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Fault
Main power Problems
HP Fault-Code 2
High pressure
LP/LOC Fault-Code 3
Low Pressure/Loss of Charge
FP1 Fault - Code 4
Water Coil low
temperature limit
FP2 fault - Code 5
Air Coil low
temperature limit
Condensate Fault-Code 6
Over/Under Voltage-
Code 7
(Auto resetting)
Unit Performance
Sentinel-Code 8
No Fault Code Shown
Unit Short Cycles
Only Fan Runs
0
FUNCTIONAL TROUBLESHOOTING
Htg Clg Possible Cause
X
X
Green Status LED Off
X
Reduced or no water flow
in cooling
X
Water Temperature out of range in
cooling
X
Reduced or no Air flow
in heating
X
Air Temperature out of range in
heating
X
X
Overcharged with refrigerant
X
X
Bad HP Switch
X
X
Insufficient charge
Compressor pump down at start-
X
up
X
Reduced or no water flow
in heating
X
Inadequate anti-freeze level
X
Water Temperature out of range
X
X
Bad thermistor
X
Reduced or no Air flow
in cooling
X
Air Temperature out of range
Improper temperature limit setting
X
(30°F vs 10°F)
X
X
Bad thermistor
X
X
Blocked Drain
X
X
Improper trap
X
Poor Drainage
X
Moisture on sensor
X
X
Under Voltage
X
X
Over Voltage
X
Heating mode FP2>125°F
Cooling Mode FP1>125°F OR
X
FP2< 40°F
X
X
No compressor operation
X
X
Compressor Overload
X
X
Control board
X
X
Dirty Air Filter
X
X
Unit in "Test Mode"
X
X
Unit selection
X
X
Compressor Overload
X
X
Thermostat position
X
X
Unit locked out
X
X
Compressor Overload
X
X
Thermostat wiring
Solution
Check Line Voltage circuit breaker and disconnect
Check for line voltage between L1 and L2 on the contactor
Check for 24VAC between R and C on CXM
Check primary/secondary voltage on transformer
Check pump operation or valve operation/setting
Check water flow adjust to proper flow rate
Bring water temp within design parameters
Check for dirty air filter and clean or replace
Check fan motor operation and airflow restrictions
Dirty Air Coil- construction dust etc.
Too high of external static. Check static vs blower table
Bring return air temp within design parameters
Check superheat/subcooling vs typical operating condition
table
Check switch continuity and operation. Replace
Check for refrigerant leaks
Check charge and start-up water flow
Check pump operation or water valve operation/setting
Plugged strainer or filter. Clean or replace.
Check water flow adjust to proper flow rate
Check antifreeze density with hydrometer
Bring water temp within design parameters
Check temp and impedance correlation per chart
Check for dirty air filter and clean or replace
Check fan motor operation and airflow restrictions
Too high of external static. Check static vs blower table
Too much cold vent air? Bring entering air temp within
design parameters
Normal airside applications will require 30°F only
Check temp and impedance correlation per chart
Check for blockage and clean drain
Check trap dimensions and location ahead of vent
Check for piping slope away from unit
Check slope of unit toward outlet
Poor venting. Check vent location
Check for moisture shorting to air coil
Check power supply and 24VAC voltage before and during
operation.
Check power supply wire size
Check compressor starting. Need hard start kit?
Check 24VAC and unit transformer tap for correct power
supply voltage
Check power supply voltage and 24VAC before and during
operation.
Check 24VAC and unit transformer tap for correct power
supply voltage
Check for poor air flow or overcharged unit.
Check for poor water flow, or air flow
See "Only fan operates"
Check and Replace if necessary
Reset power and check operation
Check and Clean air filter
Reset power or wait 20 minutes for auto exit.
Unit may be oversized for space. Check sizing for actual
load of space.
Check and Replace if necessary
Insure thermostat set for heating or cooling operation
Check for lockout codes. Reset power.
Check compressor overload. Replace if necessary.
Check thermostat wiring at heat pump. Jumper Y and R
for compressor operation in test mode.
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Table of Contents
Troubleshooting
