105
Table 73 — Humidi-MiZer
®
Service Analysis
PROBLEM
CAUSE
REMEDY
Subcooling Mode Will Not
Activate
Circuit B compressors unavailable
Check alarm history for general cooling mode operation problems. See
Table 72.
Check for Circuit B compressors locked out.
General Cooling Mode problem
See Table 72.
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,
(
Configuration
DEHU
D.SEN).
See page 89.
Check for 24VDC from CEM (RARH, SPRH).
Check 4-20 mA signal from sensor.
Humidi-MiZer temperature sensors not
functioning - SAT, CCT
See “Thermistor Troubleshooting,” page 103.
No Dehumidification demand
See “No Dehumidification Demand,” below.
3-way valve malfunction
See “3-Way Valve Malfunction,” below.
Unit control software is not configured
for Humidi-MiZer system
Check that the unit is configured for Humidi-MiZer system
(Configuration
DEHU
D.SEL)
.
Reheat Mode Will Not Activate
Circuit B compressors unavailable
Check alarm history for general cooling mode operation problems. See
Table 72.
Check for Circuit B 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,
(Configuration
DEHU
D.SEN
). See page 89.
Check for 24 VDC from CEM (RARH, SPRH).
Check 4-20 mA signal from sensor.
No Dehumidification demand
See “No Dehumidification Demand,” below.
3-way valve malfunction
See “3-Way Valve Malfunction” below.
Unit control software is not configured
for Humidi-MiZer system
Check that the unit is configured for Humidi-MiZer
system
(Configuration
DEHU
D.SEL)
.
No Dehumidification Demand
Relative Humidity set point is too low -
discrete input (Humidistat,
Thermidistat, etc.)
Check/reduce setting on discrete humidity input device.
Relative Humidity set point is too low -
RH sensor
Check the dehumidification relative humidity trip point
(
Configuration
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:
RARH, 2:SPRH, 3: Discrete Input. See page 89.
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
Humid-MiZer Vent Reheat Set Point is
too low
Check the Vent Reheat Set Point 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 page 90 for
Humid-MiZer controls set-up.
Evaporator discharge temperature
(CCT) or supply air temperature (SAT)
thermistor is reading incorrectly.
See “Thermistor Troubleshooting,” page 103.
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
condenser 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
current 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 WeatherExpert 48N2
Page 135: ...135 Fig 18 48 50N Typical Power Schematic Nominal 075 Ton Unit Shown ...
Page 136: ...136 Fig 19 48 50N Typical Power Schematic Nominal Ton 90 150 Units Shown ...
Page 137: ...137 Fig 20 48 50N Main Base Board Input Output Connections ...
Page 138: ...138 Fig 21 48 50N RXB EXB CEM Input Output Connections a48 9307 ...
Page 139: ...139 Fig 22 48 50N EXV SCB Input Output Connections a48 9308 ...
Page 140: ...140 Fig 23 48N Typical Modulating Gas Heat Unit Control Wiring ...
Page 141: ...141 Fig 24 50N Typical Electric Heat Unit Control Wiring ...
Page 144: ...144 Fig 27 48N Typical Gas Heat Section Wiring Nominal Ton 120 to 150 Units ...
Page 145: ...145 Fig 28 48 50N Typical Power Component Control Wiring 460 v ...
Page 146: ...146 Fig 29 48 50N Component Control Wiring 575 v Nominal Ton 075 to 150 Units ...
Page 147: ...147 Fig 30 48 50N Component Arrangement Power Box ...
Page 148: ...148 Fig 31 48 50N Component Arrangement Control Box ...
Page 240: ...240 APPENDIX D VFD INFORMATION CONT Fig G VFD Bypass Wiring Diagram WHEN USED ...