![background image](http://html1.mh-extra.com/html/mars/comfort-aire-century-he-series/comfort-aire-century-he-series_installation-operation-and-maintenance-manual_1730528052.webp)
52
Installation, Operation & Maintenance - HEH/HEV Series
Functional Troubleshooting
Fault
Htg Clg Possible Cause
Solution
Main power problems
X
X
Green Status LED Off
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/DXM'
Check primary/secondary voltage on transformer.
HP Fault
Code 2
High Pressure
X
Reduced or no water flow in cooling
Check pump operation or valve operation/setting.
Check water flow adjust to proper flow rate.
X
Water Temperature out of range in cooling
Bring water temp within design parameters.
X
Reduced or no air flow in heating
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.
X
Air temperature out of range in heating
Bring return air temp within design parameters.
X
X
Overcharged with refrigerant
Check superheat/subcooling vs typical operating condition table.
X
X
Bad HP Switch
Check switch continuity and operation. Replace.
LP/LOC Fault
Code 3
Low Pressure / Loss of Charge
X
X
Insufficient charge
Check for refrigerant leaks
X
Compressor pump down at start-up
Check charge and start-up water flow.
LT1 Fault
Code 4
Water coil low
temperature limit
X
Reduced or no water flow in heating
Check pump operation or water valve operation/setting.
Plugged strainer or filter. Clean or replace..
Check water flow adjust to proper flow rate.
X
Inadequate antifreeze level
Check antifreeze density with hydrometer.
X
Improper temperature limit setting (30°F vs
10°F [-1°C vs -2°C])
Clip JW3 jumper for antifreeze (10°F [-12°C]) use.
X
Water Temperature out of range
Bring water temp within design parameters.
X
X
Bad thermistor
Check temp and impedance correlation per chart
LT2 Fault
Code 5
Air coil low
temperature limit
X
Reduced or no air flow in cooling
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.
X
Air Temperature out of range
Too much cold vent air? Bring entering air temp within design parameters.
X
Improper temperature limit setting (30°F vs
10°F [-1°C vs -12°C])
Normal airside applications will require 30°F [-1°C] only.
X
X
Bad thermistor
Check temp and impedance correlation per chart.
Condensate Fault
Code 6
X
X
Blocked drain
Check for blockage and clean drain.
X
X
Improper trap
Check trap dimensions and location ahead of vent.
X
Poor drainage
Check for piping slope away from unit.
Check slope of unit toward outlet.
Poor venting. Check vent location.
X
Moisture on sensor
Check for moisture shorting to air coil.
X
X
Plugged air filter
Replace air filter.
x
X
Restricted Return Air Flow
Find and eliminate restriction. Increase return duct and/or grille size.
Over/Under
Voltage Code 7
(Auto resetting)
X
X
Under Voltage
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.
X
X
Over Voltage
Check power supply voltage and 24VAC before and during operation.
Check 24VAC and unit transformer tap for correct power supply voltage.
Unit Performance Sentinel
Code 8
X
Heating mode LT2>125°F [52°C]
Check for poor air flow or overcharged unit.
X
Cooling Mode LT1>125°F [52°C] OR LT2<
40ºF [4ºC])
Check for poor water flow, or air flow.
Swapped Thermistor
Code 9
X
X
LT1 and LT2 swapped
Reverse position of thermistors
ECM Fault - Code 10
X
X
Blower does not operate
Check blower line voltage
Check blower low voltage wiring
Blower operating with incorrect airflow
Wrong unit size selection
Wrong unit family selection
Wrong motor size
Incorrect blower selection
Low Air Coil Pressure Fault
(ClimaDry) Code 11
X
Reduced or no air flow in cooling or ClimaDry
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
Air temperature out of range
Too much cold vent air - bring entering air temp within design parameters
Bad pressure switch
Check switch continuity and operation - replace
Summary of Contents for Comfort-Aire Century HE Series
Page 1: ...www marsdelivers com Installation Operation and Maintenance HEH HEV Series...
Page 32: ...32 Installation Operation Maintenance HEH HEV Series Typical Wiring Diagram Single Phase Unit...
Page 33: ...33 Installation Operation Maintenance HEH HEV Series Typical Wiring Diagram Three Phase Unit...
Page 34: ...34 Installation Operation Maintenance HEH HEV Series Typical Wiring Diagram 460 Volt Unit...