GVZC20 Service Manual
SERVICING
15
The required wires are data lines 1 and 2.
The thermostat needs 4 wires between the indoor unit and
thermostat or 5 wires if the thermostat requires a Common
wire.
NOTE:
Regarding the wiring of the indoor unit to the thermostat,
also refer to ComfortBridge compatible indoor unit’s Install
manual (in case of communicating inverter system.).
If Installing with a CTK04 thermostat, please see the
addendum for further instructions.”
1
2 R
C
ComfortBridge
TM
Compable
Air Handler Blower,
Gas Furnace or Module Blower
Integrated Control Module
(*) Allowable Maximum Length
Outdoor unit
Integrated Control Module
250 . (*)
1
2 R
C
SYSTEM WIRING
G
W Y
DH
Y2
R
C
Single-Stage Thermostat(24 VAC )
G
W Y
De-
hum
R
C
:Oponal Wiring
HIGH VOLTAGE !
DISCONNECT ALL POWER BEFORE SERVICING OR
INSTALLING. MULTIPLE POWER SOURCES MAY BE
PRESENT. FAILURE TO DO SO MAY CAUSE PROPERTY
DAMAGE, PERSONAL INJURY OR DEATH.
A step-down transformer (208/230 volt primary to 24 volt
secondary) is provided with each indoor unit. This al-
lows ample capacity for use with resistance heaters. The
outdoor sections do not contain a transformer (see note
below). (see indoor unit WIRING DIAGRAM)
DISCONNECT ALL POWER BEFORE SERVICING.
1. Remove control panel cover, or etc., to gain access to
transformer.
With power ON:
L
INE
V
OLTAGE
NOW
PRESENT
.
2. Using a voltmeter, check voltage across secondary volt-
age side of transformer (R to C).
3. No voltage indicates faulty transformer, bad wiring, or
bad splices.
4. Check transformer primary voltage at incoming line
voltage connections and/or splices.
5. If line voltage available at primary voltage side of
transformer and wiring and splices good, transformer is
inoperative. Replace.
HIGH VOLTAGE !
DISCONNECT ALL POWER BEFORE
SERVICING OR
INSTALLING. MULTIPLE POWER SOURCES MAY BE
PRESENT. FAILURE TO DO SO MAY CAUSE PROPERTY
DAMAGE, PERSONAL INJURY OR DEATH.
The high pressure switch senses the pressure in the com-
pressor discharge line. If abnormally high condensing pres-
sures develop, the contacts of the control open, breaking
the control circuit before the compressor motor overloads.
This control is automatically reset.
1. Using an ohmmeter, check across the X32A connection
on outdoor unit PCB high pressure control, with wire
removed. If not continuous, the contacts are open.
2. Attach a gauge to the dill valve port on the base valve.
With power ON:
L
INE
V
OLTAGE
NOW
PRESENT
.
3. Start the system in charge mode and place a piece of
cardboard in front of the outdoor coil, raising the con-
densing pressure.
4. Check pressure at which the high pressure control cuts-
out. If it cuts-out at 605 PSIG to -17 PSIG, it is operating
normally (See causes for high head pressure in Service
Problem Analysis Guide). If it cuts out below this pres-
sure range, replace the control.
The HI/LOW pressure sensor senses the suction pressure
in cooling mode, and the discharge pressure in heating
mode. Follow the following sequence to check the pressure
sensor.
1. Connect manifold gauge to the air conditioner unit
2. Connect a pair of extended Molex probe tips to your
voltmeter test leads.
3. Find the suction pressure in the cool mode, or discharge
pressure in the heat mode (terminals) Locate (X17A)
connection and connect a DC voltmeter across sensor
terminals 1 and 3, (black and white wires) and record the
DC voltage.