Jim Spence wrote:
I have only seen the "clunk on cycle off problem" twice. Both times it was an all in one unit (compressor, evaporator, condenser and blower in one package.) The first the compressor was mounted less that 1/8 inch from the blower. I loosened the mounting bolts and rotated the unit away from the blower and re-tightened them. The second time I saw it was another unit that had been removed and reinstalled, apparently when they put it back in they bent the mount for the condenser coils, again, almost touching the compressor. I fixed the mount and they had no more problems with the unit. My experience with high head pressure is that a lack of cooling or the unit shutting down from the thermal over load would be noticed first.
*That's Cool Jim *
* Wasn't trying to challange you...But this is all I have done for a living for well over 20 years, and with all respect & fairness to you...I may have seen just a few more systems than most...It is a common issue...
Heck...My refrigerator clunks at home on shut off if it gets too much pet hair sucked up in it's air cooled condenser... *
If you have a piston compressor in your unit...Take your hand (with it not running) and shake it around a bit...Bet you hear the same clunking...(don't worry it won't hurt it)
Rotary compressors of today in self contained units are less prone to make the clunk (because of internal construction) when compared to the piston compressors of Split systems, or older self contained units....
Though they are a dying breed...There are still many Piston type compressors out there in self contained units...And just this year we starting to get away from piston compressors in the 16K and smaller split systems that run the new "Green" 410a refrigerant...
Here's an article I wrote, and later edited, about refrigerants & compressors that can explain more:
-- Edited by spcoolin on Tuesday 14th of June 2011 08:58:01 AM