System Balance; Maintaining Unit In Good Working Order; Refrigerant Charges - Johnson Controls VPC Installation, Operation & Maintenance Instructions Manual

23. SYSTEM BALANCE

Electric heating elements require a mini-
mum airflow to ensure proper heating
output and maximum element operating
life. Low airflow will also cause poor
cooling performance.
Blower speed taps are factory set for optimum heating
and cooling airflow ranges. Refer to Table 1 for factory
blower speed settings, and minimum allowable heating
airflow.
Operating unit below the minimum
heating airflow may cause poor heating
performance and decreased resistant
heater life.
Installed system must be test run to ensure operation
with sufficient heating and cooling airflow. Duct work
static pressure should not exceed 0.3 inches W.C. in
order to ensure proper volume of air flow.
24. MAINTAINING YOUR UNIT IN GOOD WORKING
ORDER
Follow these procedures before inspect-
ing unit.
• Turn room thermostat to the 'OFF' system set-
ting.
• Wait at least five minutes for unit to cool if it was
recently operating.
• Turn off unit electrical power; failure to do so could
result in injury or death.
Use only recommended replacements
parts. Failure to do so could cause im-
proper unit operation, resulting in dam-
age, injury or death.
JOHNSON CONTROLS
Perform periodic preventive maintenance once before
heating season begins and once before cooling sea-
son. Inspect, clean and repair as needed the following
items:
1) all electrical wiring and connections, including
electrical ground.
2) all supply air and return air ducts for obstructions,
air leaks and loose insulation.
3) Blower housings, motors and wheels, and air
filters. Blower motors do not require oiling.
4) Inspect indoor and outdoor coils for accumulations
of dirt and debris, and clean as required. If the coils
appear dirty, clean them using mild detergent or a
commercial coil cleaning agent.
Dirty or clogged indoor coils cause low suction
pressures and lost cooling capacity.
When operating in Cooling, with a clean outdoor
coil, the air temperature leaving the outdoor fan
discharge should be approximately 33ºF above the
outdoor air temperature. The saturated condensing
temperature should be approximately 38ºF above
the outdoor air temperature.
Outdoor
o
Temp F
70
75
80
85
90
95
If the condensing pressure is higher than shown in the
table above, dirt in the condenser must be suspected.
To clean the condenser coil, remove the wall grille from
the outside and remove the accumulated dirt from the
air intake face of the coil using a brush and/or vacuum
cleaner. always remove all dislodged dirt from inside
the wall sleeve so that it will not be sucked back into
the condenser coil.

25. REFRIGERANT CHARGES

UNIT MODEL#
vP***0912
vP***1212
vP***1812
vP***2412
FORM 145.20-IOM1 (908)
Condensing
Pressure (psig)
200
215
230
245
260
280
R-22 CHARGE
2 lb.- 6 oz.
2 lb.-10 oz.
3 lb.-11 oz.
4 lb.-10 oz.
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