Overview:
First Defrost permit conditions after Power Up.
30 Minutes run time with the Outdoor Air Temp less than 52° and the Outdoor Coil Temp less than 33°.
Subsequent Defrosts permit conditions.
Outdoor Air Temp less than 52°, Outdoor Coil Temp less than 33°, the New Initiate DT Value is reached.
To view the sensor temperatures using the Symbio 700 On-Board User Interface.
Press Home, Down Arrow to Status
Press the Check Mark, then Down Arrow to System (for outdoor temp) or Refrigeration (for coil temp)
Press the Check Mark, then Down Arrow to “Outdoor Air Temperature Arbitrator” or “Coil Temperature Sensor”.
Sequence of Operation
The first defrost after a power cycle will occur after 30 minutes of run time under defrost permit conditions.
When the first defrost cycle has terminated, the board will track twelve (12) minutes to assure that a dry coil condition has been achieved.
At the twelve-minute point, a Dry Coil Temperature Differential (DCTD) will be calculated using the current values of OAT (outdoor air temp) minus OCT (outdoor coil temp).
Note: The OAT is expected to be higher than the OCT.
The (DCTD) value is then multiplied by 1.8 to calculate the New Initiate DT Value.
Once the New Initiate DT Value is reached, the next defrost cycle is initiated.
Defrost Termination
The defrost cycle is terminated when the Outdoor Coil Temperature (OCT) exceeds the Outdoor Temperature (ODT) +47°F.
The defrost termination temperature (DTT) will be limited between 57°F and 72°F.
Independent Circuit Defrost Operation
For Odyssey Independent Circuit Heat Pump units with two outdoor coil temperature
sensors, the unit will perform defrost per circuit based on its own coil temperature sensor value,
the outdoor ambient temperature, and the accumulated circuit run time.
At least one stage of auxiliary heat will be energized anytime either circuit is in defrost mode.
All other defrost functionality, including the diagnostic conditions, will perform as described above independently per circuit.
Default Mode
If any Defrost Fault is active, the unit will revert to the default mode any time the unit is in the active heat mode with compressors running.
If Both the Outdoor Air Sensor and the Coil Temperature Sensor fails, the unit will revert to the default mode any time the unit is in the active heat mode with compressors running.
If Either the Outdoor Air Sensor and the Coil Temperature Sensor fails, the unit will revert to the default mode if the other sensor is below the Defrost Permit Temperature.
Default Mode is 5-minute defrost cycle after each 30 minutes of cumulative compressor heating operation.
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.