47
Humidi--MiZer
t
Troubleshooting
Use the unit Scrolling Marquee display or a CCN device to view
the cooling status display and the cooling diagnostic display (see
Appendix A) for information on the cooling operation and the
related Humidi-MiZer
™
operation. Check the current alarms and
alarm history for any cooling alarm codes and correct any causes.
(See Table 12.) Verify any unique control configurations per
installed site requirements or accessories.
If alarm conditions are corrected and cleared, operation of the
compressors, fans, and Humidi-MiZer valves may be verified by
using the Service Test mode. (See Table 4.) In addition to general
cooling service analysis (See Table 14), see Table 15 for general
Humidi-MiZer service analysis.
NOTE
:
Wiring, operation, and charge are different on a
Humidi-MiZer unit compared to a standard unit.
Table 15 – Humidi-MiZer Service Analysis
PROBLEM
CAUSE
REMEDY
Subcooling Reheat Mode
Will Not Activate.
General cooling mode problem.
See Cooling Service Analysis (Table 14).
No dehumidification demand.
See No Dehumidification Demand, below.
CRC relay operation.
See CRC Relay Operation, below.
Circuit RH1 valve is not open.
See RH1 Valve Operation, below.
Circuit CV valve is not closed.
See CV Valve Operation, below.
Hot Gas Reheat Mode
Will Not Activate.
General cooling mode problem.
See Cooling Service Analysis (Table 14).
No dehumidification demand.
See No Dehumidification Demand, below.
CRC relay operation.
See CRC Relay Operation, below.
Circuit RH1 valve is not open.
See RH1 Valve Operation, below.
Circuit CV valve is not closed.
See CV Valve Operation, below.
Circuit RH2 valve is not open.
See RH2 Valve Operation, below.
Outdoor temperature too low.
Check Reheat2 Circuit Limit Temperatures
(Configuration
→
HMZR
→
RA.LO and RB.LO)
using
Comfort
Link
™
Scrolling Marquee.
No Dehumidification Demand.
Relative humidity setpoint is
too low — Humidistat
Check/reduce setting on accessory humidistat.
Relative humidity setpoint is
too low — RH sensor.
Check Space RH Setpoint (Setpoints
→
RH.SP)
using
Comfort
Link Scrolling Marquee.
Software configuration error
for accessory humidistat.
Check Space Humidity Switch (Configuration
→
UNIT
→
RH.SW) using
Comfort
Link Scrolling Marquee.
Software configuration error
for accessory humidity sensor.
Check RH Sensor on OAQ Input (Configuration
→
UNIT
→
RH.S) using
Comfort
Link Scrolling Marquee.
No humidity signal.
Check wiring. Check humidistat or humidity sensor.
CRC Relay Operation.
No 24V signal to input terminals.
Check using Cool
→
Reheat1 Valve Test (Service Test
→
HMZR
→
CRC)
using
Comfort
Link Scrolling Marquee.
Check MBB relay output.
Check wiring.
Check transformer and circuit breaker.
No power to output terminals.
Check wiring.
Relay outputs do not change state.
Replace faulty relay.
CV or RH1 Valve Operation.
(NOTE: Normally Open
When De-energized)
No 24V signal to input terminals.
Check using Cool
→
Reheat1 Valve Test (Service Test
→
HMZR
→
CRC)
using
Comfort
Link Scrolling Marquee.
Check CRC Relay Operation.
Check Wiring.
Check transformer and circuit beaker or fuses.
Solenoid coil burnout.
Check continuous over-voltage is less than 10%.
Check under-voltage is less than 15%.
Check for missing coil assembly parts.
Check for damaged valve enclosing tube.
Stuck valve.
Replace valve. Replace filter drier.
RH2 Valve Operation.
(NOTE: Normally Closed
When De-energized)
No 24V signal to input terminals.
Check using Cool
→
Reheat1 Valve Test (Service Test
→
HMZR
→
RHV.A or
RHV.B) using
Comfort
Link Scrolling Marquee.
Check MBB relay output.
Check wiring.
Check transformer and circuit breaker or fuses.
Solenoid coil burnout.
Check continuous over-voltage is less than 10%.
Check under-voltage is less than 15%.
Check for missing coil assembly parts.
Check for damaged valve enclosing tube.
Stuck valve.
Replace valve. Replace filter drier.
Low Latent Capacity in Subcooling or
Hot Gas Reheat Modes.
CV valve open or leaking.
See CV Valve Operation, above.
Low Sensible Capacity in Normal Cool
or Subcooling Reheat Modes.
RH2 valve open or leaking.
See RH2 Valve Operation, above.
Low Suction Pressure and High
Superheat During Normal Cool Mode.
General cooling mode problem.
See Cooling Service Analysis (Table 14).
RH2 valve open or leaking.
See RH2 Valve Operation, above.
Low Suction Pressure
and High Discharge Pressure.
General cooling mode problem.
See Cooling Service Analysis (Table 14).
Both RH1 and CV valves closed.
See RH1 and CV Valve Operation, above.
RH2 Valve Cycling On/Off.
Hot Gas Reheat mode low suction pressure limit.
Normal Operation During Mixed Circuit Subcooling and Hot Gas Reheat
Modes at Lower Outdoor Temperatures.
Circuit B or C Will Not Operate With
Circuit A Off.
Normal operation. Motormaster outdoor fan con-
trol requires operation of circuit A.
None
LEGEND
CRC
--- Cooling/Reheat Control
CV
--- Cooling Valve
RH
--- Relative Humidity
48/
50P
G
and
P
M
Summary of Contents for 48/50PG Series
Page 32: ...32 C07009 Fig 20 Air Baffle Dimensions 48 50PG03 16 48 50PG and PM...
Page 33: ...33 C08077 Fig 21 Air Baffle Dimensions 48 50PG20 28 and 48 50PM16 28 48 50PG and PM...
Page 58: ...58 C08549 Fig 28 48PG03 16 Control Wiring Schematic 48 50PG and PM...
Page 59: ...59 C08550 Fig 29 50PG03 16 Control Wiring Schematic 48 50PG and PM...
Page 64: ...64 C08471 Fig 34 Typical 48PG and PM16 28 Control Schematic 48PM16 28 Shown 48 50PG and PM...
Page 66: ...66 C08557 Fig 36 Typical 50PG and PM16 28 Control Schematic 50PG20 28 Shown 48 50PG and PM...
Page 68: ...68 C08558 Fig 38 Typical 48 50PG and PM16 28 Power Schematic 48 50PM16 28 Shown 48 50PG and PM...
Page 72: ...72 C08565 Fig 42 Typical 48 50PG20 28 Component Arrangement 48 50PG20 24 Shown 48 50PG and PM...
Page 73: ...73 C08067 Fig 43 48 50PM16 28 Component Arrangement 48 50PG and PM...
Page 74: ...74 C08562 Fig 44 48 50PM16 28 with Humidi MiZert Component Arrangement 48 50PG and PM...
Page 208: ...208 48 50PG and PM...