The high pressure limit/safety needs to be reset frequently before reaching the set temp of 76 degrees faren. outside temp is 83 degrees and actual inside temp is 80 degrees. it use to cool down and achieve the set point temp and the indoor unit cycling would be short sustaining the indoor set temp. now, the condenser shuts off before reaching the set point for the 1st time due the the tripped high pressure limit/safety switch. it needs to be reset by pressing the red button at the condenser and the condenser will start up again. it needs to be reset about 3 times during the course of a night
Is the outdoor fan running? The fan cools the coils and compressor, therefore keeping the high pressure low enough to run. Either the fan is not working or its not spinning fast enough. Check the capacitor, or just replace it.
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SOURCE: frequent tripping of the hight limit switch
The high limit switch itself is getting weak , replace it and problem solved!
SOURCE: [email protected] has more info as requested
Hello kamper2 - Sorry for the delay in answering. I had a response prepaired but something cleared it on me about 2AM last night and I just couldn't think any more. Sounds like your problem is similar but different. I don't think you have to spend any more time on the roof looking at the roof unit. I have been working with a tech and Dometic for over 6 weeks. Right now I am running my A/C on an extension cord out my window and over the the power pedestal for power. The 12 VDC to the A/C circuit board is coming from a car battery sitting on my kitchen floor. The communication cable is a 25' telephone extension cord draped over my kitchen slide over to the CCC. Last week end I turned off all power to the trailer (110VAC and 12VDC) and sat here all day running just the A/C. It shut down 6 times. This was an effort by Dometic to eliminate RF energy affecting the microprocesser on the A/C control circuit board. Apparently the CCC and A/C control circuit board have some idiosyncrasies that aren't well explained. I also have an extended warranty on my A/C with Dometic. I'm thinking they believe RF energy may be picked up via the communication cable and affecting the microprocessor. Do you have a cell phone, wireless router for your computer or telephone or something that may put out noticeable RF energy? If you do, turn it off for a while to see if that may be related to the shut down's. I'm still working on my problem and no solution or reason yet. The circuit board in my A/C has already been replaced. I am assuming you do not have an icing problem with the problem A/C. If for some reason you decide to replace the communication cable from the CCC to the A/C circuit board, be aware that a typical telephone extension cord will not work. You must replace one of the plugs so the wires are straight through (pin for pin) and not reversed as the typical telephone extension cord is. Good luck with your detective work! azbill375
SOURCE: High Pressure cutoff
YOUR OUTDOOR FAN MOTOR SHOULD NEVER SHUT OFF IN THE AC MODE. IT IS SUPPOSED TO SHUT OFF IN THE HEAT MODE WHEN ITS IN DEFROST. IF THE UNIT IS RUNNING IN COOL AND THE OUTSIDE MOTOR QUITS ,THE COMPRESSOR WILL QUIT SOON AFTER. EITHER THE RUN CAPACITOR FOR THE FAN IS BAD OR THE FAN MOTOR ITSELF IS BAD, IF CAP IS GOOD THEN THE MOTOR IS At FAULT. THE OUTDOOR PRESSURE SWITCH CAN ALSO OPEN IF THE INDOOR FAN MOTOR FAILS IN HEAT OR THE FILTER IS PLUM NASTY in heat OR THE INDOOR COIL IS PLUGGED UP in heat.. THE PRESSURE SWITCH USUALLY TRIPS AT 400 TO 425 SO ITS WORKING CORRECTLY. YOU MAY BE CONFUSING THE ISSUE SAYING THAT THE AIR IS HOT AND COLD INSIDE. IT IS COLD WHEN AC IS RUNNING HOT WHEN HEAT PUMP IS RUNNING IN HEAT BUT ESSENTIALLY not cold or hot if compressor isn't running, but a lot of folks describe the lack of cold air as hot when the compressor isnt running. but it basically is warm or house air temp.you test the capacitor with a capacitor tester or take it to motor shop and let them test it. odds are its a 5 , 7.5 or a 10. it should test within 10 % of rated value . ask for a RESCUE brand replacement motor. they are great ,reversable etc.carefully oil and sand the motor shaft and note exactly where the blade was located in relation to the grill so you get it back just the same. usually they wire up black to a leg of 220 power. white to the other leg of 220 power. brown and brown with white stripe to the capacitor.you can also pull whole fan shroud assembly on some units and take whole thing to motor shop and let them test motor cap, replace and all you do is return to unit and connect two power leads,
SOURCE: a/c shuts down after about 30 seconds
Sounds to me either a low refrigerant charge or low air volume over the evap coil (inside). There is a sencer for temps outside maybe it's tripping out on that.
SOURCE: pressure in both lines fluctuate from 140psi to below 30psi
The foreign made market is different than the USA.
First if the unit doesn't get a change or input from a manual command (on the remote on mine) it will shut off because it assumes there is no one there.
2nd if it is in the timer mode it may be different in orientation than what you are used to looking at.
TO make sure these are not your problem review the instructions.
If this is R22 or R410A there is not a pressure switch that will cut it "OFF" at 140#. And if your fluctuating tween 30 and 140 It is almost sure its low on charge especially if its new. Now I assume you mean 140 on the high side, right?
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