GSZH5 Service Manual
69
SERVICING
1. Remove outer case, control panel cover, etc., from unit
being tested.
With power ON:
WARNING
2. Using a voltmeter, measure the voltage across
terminals L1 and L2 of the contactor for the condensing
heaters.
3. No reading - indicates open wiring, open fuse(s) no
power or etc., from unit to fused disconnect service.
Repair as needed.
4. With ample voltage at line voltage connectors, energize
the unit.
5. Measure the voltage with the unit starting and
operating, and determine the unit Locked Rotor
Voltage.
are energized.
is the actual voltage available at
the compressor during starting, locked rotor, or a stalled
condition. Measured voltage should be above minimum
listed in chart below.
To measure Locked Rotor Voltage attach a voltmeter to the
run "R" and common "C" terminals of the compressor, or to
the T1 and T2 terminals of the contactor. Start the unit and
allow the compressor to run for several seconds, then shut
down the unit. Immediately attempt to restart the unit while
measuring the Locked Rotor Voltage.
6. Locked rotor voltage should read within the voltage
tabulation as shown. If the voltage falls below the
minimum voltage, check the line wire size. Long runs of
undersized wire can cause low voltage. If wire size is
adequate, notify the local power company in regard to
either low or high voltage.
Unit Supply Voltage
Voltage Min. Max
208/230
197 253
460 414
506
section on electric heaters to calculate temperature
heating.
WARNING
1. Check wiring visually for signs of overheating,
damaged insulation and loose connections.
2. Use an ohmmeter to check continuity of any suspected
open wires.
3. If any wires must be replaced, replace with comparable
gauge and insulation thickness.
Thermostat Wiring: The maximum wire length for 18 AWG
thermostat wire is 100 feet.
Thermostat Wiring
WARNING
With power ON, thermostat calling for cooling
1. Use a voltmeter to check for 24 volts at thermostat
wires C and Y in the condensing unit control panel.
2. No voltage indicates trouble in the thermostat, wiring or
external transformer source.
3. Check the continuity of the thermostat and wiring.
Repair or replace as necessary.
Indoor Blower Motor
With power ON:
WARNING
1. Set fan selector switch at thermostat to “ON” position.
2. With voltmeter, check for 24 volts at wires C and G.
3. No voltage indicates the trouble is in the thermostat or
wiring.
4. Check the continuity of the thermostat and wiring.
Repair or replace as necessary.