Original message
| sanmb
 |  "System temp stuck at 77"
, posted Wed 10 Sep 21:33  
I have an office with a 3.5 ton system (Rheem condenser R-22) which is just under 2 years old and capillary tube air handler. It has worked fine since being installed until two weeks ago. Since then, the space temperature will not drop below +/- 77.
I've checked the unit and found:
High side pressure fluctuates between 290-330psi.
Low side pressure +/- 60psi.
Superheat +/- 4 degrees.
Temperature of liquid line at condenser +/- 84 degrees.
Temperature of suction line at condenser +/- 38 degrees.
Dry bulb air temp at condenser when checked was +/- 83 degrees.
Interior temp was 77 degrees with a RH of +/- 70.
Coils looked clean but are hard to view/service.
Any input would be very helpful.
Thanks
Scott
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Replies:
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| hitch54
| "Re(1):System temp stuck at 77" , posted Wed 8 Oct 07:39
The first thing you want to do before troubleshooting any system is to make sure your coils and filters are clean. Both will affect system pressures. Assuming they are is a BIG mistake. Next,check the operation of the condenser fan mtr. If it is working properly, during the cooling cycle,warm air should be blowing out the top. Little or no air would mean the fan is rotating in the wrong direction and isn't cooling the condenser properly. Some motors can over a period of time actually go bad,usually as a result of a bad capacitor, and begin turning in the opposite direction. The best way to test for a bad capacitor is to replace it with a new one. However, some Fluke meters have a capacitor tester on them and are very reliable. Assuming that your cond. fan mtr isn't the problem and your coils are clean, the only other possibility I can think of for high head press. and low to normal suction is a bad TEV or restriction of R-22 flow.
Have a GREAT day!
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| Jojo98
| "Re(1):System temp stuck at 77" , posted Wed 10 Sep 22:15
Witha discharge pressure of 330psi, I would wager that the condenser is dirty, and in need of a serious cleaning. Now, with the head pressure so high the suction pressure should be elevated also. So I wouldn't be surprised if after cleaning the condenser, the suction pressure will drop below frezzing temperature. You know what you're doing, service the equipment; if you have any doubts, call a service company and have PM the equipment, and be prepared for a surprise ie. the low suction temp.
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