View Full Version : Heat & A/C How often does your A/C compressor cycle on and off when you have the A/C on?
rothsean
08-01-2013, 09:18 PM
Mine seems to cycle off every 30-60 seconds for a few seconds, then back on again. Is that normal? (compressor is 1 year old from DMCH) My Freon pressures today where 35psi/180psi (low/high), within spec.
On another note, my nephew has a 2005 Ford Focus. His A/C is only blowing warm air so yesterday I hooked up my gauges and the readings were very strange. The low side was at 120+psi (pegged on the top of the scale) and the high side was around 160psi.
What would make the low side be so high?
DMCMW Dave
08-01-2013, 09:28 PM
Mine seems to cycle off every 30-60 seconds for a few seconds, then back on again. Is that normal? (compressor is 1 year old from DMCH) My Freon pressures today where 35psi/180psi (low/high), within spec.
On another note, my nephew has a 2005 Ford Focus. His A/C is only blowing warm air so yesterday I hooked up my gauges and the readings were very strange. The low side was at 120+psi (pegged on the top of the scale) and the high side was around 160psi.
What would make the low side be so high?
Overcharged, but that doesn't spontaneously happen. Are you sure you opened the connection valves on the gauges (i.e so they really opened the schraders)?
DMC5180
08-01-2013, 09:28 PM
Check too see if the radiator fan(s) are coming on when the compressor engages.
DMC5180
08-01-2013, 09:41 PM
Overcharged, but that doesn't spontaneously happen. Are you sure you opened the connection valves on the gauges (i.e so they really opened the schraders)?
the 2005 focus (134a) quick connect gauge set. I think the type you are referring too is for R12
rothsean
08-01-2013, 09:44 PM
the 2005 focus (134a) quick connect gauge set. I think the type you are referring too is for R12
I have a 134a manifold pressure set with r12 adapters too, so it works on both systems.
I did have the valves open completely and was getting accurate pressure. I thought it was very high so I released the low side down to about 40psi. The high side went down to 60psi or so when I did that.
rothsean
08-01-2013, 09:45 PM
Check too see if the radiator fan(s) are coming on when the compressor engages.
On the D? Yes it does, at least at idle the fan comes on for sure.
David T
08-01-2013, 09:53 PM
Mine seems to cycle off every 30-60 seconds for a few seconds, then back on again. Is that normal? (compressor is 1 year old from DMCH) My Freon pressures today where 35psi/180psi (low/high), within spec.
On another note, my nephew has a 2005 Ford Focus. His A/C is only blowing warm air so yesterday I hooked up my gauges and the readings were very strange. The low side was at 120+psi (pegged on the top of the scale) and the high side was around 160psi.
What would make the low side be so high?
It is all dependent on the ambient temperature, the low pressure switch setting, and the motor speed. At around 80 degrees F and 775 RPM it should not be cycling. At 1200 RPM it should cycle on about 10 seconds and off about 15 (this can vary a LOT). This is with R-12 and the Mode switch on NORM and the fan on 3 or 4.
As for your Focus, it sounds like you have air in the system.
David Teitelbaum
rothsean
08-01-2013, 10:02 PM
It is all dependent on the ambient temperature, the low pressure switch setting, and the motor speed. At around 80 degrees F and 775 RPM it should not be cycling. At 1200 RPM it should cycle on about 10 seconds and off about 15 (this can vary a LOT). This is with R-12 and the Mode switch on NORM and the fan on 3 or 4.
As for your Focus, it sounds like you have air in the system.
David Teitelbaum
Sounds good about the D, that is basically what mine does.
So, the Focus. Is there a way to troubleshoot if the compressor or orifice are bad? I don't want to replace them if I don't have to.
DMC5180
08-01-2013, 10:07 PM
I have a 134a manifold pressure set with r12 adapters too, so it works on both systems.
I did have the valves open completely and was getting accurate pressure. I thought it was very high so I released the low side down to about 40psi. The high side went down to 60psi or so when I did that.
Yeah you just emptied your system. are you checking the system pressures with t the A/C running?
DMC5180
08-01-2013, 10:08 PM
On the D? Yes it does, at least at idle the fan comes on for sure.
No. On the Focus
rothsean
08-01-2013, 10:10 PM
Yeah you just emptied your system. are you checking the system pressures with t the A/C running?
Yes, A/C running and fan on max.
I did not completely empty it. I dropped the pressure down to 40ish on the low side and high side went to 60ish....
