High Compressor Discharge Temperature Shutdown

Common Symptoms

• Display Module shows alarm 00017 and the unit shuts down the compressor
• Red shutdown alarm light is illuminated on the unit
• Refrigerated compartment temperature begins rising after compressor stops
• Unit may cycle back on briefly then shut down again on the same alarm
• Discharge line feels extremely hot to the touch near the compressor outlet
• Unit may have been running in high ambient temperatures or under heavy load before shutdown
• Alarm log viewable via the MENU key shows 00017 as most recent or repeated entry

Probable Causes (Ranked by Likelihood)

• Low refrigerant charge causing the compressor to run unloaded with insufficient cooling of discharge gas Very Likely
• Faulty or stuck-closed liquid injection solenoid not supplying refrigerant cooling to the compressor body Very Likely
• Failed or weak compressor discharge temperature sensor (thermistor) giving a false high reading Likely
• Restricted or clogged condenser coil reducing heat rejection and driving up head pressure and discharge temps Likely
• Condenser fan motor or blade failure reducing airflow across the condenser Likely
• Overcharge of refrigerant or non-condensables (air/moisture) in the system causing abnormally high head pressure Possible
• Internally worn or damaged compressor with excessive internal bypass (high compression ratio producing excess heat) Less Likely

Step-by-Step Diagnostic Procedure

1. Check the alarm log first. Press MENU on the Display Module and scroll to the alarm history. Note how many times 00017 has logged and whether other codes like high discharge pressure or low suction pressure appear alongside it. That combination points strongly to a refrigerant charge problem.

2. Inspect the condenser coil and fan section visually before anything else. Look for debris, dirt buildup, bent fins, or a fan blade that is broken or spinning the wrong direction. A plugged condenser is a common cause and takes only a few minutes to rule out. Clean the coil with water or compressed air if fouled.

3. Check condenser fan motor operation. With the unit running in RUN mode, verify the condenser fan is spinning at full speed and in the correct direction (pulling air through the coil). A weak or intermittent fan motor will cause discharge temps to spike in warm ambient conditions.

4. Locate the discharge temperature sensor (thermistor) on the compressor discharge line, typically within 6 inches of the compressor outlet. Disconnect it and measure resistance with a multimeter. Compare the reading to the temperature-resistance chart in the service manual. At 70 degrees F (21 C) a good sensor typically reads approximately 10,000 ohms. A reading of zero, open circuit, or wildly out of range means replace the sensor before further diagnosis.

5. Check refrigerant sight glass condition. With the unit running, look at the sight glass on the liquid line. Bubbles or a completely clear (vapor-only) glass indicates low refrigerant charge. Low charge is the most common trigger for 00017. Recovering, weighing, and recharging the system requires EPA certification and refrigerant recovery equipment. Call a certified refrigerant tech if you see bubbles.

6. Inspect the liquid injection solenoid valve if the unit is equipped with one. This valve injects liquid refrigerant into the compressor body to cool it during high-load conditions. With the unit running at high load, you can carefully feel the liquid injection line for flow (it should feel cool). A stuck-closed solenoid or clogged strainer on the injection port means the compressor has no internal cooling. Swap the solenoid coil first since that is the easiest part to test.

7. Measure head pressure using a refrigerant gauge set on the high-side service port. Normal high-side pressure depends on refrigerant type and ambient temperature but abnormally high head pressure (for R-404A, above 350 psig at moderate ambient) combined with high discharge temp points to condenser restriction, overcharge, or non-condensables. This step requires a gauge manifold set and refrigerant certification.

8. If sensor checks, condenser, fans, and refrigerant charge all check out, suspect internal compressor wear. An internally bypassing compressor works harder, generates more heat, and will repeatedly trigger 00017. A compressor compression test or amp-draw comparison to spec is needed. This is an advanced diagnosis, call a Carrier Transicold certified technician.

Frequently Asked Questions