I live in the northeast in an upper floor apartment in a concrete tower. My 38QRR heat pump is installed on my terrace adjacent to the living area. The unit is mounted on a vibration-deadening pad and is normally very quiet, and I am very accustomed to the normal wintertime sounds generated by the unit because of its proximity - we hear the defrost cycle every 90 minutes along with the associated noises. But occasionally something else happens:
I need to know if there is what I describe as a severe or extreme weather cycle, that kicks-on if the sensor detects specific temperature/humidity conditions. On five separate occasions over the past two years since its installation I've noticed the heat pump go into high-noise cycles lasting 12,24 or 36 hours straight. I can confirm that each noise cycle coincided with heavy snowfall/blizzard conditions. Each time the noise cycle started mid-afternoon and continued in 12 hour increments (typically 24 hours but most recent was 36 hours), during which time the system was fully responsive to the programmable thermostat and continued to provide heat and go into its routine 90-minute defrost cycles. During these loud 12-36 hour periods, the noise is continuous whenever the heat pump is running: a low pitch sound that emanates through the base platform to the concrete floor. It sounds like a vibration, but not one caused by any apparent physical or mechanical issue with the fan; more like the sound it briefly makes during defrost. Standing next to the unit the sound is moderately audible, but it transmits to the rebar in the concrete floor in a way that causes a persistent louder noise to travel throughout my home and most of my building’s twelfth and eleventh floor apartments (my floor = their ceiling). My first carrier heat pump never made such noises except during defrost.
99% of customers have these installed in a yard or rooftop where noise goes unnoticed. Mine is adjacent to a living area and installed on a pad that was to absorb vibration that nevertheless passes right through to the concrete floor that transmits the sound to a good part of my building (ie. at least 20 apartments may notice the ambient nuisance – and the sound resonates down the stairwells of this all-concrete tower).
There’s little information available online:
1. Is this an extreme weather cycle intentionally designed to kick-in when the unit detects it might be buried in snow or coated in ice?
a. If yes, can this cycle be deleted or duration of it or other functions altered (ie. instead of 12-24 hours it is only 1 hour) – my heat pump is protected from weather by a roof overhang, and we live in NY, not Fargo.
b. If no, why is it happening and what needs to be fixed?
2. How can the noise/vibration be further mitigated/isolated?
Thanks in advance. This is a great forum.