Carrier 50PG20-28 Controls, Start-Up, Operation, Service And Troubleshooting Instructions page 60

Table 46 -- Economizer Service Analysis
PROBLEM
Damper Does Not Move.
POSSIBLE CAUSE
Indoor Fan is off.
Economizer Operation is Limited
to Minimum Position,
Economizer Position is Less
Than Minimum Position.
Economizer Does Not Return
to Minimum Position,
Damper Does Not Close on
Power Loss,
Outdoor Damper Does Not Fully
Close at 0% or Fully Open at 100%,
LEGEND
CCN -- Carrier Comfort Network®
IAQ -- Indoor Air Quality
Actuator is unplugged at motor or at
economizer board.
Unit is not configured for economizer.
Outdoor-air temperature is above economizer
high temperature lockout.
Outdoor-air temperature is below economizer
low temperature lockout.
Communication loss to economizer board.
Damper is jammed.
Minimum position is set incorrectly.
Outdoor-air temperature is above economizer
high temperature lockout.
Outdoor-air temperature is below economizer
low temperature lockout.
Outdoor-air thermistor is faulty.
Low suction pressure problem with a compressor.
IAQ is controlling minimum damper position.
Unit is in Unoccupied mode.
Unit is operating under free cooling.
Damper is jammed.
Economizer actuator is out of calibration.
REMEDY
Check for proper thermostat connection.
Unit is not configured for continuous fan
operation and the thermostat is not calling for
heating or cooling.
Unit is in Unoccupied mode and there is no
call for heating or cooling.
Tripped circuit breaker.
No power to the unit.
Unit is offvia CCN command.
Check wiring connections.
Configure unit for economizer per the
instructions.
Adjust the high temperature lockout setting
if it is incorrect, otherwise, economizer is
operating correctly.
Adjust the low temperature lockout setting
if it is incorrect, otherwise, economizer is
operating correctly.
Check wiring connections.
Identify the obstruction and safely remove.
Adjust minimum position setting.
Adjust the high temperature lockout setting
if it is incorrect, otherwise, economizer is
operating correctly.
Adjust the low temperature lockout setting
if it is incorrect, otherwise, economizer is
operating correctly.
Replace outdoor-air thermistor.
Economizer is operating correctly, identify
compressor problem.
Adjust the IAQ settings if incorrect,
otherwise, the economizer is operating correctly.
Adjust unit occupied schedule if incorrect,
otherwise, economizer is operating correctly.
Economizer is operating correctly.
Identify the obstruction and safely remove.
Enter Service Test mode and run the Calibrate
Economizer (E.CAL) procedure.
Heating Troubleshooting- Use the unit Scrolling
Marquee display or a CCN device to view the heating status
display and the heating diagnostic display (see Appendix A)
for information on the heating operation. Check the current
alarms and alarm history tbr any heating alarm codes and
correct any causes (see Table 44). Verit) any unique control
confignrations per installed site requirements or accessories. If
alarms conditions are corrected and cleared, operation of the
heat stages and indoor tan may be verified by using the Service
Test mode (see page 36 and Table 36).
GAS HEAT (48PG UNITS) See Table 47 for general gas
heating service analysis. See Fig. 12 lbr service analysis of the
IGC board logic. Check the status LED on the IGC board for
any tlashing alarm codes and correct any causes (see Table 48).
ELECTRIC HEAT (50PG UNITS) See Table 49 for elec-
tric heating service analysis.
Phase Loss Protection -- The phase loss protection
option will monitor the three-phase electzical system to provide
phase reversal and phase loss protection.
PHASE REVERSAL PROTECTION If the control sens-
es an incorrect phase relationship, the relay (K1) will be de-
energized (opening its contact). If the phase relationship is
correct, the relay will be eneNized. The control has a self-
bypass function after a pre-set time. If the control determines
that the three phases stay in a correct relationship for 10 con-
secutive minutes, the relay will stay energized regardless of the
phase sequence of three inputs as long as 24-vac control
voltage is applied. This self-bypass function will be reset if all
three phases are restored in a phase loss event.
PHASE LOSS PROTECTION If the reverse rotation
board senses any one of the three phase inputs has no AC volt-
age, the relay will be deenergized (opening its contact). This
protection is always active as long as 24-vac control voltage is
applied, and is not affected by the self by-pass function of the
phase sequence monitoring function. However, in the event of
phase loss, the relay wilt be re-eneigized only ifalt three phases
are restored and the three phases are in the correct sequence.
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