AC stopped working
08-31-2021, 09:48 AM
#1
Junior Member
Thread Starter
AC stopped working
90 F150 converted to new refrigerant a while back. Had ICE COLD AC until this week.... noticed the AC clutch kicks on and off for 2-3 secs at a time, but no cold air. Connected gauges and I am not seeing any pressure from the Low side...and lots of pressure from the High side. Very strange....
I would assume that means there is a clog somewhere and not getting correct circulation? Any ideas from anyone?
I would assume that means there is a clog somewhere and not getting correct circulation? Any ideas from anyone?
08-31-2021, 04:56 PM
#2
Senior Member
Suggest you're on the right track with suspecting a blockage, now for the hard part of finding 'where'. Don't overlook the possibility of a loss of freon, as your description of lotsa high side pressure may still not be sufficient for normal operation.
The low-pressure side compressor cutout was set to occur when below 28 psi with the R12 system.
Been a few years for me (like about 25), but recalling the recommendations for conversions at the time I did mine - the low pressure cutout was suggested to be reduced to 22psi via the adjustment screw on the bottom of the sensor - have to unscrew it off the dryer to access. Also, it was recommended to install a high-pressure cutout - here's where I'm not sure if this is still a current or applicable thing - to cut the compressor out for high-side pressures over ~350psi. Either a low pressure on the low side or a high pressure on the high side was to disengage the compressor.
At any rate, since your system was working fine - first thought is enough freon has somehow leaked out, mostly because it's easy to check without evacuating the system, resulting in the cycling and lack of cooling. Next up would be the orifice by the dryer has become blocked, likely due to a chunka crud coming loose.
And for the typical line - if you're not familiar with A/C systems and their risks, may be best to get a pro involved.
Good luck, and keep us posted.
The low-pressure side compressor cutout was set to occur when below 28 psi with the R12 system.
Been a few years for me (like about 25), but recalling the recommendations for conversions at the time I did mine - the low pressure cutout was suggested to be reduced to 22psi via the adjustment screw on the bottom of the sensor - have to unscrew it off the dryer to access. Also, it was recommended to install a high-pressure cutout - here's where I'm not sure if this is still a current or applicable thing - to cut the compressor out for high-side pressures over ~350psi. Either a low pressure on the low side or a high pressure on the high side was to disengage the compressor.
At any rate, since your system was working fine - first thought is enough freon has somehow leaked out, mostly because it's easy to check without evacuating the system, resulting in the cycling and lack of cooling. Next up would be the orifice by the dryer has become blocked, likely due to a chunka crud coming loose.
And for the typical line - if you're not familiar with A/C systems and their risks, may be best to get a pro involved.
Good luck, and keep us posted.
09-01-2021, 06:41 AM
#3
Senior Member
My air on my 1991 hasn't worked for over 20 years. I can put a large can of Freon in it and will blow ice cold air for 3 or 4 weeks. I know I have a leak but don't know enough about how to fix it. Been told it will cost near $1,000 to fix it from a pro 
. I'll just live with it. The heater works great 
Let the people who know what they are doing fix it
. I'll just live with it. The heater works great Let the people who know what they are doing fix it
09-01-2021, 04:04 PM
#4
Junior Member
Thread Starter
Shop just called and said it was low on freon... guess I will take their word for it and hope for the best. Thank goodness the season should be changing here soon, I cant live without AC hahahahah