Coil temperature sensor fault. If this sensor fails, the manual says defrost occurs at each time interval during heating and terminates after 2 minutes.
Bryant outdoor 55 is a coil temperature sensor fault. The manual wants the thermistor clipped to the distributor entry tube, the harness checked, and the outdoor control replaced only if its hardware is damaged. If this sensor fails, defrost runs at each interval in heating and stops after 2 minutes. That short defrost is why a heat pump can feel like it is not heating. Code 53 is the outdoor air sensor, which fails over to a different defrost rule.
Likely causes
- Sensor harness not connected to the outdoor control
- Broken or loose harness wire
- Thermistor not clipped to the distributor entry tube, or in the wrong location
- Broken or damaged sensor, or hardware damage to the outdoor control
Safe checks for 55
- Count 5 short flashes and 5 long flashes. A two-minute defrost, every interval, will not keep the outdoor unit clear in a hard freeze. That is the manual's failover, not a charge you can add
- Technicianclip the sensor to the distributor entry tube, check the harness, and replace the outdoor control only if its hardware is damaged
Capacitors can hold a charge after the power is off. Safety terms.
When to call a pro
Call a licensed HVAC technician if 55 is flashing and the heat pump is not keeping up. Do not hose an energized outdoor unit.
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