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87
Table 79 — Humidi-MiZer
®
Service Analysis
PROBLEM
CAUSE
REMEDY
Subcooling Mode Will Not
Activate
Circuit A compressors unavailable for 020-
027 units. Circuit B compressors unavail-
able for 030-060 units
Check alarm history for general cooling mode operation problems.
See Table 78.
Check for compressors locked out.
General Cooling Mode problem
See Table 78.
Humidi-MiZer relative humidity sensor not
functioning - RARH, SPRH, or field
installed RH sensor
Check that a relative humidity sensor is connected and that the
appropriate sensor is configured in the unit software, (Configura-
tion
DEHU
D.SEN). See Table 69.
Check for 24VDC from CEM (RARH, SPRH).
Check 4 to 20 mA signals from sensor.
Humidi-MiZer temperature sensors not
functioning - SAT, CCT
See Thermistor Troubleshooting section on page 84.
No Dehumidification demand
See “No Dehumidification Demand,” below.
3-way valve malfunction
See “3-Way Valve Malfunction.”
Unit control software is not configured for
Humidi-MiZer system
Check that the unit is configured for Humidi-MiZer (Configuration
DEHU
D.SEL).
Reheat Mode Will Not Activate
Circuit A compressors unavailable for 020-
027 units. Circuit B compressors unavail-
able for 030-060 units
Check alarm history for general cooling mode operation problems.
See Table 78.
Check for compressors locked out.
Humidi-MiZer relative humidity sensor not
functioning - RARH, SPRH, or field
installed RH sensor
Check that a relative humidity sensor is connected and that the
appropriate sensor is configured in the unit software, (Configura-
tion
DEHU
D.SEN). See Table 69.
Check for 24 VDC from CEM (RARH, SPRH).
Check 4 to 20 mA signals from sensor.
No Dehumidification demand
See “No Dehumidification Demand,” below.
3-way valve malfunction
See “3-Way Valve Malfunction.”
Unit control software is not configured for
Humidi-MiZer system
Check that the unit is configured for Humidi-MiZer (Configuration
DEHU
D.SEL).
No Dehumidification Demand
Relative Humidity setpoint is too low - dis-
crete input (Humidistat, Thermidistat, etc.)
Check/reduce setting on discrete humidity input device.
Relative Humidity setpoint is too low - RH
sensor
Check the dehumidification relative humidity setpoint (Configura-
tion
DEHU
D.RH.S)
Software configuration error for the type of
relative humidity sensor being used
Check that the unit software is configured for the correct relative
humidity sensor (Configuration
DEHU
D.SEN). D.SEN = 1:
Return Air 2: Discrete Input. See page 74.
No humidity signal
Check wiring and sensor.
3-Way Valve Malfunction
No 24V signal to input terminals
Check using Service Test mode.
Check wiring.
Check transformer and circuit breakers.
Check RCB relay output.
Solenoid coil burnout
Check continuous over-voltage is less than 10%.
Check continuous under-voltage is less than 15%.
Check for missing coil assembly parts.
Replace solenoid coil.
Stuck valve
Replace valve. Replace filter drier.
Unit Initiates a Humidi-MiZer
Reheat Mode, but Supply Air
Temperature is Overheating/
Overcooling the Space
Humidi-MiZer Vent Reheat Setpoint is too
low
Check the Vent Reheat Setpoint Selection (Configuration
DEHU
D.V.CF) and Vent Reheat Setpoint (Configuration
DEHU
D.V.HT). If used, check the Vent Reheat RAT Offset also
(Configuration
DEHU
D.V.RA). See Table 69 for Humidi-MiZer
controls set-up.
Evaporator discharge temperature (CCT)
or supply air temperature (SAT) thermistor
is reading incorrectly.
See Thermistor Troubleshooting section on page 84.
Check if SAT thermistor is in a location that is measuring stratified
air.
Valve controlling gas bypass around the
condenser is not functioning properly
See " Modulating Valves Not Functioning Properly"
Valve controlling refrigerant flow to the con-
denser is not functioning properly
See " Modulating Valves Not Functioning Properly"
Modulating valves are not calibrated properly Run valve calibration through Service Test.
Unit control software indicates a Humidi-
MiZer Reheat Mode, but the 3-way valve is
not functioning properly
See " 3-Way Valve Malfunction"
Unit is not sized to meet the load at the cur-
rent entering air and outdoor conditions.
Check product data tables or ECAT for rated capacity at current
entering air and outdoor conditions.
Summary of Contents for WEATHERMAKER 48A2020
Page 112: ...112 Fig 20 Typical Main Control Box Wiring Schematic 48 50A Units ...
Page 113: ...113 Fig 21 Typical Auxiliary Control Box Wiring Schematic ...
Page 114: ...114 Fig 22 Typical 2 Stage Gas Heat Wiring Schematic Size 060 Units Shown ...
Page 115: ...115 Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown TO NEXT PAGE ...
Page 116: ...116 Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown cont ...
Page 117: ...117 Fig 24 Typical Electric Heat Control Schematic 50 Series Size 060 Units Shown ...
Page 118: ...118 Fig 25 Typical Controls Option Wiring Schematic SW1 SW2 OR DEHUMIDIFY SWITCH ...
Page 119: ...119 Fig 26 Typical Power Schematic 48 50A2 A3 A4 A5 060 Unit Shown ...
Page 120: ...120 Fig 27 Typical Power Schematic of Greenspeed Low Ambient Option 48 50A 060 Unit Shown ...
Page 121: ...121 Fig 28 Typical Small Chassis Component Location Size 020 035 Units ...
Page 122: ...122 Fig 29 Typical Large Chassis Component Locations Size 040 060 Units ...
Page 185: ...185 APPENDIX C VFD INFORMATION cont Fig F Internal Enclosure Fan Replacement A48 7716 ...