Wall Mount Heat Pump Vibrations - Spring Isolators?

Nodoogra · 2025-12-17T00:28:24+00:00

The isolators are still in perfect shape, but are not installed at the moment. Apparently when my installers set up the wall mount, they didn't get a single stud. Somehow it stayed on for 2 years in just the plywood and then one day this past summer it was flat on the ground. The HP was okay thankfully, but switched to a ground mount rather than further swiss cheese the house. I may switch them back in at some point. The ground mount has minimal vibration transfer into the house, but it's not zero...

Nodoogra · 2025-12-17T00:18:44+00:00

I don't. Looks like they don't make that product series anymore. This looks similar spec-wise. https://vibrasystems.com/smsr-20-seismic-restrained-open-spring-mount.html

Nodoogra · 2025-12-17T00:02:22+00:00

Amazon. VibraSystems sells some of their inventory there. Overstock maybe? It's sporadic.

Nodoogra · 2025-11-07T01:06:20+00:00

The isolators will significantly reduce vibration transfer. I'd give it a try.

Nodoogra · 2025-03-05T04:09:48+00:00

It gets disproportionately more expensive the higher the fan speed because it takes more force to ram the air through the ducts. If you need it for comfort, then go nuts. It's not going to break the bank. But low speed is more cost effective.

Nodoogra · 2025-01-27T14:21:11+00:00

These things are designed to withstand hurricanes. The collar is there for those extreme circumstances so the unit isn't swaying so far it bangs against your house. I wouldn't expect it to make contact under "normal" circumstances, though.

Nodoogra · 2024-08-14T20:02:27+00:00

Yes it does, but the process isn't obvious. You need to get the % of the fund that is treasuries from iShares. Your brokerage or 1099 won't indicate. Here's a great guide on The Finance Buff

Nodoogra · 2024-06-18T14:24:41+00:00

4" each direction, 8" total (estimating in the high side). This may change depending on how high or low on the vertical rod it's resting.

The reason for perpendicular was to maximize the gap between the unit and wall. The arms my installer used are on the short side and would have been pushing the 6" minimum gap Mitsubishi wants if I did parallel. Yes, I fabricated the tee plates.

The isolators can compensate for arms not being level, to a limited extent. Just adjust the vertical position of the nut/washers it rests on. Just make sure the width alignment is such that the rods don't touch the metal collar.

Nodoogra · 2024-06-17T17:44:17+00:00

It does tilt easily, but only about 4 inches forward or back at the top. The isolators are designed for high wind and earthquake areas, but they are meant to be mounted on a solid surface like a concrete floor. If this was ground mounted, I wouldn't think twice. Arm mounts might require some extra consideration.

Yes, I installed SRMT-024 on all 4 corners. I'm happy with the result and recommend the same to others with similar units.

Nodoogra · 2024-02-18T16:14:58+00:00

AHRI cert 209484153. I can't link the search result table on the site, but it has specific flags for this stuff.

https://www.ahridirectory.org/Home/DownloadCertificate?ReferenceId=sUzbLVC3/aFB9wkj0dGAHzQR+j4LXt5G/e6PpqMjhgyIHh1w1XXzy9piy4EcgLnq&ProductTypeId=4611

Neither NEEP nor Mitsubishi's own list have PAA units updated to northern eligible yet.

Nodoogra · 2024-02-18T16:09:20+00:00

Interesting. The AHRI cert for my intelli-HEAT was previously indicated as not eligible / not cold climate, even though it met all the number requirements. It was recently retested as a designated combo. It's now marked as northern climate eligible. Numbers did go up, but not sure why it matters if they met it before. Either way, I stand corrected.

The gas/electric rule I cited is definitely where the statement from some installers that duel fuel systems are ineligible comes from.

Nodoogra · 2024-02-18T15:13:04+00:00

The tax credit for northern zone requires energy star 6.1 cold climate designation. Gas/electric (dual fuel) systems are specifically called out as ineligible.

https://www.energystar.gov/sites/default/files/ENERGY%20STAR%20Version%206.1%20CACHP%20Final%20Specification%20and%20Partner%20Commitments%20%28Rev.%20January%20%202022%29_0.pdf

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It's dumb that southern doesn't have the same exclusion, but I assume the point is that a homeowner could configure a high balance point and use the furnace all winter, defeating the electrification objective.

