Goodman [A/G]PG, Service Instructions Manual

Page: 22 / 52

22
SCHEDULED MAINTENANCE
Package gas units requires regularly scheduled maintenance
to preserve high performance standards, prolong the service
life of the equipment, and lessen the chances of costly failure.
In many instances the owner may be able to perform some of
the maintenance; however, the advantage of a service con-
tract, which places all maintenance in the hands of a trained
serviceman, should be pointed out to the owner.
ONCE A MONTH
1. Inspect the return filters of the evaporator unit and clean or
change if necessary. NOTE: Depending on operation con-
ditions, it may be necessary to clean or replace the filters
more often. If permanent type filters are used, they should
be washed with warm water and dried.
2. When operating on the cooling cycle, inspect the conden-
sate line piping from the evaporator coil. Make sure the
piping is clear for proper condensate flow.
ONCE A YEAR
Qualified Service Personnel Only
1. Clean the indoor and outdoor coils.
2. Clean the cabinet inside and out .
3. Motors are permanently lubricated and do not require oil-
ing. TO AVOID PREMATURE MOTOR FAILURE, DO NOT
OIL.
4. Manually rotate the outdoor fan and indoor blower to be
sure they run freely.
5. Inspect the control panel wiring, compressor connections,
and all other component wiring to be sure all connections
are tight. Inspect wire insulation to be certain that it is
good.
6. Check the contacts of the compressor contactor. If they
are burned or pitted, replace the contactor.
7. Using a halide or electronic leak detector, check all piping
and etc. for refrigerant leaks.
8. Check the combustion chamber (Heat Exchanger) for soot,
scale, etc. Inspect all burners for lint and proper position-
ing.
9. Start the system, using the proper instrumentation check
gas inlet and manifold pressures, burner flame and micro-
amp signal. Adjust if necessary.
10. Start the system and run a Heating Performance Test. If
the results of the test are not satisfactory, see the "Service
Problem Analysis" Guide for the possible cause.
TEST EQUIPMENT
Proper test equipment for accurate diagnosis is as essential
as regular hand tools.
The following is a must for every service technician and service
shop:
1. Thermocouple type temperature meter - measure dry bulb
temperature.
2. Sling psychrometer- measure relative humidity and wet bulb
temperature.
3. Amprobe - measure current.
4. Volt-Ohm Meter - testing continuity, capacitors, motor wind-
ings and voltage.
5. Accurate Leak Detector - testing for refrigerant leaks.
6. High Vacuum Pump - evacuation.
7. Electric Vacuum Gauge, Manifold Gauges and high vacuum
hoses - to measure and obtain proper vacuum.
8. Accurate Charging Cylinder or Electronic Scale - measure
proper refrigerant charge.
9. Inclined Manometer - measure static pressure and pres-
sure drop across coils.
Other recording type instruments can be essential in solving
abnormal problems, however, in many instances they may be
rented from local sources.
Proper equipment promotes faster, more efficient service, and
accurate repairs with less call backs.
HEATING PERFORMANCE TEST
Before attempting to diagnose an operating fault, run a Heating
Performance Test and apply the results to the Service Prob-
lem Analysis Guide.
To conduct a heating performance test, the BTU input to the
package gas unit must be calculated.
After the heating cycle has been in operation for at least fifteen
minutes and with all other gas appliances turned off, the gas
meter should be clocked.
To find the BTU input, multiply the number of cubic feet of gas
consumed per hour by the heating value of the gas being used.
(The calorific value of the gas being used is found by contact-
ing your local utility.)