Carrier 40UV Installation, Start-Up And Service Instructions Manual page 23

Trouble
Unit Not Operating - Power On
Unit Operating - No Mechanical
Heating / Cooling
No Indoor Fan
Hot Water / Chilled Water Valve
Not Operational (Option)
Table 13 — Troubleshooting
Possible Cause
Unit mounted disconnect in the "OFF" position.
Unit mounted 3-speed selector switch in the "0"
position (if equipped with a 4-position switch).
Unit switched OFF in the microprocessor.
Delay on start set incorrectly.
Unit not in occupied mode.
Fire/smoke alarm tripped.
Tripped circuit breakers.
Loose mains or control wiring.
Occupancy sensor malfunction.
Hot water freeze protection (optional) stat tripped.
Heating/cooling not required.
No output from microprocessor.
DX Split Units Only: HP/LP pressure safety switch(es)
tripped (open).
DX Split Units Only: Internal overload switch on
compressor tripped (open).
Loose control wiring connections.
Tripped circuit breakers.
Low temperature unit lockout.
DX Split Units Only: Compressor faulty.
Condensate pan/pump float switch tripped.
Motor tripped on internal overload.
Fan not required.
No power to the fan.
Current sensor fault.
Heating not required.
Loose wiring connections.
Faulty heating actuator.
Isolation valves are open.
Check for DC control signal.
Turn the disconnect switch to the "ON" position.
Turn the 3-speed selector switch to the "1, 2, or 3"
position.
Consult microprocessor documentation.
Consult microprocessor documentation.
Consult microprocessor documentation, and consult
microprocessor occupied setpoints.
De-energize and re-energize unit.
Reset the tripped circuit breaker(s).
With power OFF from distribution panel inspect the
field wiring connections in the electrical panel.
Inspect connections beginning with sensor input from
the microprocessor.
Manually reset at stat.
Verify applicable set point with return air temperature.
Consult microprocessor documentation.
Inspect high and low system pressures and wiring.
Check for dirty filters in Heat Pump mode.
Wait for compressor motor windings to cool down
(This switch is automatic reset).
Inspect connections beginning with compressor output
from the microprocessor.
Reset the tripped circuit breaker(s).
Consult microprocessor setpoints.
Replace compressor.
Check condensate pan/pump and piping for blockage.
Let motor cool down and reset - possible bad motor or
blocked filter.
Consult microprocessor documentation, or set
thermostat to "ON". Check if unit is in unoccupied and
standby mode.
Check to make sure plugs are locked in place and all
pins are secure. Check for 24V control signal.
Make sure sensor is functioning correctly.
Consult microprocessor documentation.
Inspect connections beginning with valve output from
the microprocessor. Check to ensure 24V supply
power is present at actuator.
Replace actuator if faulty.
Check for additional external isolation valves.
Check for 2-10VDC signal from microprocessor.
23
Possible Remedy