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16
Table 3 – Humidi
−
MiZer
R
Troubleshooting
PROBLEM
CAUSE
REMEDY
Subcooling Reheat Mode Will
Not Activate
General cooling mode problem
See Cooling Service Troubleshooting (Table 4).
No dehumidification demand
See No Dehumidification Demand, below.
CRC relay operation
See CRC Relay Operation, below.
Circuit RLV, CLV or LDV valve problem
See CLV, RLV or LDV Valve Operation, below.
Hot Gas Reheat Mode Will Not
Activate
General cooling mode problem
See Cooling Service Troubleshooting (Table 4).
No dehumidification demand
See No Dehumidification Demand, below.
CRC relay operation
See CRC Relay Operation, below.
Circuit RLV, CLV or LDV valve problem
See CLV, RLV or LDV Valve Operation, below.
Circuit RDV valve is not open
See RDV Valve Operation, below.
Outdoor temperature too low
Check Reheat 2 Circuit Limit Temperatures (Configuration
→
HMZR
→
RA.LO and RB.LO) using
Comfort
Link Scrolling Marquee.
No Dehumidification Demand
Relative humidity setpoint too low — Humidistat
Check/reduce setting on accessory humidistat.
Relative humidity setpoint too low — RH sensor
Check Space RH Setpoints (Setpoints
→
RH.SP and RH.UN) and
occupancy using ComfortLink Scrolling Marquee.
Software configuration error for accessory
humidistat
Check Space Humidity Switch (Configuration UNIT RH.SW) using
ComfortLink Scrolling Marquee.
Software configuration error for accessory
humidity sensor
C
h
eck RH Sensor on OAQ Input (Configuration
→
UNIT
→
RH.S)
using ComfortLink 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 ComfortLink 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.
RLV, CLV or LDV Valve Operation
No 24V signal to input terminals
Check using Cool
→
Reheat1 Valve Test (Service Test
→
HMZR
→
CRC) using ComfortLink 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.
RDV 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 ComfortLink 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 Subcool
ing or Hot Gas Reheat Modes
CLV valve open or leaking
See CLV Valve Operation, above.
Low Sensible Capacity in Normal
Cool or Subcooling Reheat
Modes
RDV valve open or leaking
See RDV Valve Operation, above.
Low Suction Pressure and High
Superheat During Normal Cool
Mode
General cooling mode problem
See Cooling Service Troubleshooting (Table 4).
RDV valve open or leaking
See RDV Valve Operation, above.
Low Suction Pressure and High
Discharge Pressure
General cooling mode problem
See Cooling Service Troubleshooting (Table 4).
Both RLV and CLV valves closed
See RLV and CLV Valve Operation, above.
RDV 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 Will Not Operate With
Circuit A Off
Normal operation. Motormaster outdoor fan
control requires operation of circuit A.
None
LEGEND
CRC —
Cooling/Reheat Control
CLV —
Cooling Liquid Valve
RLV —
Reheat Liquid Valve
RH —
Relative Humidity
RDV —
Reheat Discharge Valve
Summary of Contents for 48TC 17 Series
Page 39: ...39 C10818 Fig 45 RTU OPEN Control Module ...
Page 83: ...83 APPENDIX IV WIRING DIAGRAMS cont C12616 Fig 74 48TC D17 D28 Power Diagram 208 230 3 60 ...
Page 84: ...84 APPENDIX IV WIRING DIAGRAMS cont C12266 Fig 75 48TC D17 D28 Power Diagram 460 3 60 ...
Page 85: ...85 APPENDIX IV WIRING DIAGRAMS cont C12618 Fig 76 48TC D17 D28 Power Diagram 575 3 60 ...
Page 92: ...92 APPENDIX IV WIRING DIAGRAMS cont C13767 Fig 83 RTU OPEN Wiring Diagram ...
Page 93: ...93 APPENDIX IV WIRING DIAGRAMS cont C13768 Fig 84 RTU OPEN Wiring Diagram with Humidi MiZer ...