air con pressure switch

[sean sherry]

I rebuilt the compressor now very efficient but the tight belt squeals when hot after running for a while. The compressor seems to load up. Is there a test for the pressure switch ? Should the switch turn off the clutch as necessary ? Thanks Sean

 

[abl567]

Possibly the system is overcharged, resulting in the compressed liquid not fully expanding through the tx valve into the evaporator coil aowing liquid to flood back to the compressor, loading up the compressor. Most automotive systems have a low pressure cut out to prevent the compressor running without gas and therefore coolant and lubricant. they generally dont have a high head pressure control

 

[sean sherry]

Thanks I had some of the gas let out, too much, had to put half back in. Is there not a switch which turns off the compressor when gas expands with heat and builds up too much pressure ? I'm not realy sure how it all works. Sean

 

[Tony66_au]

As ABL said it sounds like your system is overcharged, you may also have the wrong belt as there are many factors involved including the angle of the V if it is a V belt and adjustable tensioners etc

Aircon gas is measured by weight BTW when in its liquid form and it isnt really something that can be guessed.

 

[Helmet]

What brand compressor do you have and does your Receiver dryer have 2 switches ?

 

[sean sherry]

Yes there are two switches ,one switches on the fan and is working Ok The other next to it is a pressure switch ( ? ) the system was charged by a current machine and to Specs. I take the point about the correct angle of the belt. I'll take it off and see where it is driving. Please confirm if the
" Pressure switch " controls the compressor clutch ,i.e., the compressor cycles on and off as necessary according to temperature and load ? ? ? Ps The compressor is a York
Thanks Sean

 

[sean sherry]

I have found a web site on York Compressors To quote "they are crude twin cylinder units with no internal balance " " Load up when hot and vibrate "
Fits mine to the Tee. Cure replace it with a newer 6 cyl. unit . no vibrations and 3 HP draw instead of 7 I feel that my belt is ok as it drives fine and only struggles when the unit is pretty hot and starting to vibrate.. Sounds like the nature of the beast. Maybe not as severe as on the 350 & 450 V8s with much more low down torque .thanks to all...... Sean

 

[Helmet]

M110 engines have a tendency to crack the idler pulley bracket. This results in the belt never being tight enough. maybe check it?
I've been changing over York compressor to Sanden for a few years now, they work more efficiently, quite smooth and freezing cold.