a loud noise that was not normal. It sits right next to his patio. Sure enough the air handler fan was running intermittently.

Another possibility is the outside condenser fan is not running to allow the hot refrigerant gas to condense to a liquid. This will also cause strain on the compressor and it will vibrate.

 

[Jorgebaloy]

Hanging the outdoor unit on stud walls can be problematic, as you can get resonance between the unit and the structure. (The installation manual specifies a "rigid wall structure" for that reason.) On wall hung installations on stud walls I use rubber isolation pads between the feet of the unit and the bracket or floor pad (floor) to reduce this and I've not had any complaints.

 

[windyplayer]

The unit is bolted directly to concrete blocks sitting on the ground. However I was wrong about this unit causing the vibration. My neighbors are on vacation, so I can't talk to them directly, yet. But I walked around the house and found that the Mini-split was off but the hot tub pump was running and the vibration was particularly bad on the concrete patio where the hot tub is sitting. So apparently the problem is the Hot-Tub pump. I'll talk to my neighbors about their hot-tub when they get back.

Thanks for your insights.
False alarm on the mini-split vibration.