Carrier Aquazone 50PCH PCV 007 Installation, Start-Up And Service Instructions Manual page 64

FAULT COOLING
No fan operation
X
(PSC motor)
No fan operation
(constant torque X
motor)
No fan operation
(constant airflow X
motor)
Unit not shifting
X
into cooling
Excessively cold
supply air
temperature in
cooling or
X
excessively hot
supply air
temperature in
heating
Excessively warm
supply air
temperature in
X
cooling and/or
excessively cool air
in heating
High humidity X
X
Objectionable noise
levels
X
X
Table 33 — Troubleshooting (cont)
HEATING CHECK
Fan relay energized Faulty motor
X
No fan operation signal
Fan relay not
energized
Bad fan relay
No fan operation signal
Loose wiring
X
Faulty motor
No fan operation signal
Loose wiring
Interface board problems
X
Faulty motor
Reversing valve
Faulty solenoid
solenoid energized
Miswired/faulty
thermostat
Reversing valve
solenoid not
energized
Loose wire on "O"
terminal
Dirty Filter
Fan speed too low
X Reduced airflow
Excessive duct pressure drop
Airflow too high Fan speed setting too high
High or low water Inlet water temperature out of
temperature range
X
Air leakage Leaky ductwork
Loss of refrigeration
Low refrigerant
capacity
Fan speed setting too
Airflow too high
high
Loss of refrigeration
Low refrigerant
capacity
Unit oversized
Short cycling
Poor thermostat location
Poor ductwork/grille design
Air noise
Fan speed setting too high
Unit not mounted on full vibration
pad
X
Unit not connected with flexible
Structure Bourne
conduit, water lines and/or
noise
ductwork
Unit cabinet touching wall or other
building component
High water temperature or low
water flow rate elevating head
pressure
Scaled or fouled water coil
Compressor noise
elevating heat pressure
Low airflow elevating head
X
pressure
X Water hammer Fast closing valves installed
POSSIBLE CAUSE
Check supply voltage from the fan relay to the motor. Check
that all motor wires are secure. With power off spin the motor
shaft - noise, resistance or uneven motion can be signs of
motor failure.
Check for 24 VAC across the fan relay coil. Check all wiring
connections.
If the relay coil is energized but the relay does not pull in,
check the resistance across the relay coil - an open circuit is
an indicator of a faulty relay.
Check for 24 VAC between "G" and "C". Check all wiring
connections.
Check all wiring connections at motor and control box.
Check supply voltage to the motor. Check that all motor wires
are secure. With power off spin the motor shaft - noise,
resistance or uneven motion can be signs of motor failure.
Check for 24 VAC between "G" and "C". Check all wiring
connections. Make sure that the thermostat connection plug is
securely connected.
Check all wiring connections at motor and control box. Check
that power and control harnesses are securely connected.
Make sure that the interface board is not damged and that all
DIP switches are in the proper configuration (refer to the
blower performance tables).
Check supply voltage to the motor. Check that all motor wires
are secure. Move the "TEST" DIP switch to "ON" and the
other switches to "OFF" on the "ADJUST" switch block on the
interface board - the motor should run at 70% torque when
"G" is called. With power off spin the motor shaft - noise,
resistance or uneven motion can be signs of motor failure.
Check that the reversing valve solenoid is receiving 24 VAC. If
so, check the resistance of the solenoid - an open circuit may
indicate a burned out solenoid.
Check that the reversing valve thermostat wire is connected
to the "O" terminal of the thermostat. Check for a contact
closure between "O" and "R".
Check that the wires from the thermostat to the unit are
securely connected and that the wires from the electrical box
to the reversing valve are connected.
Replace filter.
Consult blower performance table and increase fan speed if
possible.
Consult blower performance table and increase fan speed if
possible.
Consult blower performance table and reduce fan speed if
possible.
Check unit capacity vs. water temperature.
Inspect ductwork.
Check refrigerant pressures with gauge set.
Consult blower performance table and reduce fan speed if
possible.
Check refrigerant pressures with gauge set.
Check unit performance against building load calculations.
Make sure that thermostat is not located by a supply- air duct.
Ensure ductwork and grilles are properly sized for unit airflow.
Consult blower performance table and reduce fan speed if
possible.
Mount unit on a vibration pad.
Install unit in accordance with instructions.
Adjust unit location to avoid unit touching structure.
Increase water flow rate and/or reduce water temperature if
possible.
Clean/descale water coil.
Check filter.
Increase fan speed.
Change valves to slow-close type.
64
SOLUTION