data aire nuisance trip
i HAVE A dATA AIRE SPLIT UNIT THAT RANDOMELY TRIPS ON HI HEAD PRESSURE FOR NO APPARENT REASON. WHEN I SAY RANDOM , I MEAM RANDOM. UNIT RUNS FINE FOR WEEKS, AND THEN WILL TRIP OUT SEVERAL DAYS IN A ROW. THE CONDENSER FAN MOTOR WAS CHANGED A YEAR AGO AND THERE WHERE NO ISSUES UNTIL RECENTLY. I REPLACED THE CONDENSER FAN AND THE UNIT UNIT TRIPPED OUT AFTER THREE DAYS. THE HEAD PRESSURE SWITCH WORKS FINE. THIS IS SUCH A RANDOM OCCURENCE I HAVE YET TO ACTUALLY SEE IT HAPPEN PERSONALLY. THERE IS A P66 FAN CYCLE ON THE UNIT WHICH APPEARS TO WORK PROPERLY. I BLOCKED THE CONDENSER COILS AND THE FAN MOTOR SPEED INCREASED AND DECREASED WHEN I UNBLOCKED THE COIL
ANY SUGGESTIONS WOULD BE APPRECIATED.
Data aires have manual resest HP switches on each circuit. Are you having to reset that switch ?
Put a set of guages on it and check head pressure . Have someone kill the condensing unit and and see if switch is tripping early.
Ive got 70 Data Aires.
Its either a weak switch or a fan motor intermittantly cutting out due to thermal ovld
The first thing to check is the refrigerant charge in the system per the Data Aire IOM. The subcooling should be between 8 and 10 degrees. Also check the upper bearing on the motor, if there is any play in the shaft that is noticeable the motor will need to be replaced.
The P-66 is very hard on motor life spans due to the operation of the component. The P-66 lowers the voltage to the motor to reduce the fan speed to maintain a minimum head pressure during cool/cold ambients. This in turn can cause the motor to overheat. That heat is what shortens the life of the bearing and motor.
A general rule of thumb with any unit that is equiped with a P-66 or P-266 fan speed controller is to only use a OEM replacement motor.
I had the exact same situation on a data-aire. After a long off period the thing would trip the head pressure switch on startup. It seemed to be logging liquid in the discharge line, just off the compressor. After verifying the charge, fan motors, head pressure controls & CC heater were all good, we called Data-aire directly. One of the other techs followed up on this, so I'm not exactly sure what he did. They had him adjust one of the valves, the hot gas bypass I think. There's also a txv type valve in the lower right side of the pic I attached. I'm not sure what it's for, maybe liquid injection? There's also a head master on this system, but that's non-adjustable to my knowledge. Anyway, during low ambient situations one of those valves was leaking liquid back to the compressor discharge tube and spiking head pressure to like 400 psi for just an instant, long enough to trip the switch. Weird. If you have the same setup you might want to check it out.
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