Vibrations
What is causing the vibration?
Fan Grille
Regarding the fan Grilles, Inverter products with ECM motors have been enhanced with a heavier grille. The spreaders on the grill were increased from 1/4” to 5/16” which added mass to the grilles. For (-)A20 and (-)P20 Models built before W3516 a new grille was made available. Some models were updated in our plant, and some updated in distributor inventory, and some were updated in the field by technicians. This update did not apply to the (-)P17 Models because they are equipped with a PSC motor and different fan blade combination.
There should also be a screw in the control box to the right of the line voltage filter on the (-)P20 and (-)A20 models. This helps with vibrations.
Cabinet Bind
Most importantly, and the first thing that must be checked is making sure the cabinet is sitting firmly on a flat and level pad. Pads that are not flat, or not well supported in one corner or another can put the cabinet in a bind. The units are taller than your run of the mill 14 SEER units. Imagine if the Empire state building had a poor foundation. This bind changes the cabinet frequency.
Likewise make sure if heat pump risers are used, that they are sitting properly in the pockets provided in the composite base pan. Make sure the weight of the unit is equal on all corners. This may not seem crucial to some, but changing parts and not addressing the footing, will certainly yield less than desirable results. IF the side panels bind when removing or putting them back in, the cabinet is likely in a bind.
Fan Blades
Fan blades are balanced prior to installation, if a fan blade has lost a weight, it would most likely be sitting in the base pan or below the unit. If there isn’t one, it likely didn’t lose one. Fan blades can be damaged when removing the fan from the system. This goes without saying, but do not set the motor assembly down on the blades and don’t bend the blades to get it to fit. Ensure the unit is beyond where a roof may drain. If there is a gutter above, make sure it’s cleaned out and not allowing water to pour off the roof into the unit. Make sure no icicles can fall into the fan. Make sure all the screws holding the motor below the cap are snug.
Compressors
A compressor should not cause excessive vibrations normally. Check the composite base pan near the compressor bolts to make sure it has not cracked due to poor handling and that all 4 compressor bolts are snug in the brass inserts. These systems have undergone model and strain testing. We have also identified compressor speeds that can excite the cabinet and have blocked those speeds in the software.
See the Noise Link on the previous page
