SCHEDULED MAINTENANCE
29
Package gas units require 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
contract, which places all maintenance in the hands of a
trained serviceman, should be pointed out to the owner.
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.
ONCE A MONTH
1. Inspect the return filters of the evaporator unit and clean
or change if necessary.
NOTE:
Depending on operation
conditions, 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 con-
densate 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
oiling. 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 connec-
tions, 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
positioning.
9. Start the system, using the proper instrumentation check
gas inlet and manifold pressures, burner flame and
microamp 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 essen-
tial 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
windings 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 - mea-
sure proper refrigerant charge.
9. Inclined Manometer - measure static pressure and
pressure 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 Problem 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 contacting your local utility.)