I tried to then add some 134a Freon and the pressure immediately rose to 80psi and stabilized at 65psi, that was with just a quick shot of Freon for about 2 seconds total.
rothsean
08-01-2013, 10:12 PM
No. On the Focus
Not sure. I did not hear it but I did not check for that either. Do you think that I should try to run the A/C when the car is completely cold and see if it gets cold for a few seconds then stops?
What are you thinking with the fan issue?
DMC5180
08-01-2013, 10:33 PM
Not sure. I did not hear it but I did not check for that either. Do you think that I should try to run the A/C when the car is completely cold and see if it gets cold for a few seconds then stops?
What are you thinking with the fan issue?
Yes try that.
What I'm I thinking is what I experienced on my wifes Cadillac last week. It was a really hot day. She was down town running errands and while parked she sees the engine temp climb to some excessive numbers and then the A/C started blowing hot air. I get the panic phone call at work. OMG the sky is falling. She lets the car sit for a while and cool down. Then starts it up and drives home engine temps appear to be normal While moving. When I finally had a chance to look things over, I discovered the Fans were not running with the A/C compressor. I traced it to a blown 50A maxi fuse. I replaced the fuse and the fans started running again. well one of them ran normally and the other ran very slow. Turned Out the Slow fan was Bad, that's what caused the fuse to blow. If you don't have fans pulling air over the condenser the High pressure HOT gas does not condense to liquid and goes to the evaporator instead of liquid refrigerant. End result blowing hot air. As soon as the fans were working again all was nice and cool again.
$ .02
So, far everyone seems to think it has the symptoms matching low side HIGH and high side HIGH, but 120/160 sounds like HIGH/OK to me (for ~80F ambient). Or are the Focus pressures WAY different??
Compressor or damaged Orifice/Control Valve.
DMCMW Dave
08-01-2013, 11:07 PM
the 2005 focus (134a) quick connect gauge set. I think the type you are referring too is for R12
No, on the quick connects the hoses are sealed until you snap them on and open the valves on the connects, which also pushes the schraders open. The valves on the gauge set part remain closed unless you want to let the Freon out.
Bitsyncmaster
08-02-2013, 06:10 AM
The 120 PSI low side and 160 PSI high side says the compressor is shot (like Ron suggested).
DMC5180
08-04-2013, 12:55 AM
No, on the quick connects the hoses are sealed until you snap them on and open the valves on the connects, which also pushes the schraders open. The valves on the gauge set part remain closed unless you want to let the Freon out.
Agreed, My cheap set has inline valves in the hoses. Where as some of the better sets have valves on the quick connection. I forgot I had those inline valves on my set which obviously I have to have open to get correct gauge readings.
Agreed, My cheap set has inline valves in the hoses. Where as some of the better sets have valves on the quick connection. I forgot I had those inline valves on my set which obviously I have to have open to get correct gauge readings.
I don't know... I've never seen a valve on a can tap quick connect, or top off, even if it had a gauge. "Quick connects" do just that, and can surprise one if there is a leak downstream...
A lot of gauge sets don't have valves in their hoses either. That is "cheap" -- Dave just has the fancy schmancy set. :devil:
Nice to have after some bozo used Locktight on a R12/134a port adapter but didn't run it down enough. :rant:
Bitsyncmaster
08-04-2013, 09:14 AM
My gauge set for R-134a will hold the pressure when I remove it. So I guess it has shut offs at the quick connect. Not sure if my R12 gaughe set will do that.
Same here for one 134a set (w/R12 is wide open.)
DMC5180
08-04-2013, 11:36 AM
Fancy Schmancy quick connects with built in valves (colored knobs) these are on our service machine at work.
20954
My cheap set with Inline valves. On this Set the blue dial LOW Side gauge rotates (is a valve). CLOSED is for reading LOW side gauge and OPEN is for Charging.
20955
and then the more traditional style has the valves up on the sides of the manifold.
20956
Ah, I see the snag now...
My station connections are R12 w/ classic Yellow Jacket gauge set. (For 134a, I have to change a converted split tan, and use a manifold set similar to the last pic, with hose quick connects, for toys; short port quick disconnects as in the 2nd pic, odd angles, other toys etc. (eg. pop a gauge on the low side, first, evacuate, and walk away with the rest during a leak down test (aka, while your $hit is locked up at night ;-)
My first thought when buying them was, "Oh boy lots of places to leak", but I use them a lot and never had a problem with them.
I like toys.
Sean is MIA...
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