44
SERVICING
For the example unit under test, the temperature differ-
ence was 11°F (80°F, return air, minimum 69°F discharge
air). Since the value is within the listed cooling range 8 -
13, this unit is considered to be operating normally.
For Total Power Input Test (wattage) the following addi-
tional readings must be recorded after the unit under
test is interconnected with a wattmeter.
• Outdoor dry bulb temperature. Avoid direct exposure
of thermometer to sunlight or to hot condenser dis-
charge air.
• Total watts input, measured by wattmeter or calculate
by multiplying applied voltage by unit amps.
Calculating Procedure
1. Locate the outdoor temperature obtained in first col-
umn of Total Power Consumption Cooling Chart.
2. Locate in second column the return air wet bulb tem-
perature obtained in Step C.
3. The total watts input should come between minimum
and maximum values indicated for each model.
EXAMPLE:
Assume that a PTH15 is again under test. Pro-
ceed as follows and observe test readings as simultaneously
as possible.
1. Outdoor dry bulb temperature reading - 95°F.
2. Check watts input - 1510.
3. Wet bulb temperature as described in Step C - 75°F.
In column headed Outdoor Dry Bulb Temperature of the Power
Consumption Chart find the 95°F value. Read to the right
from the 95°F value and find the room wet bulb tempera-
ture (75°F).
Read to the right front the 75°F W.B. value in the PTH15
column and note the minimum and maximum wattage of
1460 - 1575.
Since the wattage reading (1510) obtained in the test is
within the prescribed range, the total power input in watts
is considered to be normal.
Electric Heat Test
For the electric heat test, the following readings must be
recorded after the unit is interconnected with a wattmeter
or by recording the total amp draw to the unit.
NOTE:
Cabinet front must be in place during this test.
• Record supply voltage to unit.
• Operate unit in highest heat setting.
• Record wattage recorded on wattmeter or total amp
draw to unit.
• Refer to heating watts/amps chart. (Whichever is ap-
plicable for voltage rating on the unit being tested.)
• The total watts or amps recorded should fall within the
minimum and maximum watts/amps listed on these
charts.
EXAMPLE:
Assume that a PTH15 230/208V with 3.5 kW elec-
tric heater is under test.
1. Supply voltage as recorded - 208volts.
2. Watts recorded -2750W or Amps recorded - 13.5 Amps.
3. Locate the readings listed on the following pages. You
will note that these readings fall within the voltage,
watts and amp draw minimum and maximum ranges
listed and therefore the unit heating performance would
be considered normal.
Heating Power Consumption Test (Heat Pump Mode Only)
For the total power consumption test, the following read-
ings must be recorded after the unit is interconnected with
a wattmeter.
• Outside coil inlet air dry bulb temperature.
• Inside coil inlet air dry bulb temperature.
• Total watts input measured by wattmeter.
Calculating procedure
1. Locate temperature obtained in Step A in first column
of Heating Wattage Chart.
2. Locate in second column the inside coil inlet D.B. tem-
perature.
3. The total watts input should come between minimum
and maximum values indicated for each model.
EXAMPLE:
Assume that a PTH15 is under test.
Proceed as follows and observe test readings as simulta-
neously as possible.
1. Outside coil inlet D.B. temperature readings as described
in Step A: 45°F.
2. Check watts input: 1370 W.
3. Inside coil inlet D.B. temperature reading as described
in Step B: 75°F.
Read to the right from the 75°F inside coil inlet D.B. value
in the column and note the minimum and maximum watt-
age of 1335 - 1470.
Since the wattage reading (1370) obtained in the test is
within the prescribed range, the total power input in watts
is considered to be normal.
See the charts on the following pages.