Friedrich VRP Series Service & Parts Manual page 67

Diagnostic Codes
Diag Description
The Indoor Coil at sensor T1's location
20 reaches a temperature < 30°F and
remains there for 5 consecutive minutes
Unit cycles (heat or cool
21
demand) > 9 times per hour
Unit cycles (heat or cool
22
demand) < 3 times per hour.
23 Room Freeze Protection
The Discharge Air sensor is
24
reading above 185°F
25 Indoor Coil Restriction
26 Temperature is Beyond Operating Limits
27 Minimum Configuration not Met
28 Motor Board Critical Failure
Motor Board Indoor Fan Port Over
30
Current Protection
Motor Board Indoor Fan Port
31
Over Current Protection
Motor Board Compressor Port
32
Over Current Protection
67
TROUBLESHOOTING
Diagnostic Check point
1. Lower than usual IDB speeds.
2. Low refrigerant charge.
3. Low Ambient.
1. Unit is oversized for the space
2. Wall controller is placed in a position
where the temperature is grossly off of the
actual room condition.
This diagnostic test is used for testing
and non‑critical analysis only
The unit cycles heating or cooling
demand less than 3 times within an hour
1. The Indoor Ambient temperature is
below 40°F
2. Inadequate insulation in room or closet.
3. Wall Controller sensor is bad
4. T8 Sensor is bad
1. IDB is not operating when
electric heat is on.
2. Electric heat limit switches are failing.
If one thermistored coil is frozen while
another thermistored coil is not.
The T8 (Indoor Ambient) sensor reads
less than 0°F or greater than 130°F
"At least 1 of the following
1. Unit not provisioned.
2. Heater boad communication issue.
3. Motor board communication issue."
A circuit error occurred on the
board where it is unable to continue
safe operation. Multiple circuit
errors can cause this one error.
N/A.
N/A.
Intantaneous phase over current
protection on the compressor axis.
Solution
1. Ensure that the IDB is connected
properly and is operational.
2. Check that there is no blockage in the
duct work.
3. Check the filter.
4. Check for refrigerant leaks and
reprocess.
1. Ensure that the wall controller's
placement is "correct" based on room air
flow
1. Make sure the room is properly
insulated.
2. Ohm out T8 sensor and replace if
necessary. Refer to thermistor values
chart
3. Replace Wall Controller
1. Replace Electric Heat Element.
2. Verify operation of IDB, replace if
necessary
1. Make sure diagnostic 23 is activated and
perform solutions.
2. Make sure the room is properly
insulated.
No change.
Replace the motor board.
Make sure to check the ADEN
board error (blinky lights)
Diagnostic disabled.
Diagnostic disabled.
"This error should automatically correct
itself. If error persists:
1. Check compressor wires for any
damage.
2. Verify resistance of compressor (leg‑leg
and leg‑chassis).
3. Replace the motor board.
4. Replace compressor."