Carrier Aquazone 50PTH024 Installation, Start-Up And Service Instructions Manual page 59

FAULT COOLING HEATING
X
X
X
No compressor
operation but fan
runs
X
X
X
X
Table 25 — Troubleshooting
CHECK POSSIBLE CAUSE
High Pressure fault - no or
low water flow
High Pressure fault - high
water temperature
Is fault LED
High Pressure fault - fouled
Blinking
or scaled water coil
1 time?
High Pressure fault - no or
X
low airflow
Low Pressure fault - no or
low airflow
Is fault LED
Low Pressure fault - low
Blinking
refrigerant
2 times?
Low Pressure fault - no or
low water flow
X
Low Pressure fault - low
refrigerant
Freeze fault, water coil - no
or low water flow
Is fault LED
Freeze fault - low water
X Blinking
temperature
3 times?
Freeze fault - low
refrigerant
Condensate fault - poor
drainage
Is fault LED
Blinking
4 times?
Condensate fault - blocked
return air
Brown out fault - low supply
voltage
Is fault LED Brown out fault -
X Blinking overloaded control circuit
5 times?
Brown out fault - bad
thermostat connection
Freeze fault, air coil - no or
low airflow
Is fault LED
Blinking
6 times?
Freeze fault, air coil -
blocked return air
Freeze fault, air coil - low
refrigerant
Thermostat not calling for
compressor operation
Bad thermostat connection
No fault LED -
X contactor not
energized
Loose wire to contactor coil
Burned out contactor coil
Open compressor overload
No fault LED - Poor wiring connections
X contactor
energized
Burned out compressor
Check water valves and/or pumps for proper operation.
Check for water coil blockage.
Check water temperature - is it in range?
Check for proper flow rate and water temperature, but
low water side temp rise in cooling.
Check fan motor for proper operation.
Check air filter.
Inspect air coil for dirt/debris.
Check ductwork - are dampers closed or blocked?
Check fan motor for proper operation.
Check air filter.
Inspect air coil for dirt/debris.
Check ductwork - are dampers closed or blocked?
Check refrigerant pressure with gauge set.
Check water valves and/or pumps for proper operation.
Check for water coil blockage.
Check for proper flow rate and water temperature, but
low water side temp drop in heating.
Check water valves and/or pumps for proper operation.
Check for water coil blockage.
Check water temperature - is it below 40°F entering? If
heat pump is connected to a closed loop with antifreeze
check that the "FREEZE 1" resistor on the Complete C
board has been cut to set the unit to antifreeze mode.
Check refrigerant pressure with gauge set.
Check condensate pan for high water level. Check drain
line for blockages, double trapping or inadequate
trapping.
Check condensate pan for high water level. Check air filter
and return air ductwork for blockage. Check that there is
adequate space between the return air opening and walls
or other obstructions on free return applications.
Check primary voltage - ensure it is within the limits
listed on the unit data plate.
Check control voltage - if it is below 18-v check accessories
connected to the unit and ensure that they do not exceed
the VA draw shown in Table 7 on page 35.
Check that thermostat wiring is proper gauge and length,
that it is not damaged and that all connections at the
thermostat and heat pump are secure.
Check fan motor for proper operation.
Check air filter.
Inspect air coil for dirt/debris.
Check ductwork - are dampers closed or blocked?
Check that there is adequate space between the return
air opening and walls or other obstructions on free return
applications.
Check refrigerant pressure with gauge set.
Ensure that the thermostat is on and calling for "Y".
Check "Y" connection from thermostat. Ensure that there
is 24 VAC between "Y" and "C".
Check wiring - ensure that there is 24 VAC across the
contactor coil.
Test contactor with 24VAC (between "R" and "C"). Ohm
contactor coil - an open circuit indicates a burned coil.
Check for supply voltage at the load side of the
contactor. For 3-phase models check phase rotation and
voltage at all 3-phases.
Look for signs of heat on the wiring insulation. Check
that all wiring connections are secure and properly
torqued.
Does compressor hum when power is applied? If not,
check the resistance of the compressor windings using
the values shown in the compressor characteristics
chart. Note that the compressor must be cool (70°F)
when checking the windings.
59
SOLUTION