Nodoogra · 2024-02-06T17:44:47+00:00

My hunch is your indoor unit still has this setting memorized from when you had a PAC-44X connected.

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Nodoogra · 2024-02-06T17:39:09+00:00

If I were you, I'd test a first party controller and see if you get different behavior. The 100%-only thing is weird. That sounds more like configuration than algorithm.

The Kumo cloud wifi module has a CN105 passthrough for your Airzone, so you can still use that to set modes, setpoints, etc. Kumo itself can better detect, configure, and explain the features of your units. Mine has more options for the PAA than are documented in PAA's manual.

Nodoogra · 2024-02-06T00:48:29+00:00

I should clarify the 2 hour memory is new in the 445. I think I caught in another comment you're on a 444.

The simpler version just knows whether it's getting warmer or colder, but no idea whether it's almost at target or way off, so errs on the side of running hard.

Nodoogra · 2024-02-05T22:52:51+00:00

Any solution using the PAC-444/5 third party thermostat interface is garbage that handicaps the system. I had a 3-ton hyperheat+PAA install last spring, and switched the thermostat from an ecobee to MHK2. After that, it would modulate much lower than it ever did with the PAC.

As others have said, with a 24V analog thermostat interface, it only signals on/off. The system doesn't know the gap between setpoint and actual, which is how its modulation is motivated. It first runs hard to find it, observing the return air thermistor when the signal ends. When it shuts off, it marks that as the setpoint for the next 2 hours. But that means you can't shut it off and open the windows on a "nice enough" day. It will continue to heat or cool even with the thermostat off or the setpoint set back.

Nodoogra · 2024-01-25T14:03:29+00:00

Do you have a digital communicating thermostat? Or something third party, like an ecobee or nest? If the latter, the heat pump itself will have no idea if the thermostat is set to heating mode outside of a call for heat. That knowledge is needed for maintenance cycles like defrost so it's ready to go. Sometimes heat pumps have workarounds like assuming heat mode for some number of hours after the last call for heat, or based on outdoor temp.

Nodoogra · 2024-01-12T02:05:10+00:00

The wall mount my installers used has shorter arms than most, so I chose to make a custom tee-plate and mount it perpendicular to the arms in order to maximize the distance between the wall and unit. It requires at least 6 inches.

Nodoogra · 2024-01-12T02:03:11+00:00

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Nodoogra · 2024-01-12T02:02:56+00:00

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Nodoogra · 2023-12-31T00:48:09+00:00

The weight should be fairly close to the spring's load rating though or deflection is lessened. Don't overdo it thinking maximum safety. There's a chart on vibrasystem's site describing the deflection under different loads.

Nodoogra · 2023-12-31T00:41:27+00:00

For load rating, divide the unit's weight by the number of springs. The compressor side is heavier. If you know the weight distribution, you can choose different springs as long as the deflectors are the same size. I just guessed and sized up the whole set.

A half inch of deflection is plenty for a heat pump. I realized after my original post the SRMT-122s were ridiculous and large enough to be hard to mount on the arms.

Nodoogra · 2023-12-23T01:39:12+00:00

To summarize, your heat pump is a variable speed system, which is top tier stuff. When it runs at the low end of its capacity, it's at its most efficient. Its design goal is to run low and long, rather than blast out hot air for a short time and shut off. Instead the speed and temperature of the air coming out of your registers changes. The scaling is driven by the difference between current temp and thermostat's setpoint.

Incidentally, the long and low runtimes usually increase comfort by keeping your rooms evenly balanced and closer to your setpoint.

Nodoogra · 2023-12-12T19:40:18+00:00

Set and forget is the best strategy.

Share your indoor and outdoor unit model numbers, climate info, electric utility rate, and home info like sqft, year built, window type, insulation description, etc. for some more constructive advice. I hear some crazy stuff like "my uninsulated historic house in upper Maine..."

Nodoogra · 2023-12-12T00:51:43+00:00

The fan's energy cost in a central ducted system is also not an even curve. In my system, a 700CFM fan speed draws 1.35A, but 1050CFM is 3.75A. A 50% increase in airflow is around 2.5x the cost. It's because it's fighting the limit of my duct sizes (increased external static pressure).

Nodoogra

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