GVZC20 Service Manual
SERVICING
39
TROUBLESHOOTING-INDOOR UNIT FOR EEV APPLICABLE UNIT
HIGH VOLTAGE !
DISCONNECT ALL POWER BEFORE SERVICING.
M
ULTIPLE POWER SOURCES MAY BE PRESENT. FAILURE
TO DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL
INJURY OR DEATH.
INDOOR UNIT CONTROL BOARD
AUXILIARY ALARM SWITCH
The control is equipped with two Auxiliary Alarm terminals,
labeled TB4 and TB5, which are typically utilized in series
with a condensate switch but could also be used with com-
patible CO2 sensors or re alarms.
The auxiliary alarm switch must be normally closed and
open when the alarm occurs. For example, a normally
closed condensate switch will open when the base pan’s
water level reaches a particular level. The control will
respond by turning o the blower motor and displaying the
proper fault codes. If the switch is later detected closed
for 30 seconds, normal operation resumes and the error
message is removed. The switch is closed as part of the
default factory setting. The error will be maintained in the
equipment’s fault history.
CIRCULATOR BLOWER
This air handler is equipped with a variable speed circulator
blower. This blower provides several automatically-adjusted
blower speeds. The Specication Sheet applicable to your
model provides an airow table, showing the relationship
between airow (CFM) and external static pressure (E.S.P.).