Maytag Amana PMH Series Service And Troubleshooting page 32

SERVICING
B. Dry bulb temperature of air leaving conditioner. Ther-
mometer has to be located as illustrated.
C. The dry bulb thermometer temperature on the sling
psychrometer should be plus or minus 1°F within read-
ing obtained on thermometer in the return air. Check
wet bulb temperature on sling psychrometer and record
same.
D. After the wet bulb temperature, dry bulb temperature,
and return air temperature have been recorded, proceed
to calculate the temperature difference as follows.
E. Subtract temperature obtained in Step B from tempera-
ture obtained in Step A. The remainder temperature is
used to calculate from the Cooling Range Chart.
EXAMPLE: Assume a PTH15 unit is under test and the
temperature readings indicated below were obtained.
1. Return air D.B. temperature: 80°F, Step A.
2. Discharge air D.B. temperature: 69°F, Step B.
3. Return air, wet and dry bulb temperature as recorded in
Step C: Dry Bulb 80°F, Wet Bulb 75°F.
4. In left hand column of Cooling Capacity Charge headed
Dry Bulb, find the 80° value.
5. In column headed Wet Bulb find the 75°F value and find
the value 8 -13 in the cooling range column under the
Model "PTH153 PTH154".
This data shows that the temperature of the air passing
through the cooling coil is reduced at least 8°F but not
more than 13°F. This example unit is operating normally
for the existing conditions.
For the example unit under test, the temperature difference
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 addition-
al 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 discharge 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 column
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.
Proceed as follows and observe test readings as simulta-
neously 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
temperature (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 appli-
cable 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
electric 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 de-
scribed 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.
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