Daikin Condensing Unit DX13SA0421AE

Warning: This procedure requires trained personnel with PPE!

Reversing valve stuck in the mid-position?

Measure the suction line temperature through the reversing valve

Valve changes position when switching from COOLING to HEATING cycle?

Measure the voltage at the valve coil terminals during COOLING cycle

Voltage registered at the coil terminals?

Continuity of the connecting wiring from the “O” terminal of the thermostat to the unit?

Sign off on the reversing valve / solenoid check

WARNING: Disconnect ALL power before servicing.

Remove the wiring from the control terminals.

Using an ohmmeter, test for continuity across the normally closed contacts. No reading indicates the control is open.

Make sure the limits are cool before testing.

If found open, replace. Do not wire around.

Sign off on the heater limit control check

Warning: This procedure requires trained personnel with PPE!

Fuse, circuit breaker, ground fault protective device tripped?

If the protective device has tripped, an electrical problem exists and must be corrected.

Check the circuit protective device rating. It should coincide with the equipment nameplate.

Did the circuit breaker open again after resetting?

If it opens again, DO NOT continue to reset.

Disconnect all power to unit, ensuring all power legs are open.

DO NOT remove protective terminal cover. Disconnect the three leads going to the compressor terminals at the nearest point to the compressor.

Warning: This procedure requires trained personnel with PPE!

Attach a photo of the thermometer or thermocouple type temperature tester attached to the liquid line as it leaves the condensing unit.

Attach a photo of the high side pressure gauge installed on the high side (liquid) service valve at the front of the unit.

Record the temperature of the line.

Enter the design subcooling obtained from the technical information manual or specification sheet for the model being serviced.

Enter the hi-pressure reading from the “Required Liquid Line Temperature” chart.

Enter the liquid line pressure gauge reading.

Enter the temperature from the Temperature - Pressure Chart.

Remove outer case, control panel cover, etc., from unit being tested. WARNING: Line Voltage now present.

Measure the voltage across terminals L1 and L2 of the contactor for the condensing unit or at the field connections for the air handler or heaters.

If no reading, indicates open wiring, open fuse(s) no power or etc., from unit to fused disconnect service. Repair as needed.

With ample voltage at line voltage connectors, energize the unit.

Measure the voltage with the unit starting and operating, and determine the unit Locked Rotor Voltage.

Locked Rotor Voltage is the actual voltage available at the compressor during starting, locked rotor, or a stalled condition. Measured voltage should be above minimum listed in chart below.

To measure Locked Rotor Voltage attach a voltmeter to the run 'R' and common 'C' terminals of the compressor, or to the T1 and T2 terminals of the contactor. Start the unit and allow the compressor to run for several seconds, then shut down the unit. Immediately attempt to restart the unit while measuring the Locked Rotor Voltage.

Does the locked rotor voltage read within the voltage tabulation as shown?