Original message
| samadams
 |  "ac high pressure goes off"
, posted Thu 17 Jun 22:06  
After running for 5 days the high pressure switch turns off the compressor. The compressor cools ok after resetting the high pressure safety switch. Mechanic says that it could be number of problems. I see that coil is clean, wires are tight. My knowledege is very limited. Mechanic has come 3 times and reset the high pressure switch and charged me each time! What are my options. Thank you
ss
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Replies:
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| G&M
| "Re(1):ac high pressure goes off" , posted Wed 22 Sep 18:36
ive had this show up on other units if the filters are clean and the other things that you were told to do are ok, i would have a very good a.c. tech look at the location of the pressure switch it may be where it could be getting a flash of liquid in to the h.p. sw cap tube or it could be a bad h.p. control a good tech could tell the diff. in operation mode. i hope this helps you.
H.V.A.C.R IS COOL WHEN IT'S HOT
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| sgtjack
| "Re(1):ac high pressure goes off" , posted Mon 19 Jul 16:49
Do your self a favor and clean condenser ooil (outside unit) Many A/C cond units look clean (but are not). Use your garden hose and nozzel. After hosing dn unit "Do not start A/C unit until it is completly dry".
Later...
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| Xenos
Webmaster 
| "Re(1):ac high pressure goes off" , posted Thu 17 Jun 22:27
How much sub cooling do you have and what are the system pressures? I know you can’t answer this but this is the most likely thing to do and the answers we need. Doesn’t your contractor warrantee his work?
Xenos.
The best way to escape a problem is to solve it.
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| | samadams
| "Re(2):ac high pressure goes off" , posted Thu 17 Jun 23:24
by sub cooling do you mean if the room is cooled? once it is working the a/c cools room down to 68 degrees from 80 and is quick.
Mechanic now says the condenser fan motor might be faulty and requires replacing. He says after that we will know if other items also need replacement. Mechanic will be coming again tomorrow to service. I will go to the roof top with him. What can I ask and see? What are the normal pressure readings at what variables. Are these universal or specific for different models etc? Is there a general area of this problem that I should focus with the mechanic?
Thanks x
ss
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| | beginner
| "Re(3):ac high pressure goes off" , posted Thu 24 Jun 21:30
Check the condenser unit. Are the fan blades ok? Are the fins clean? What about the fan motor? Is it working properly?
Any of these can cause high cut off.
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| | Xenos
Webmaster
| "Re(3):ac high pressure goes off" , posted Fri 18 Jun 07:48
Sub cooling is the temperature difference between the saturation temperature and the actual temperature of the refrigerant. This will tell us when the phase change is ending in you condenser. If the phase change is ending too early the system can run at too high a pressure.
Xenos.
The best way to escape a problem is to solve it.
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| | MasterTech
| "Re(4):ac high pressure goes off" , posted Fri 17 Jun 20:11
I'd make sure the outside coils were clean. It may be over charged. WOuld this be a Ruud/Rheem outside unit? Noramlly when i see a fan motor going out the motor starts looking brown from over heating. And fan motors normally wont last long before they quit.
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| | MasterTech
| "Re(5):ac high pressure goes off" , posted Fri 17 Jun 20:26
No Sub cool is the amout of heat removed after saturation point of the freon. It is read at the condenser unit. Temperature read at the liquid line(small normally 3/8copper) and take the difference of the head pressure temperature.
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