Service manual

SERVICING
30
Model Switch 5 Switch 6 CFM
OFF
OFF
1,200
ON
OFF
1,000
OFF
ON
800
ON
ON
600
OFF
OFF
1,600
ON
OFF
1,400
OFF
ON
1,200
ON
ON
1,000
OFF
OFF
1,600
ON
OFF
1,400
OFF
ON
1,200
ON
ON
1,000
OFF
OFF
1,100
ON
OFF
800
OFF
ON
600
OFF
OFF
1,800
ON
OFF
1,580
OFF
ON
1,480
ON
ON
1,200
Cooling/Heat Pump Operation
AEPT36/60
MBE2000
AEPT30
MBE1200
MBE1600
Table 3
THERMOSTAT “FAN ONLY” MODE
During Fan Only Operations, the CFM output is 30% of the
cooling setting.
CFM TRIM ADJUST
Minor adjustments can be made through the dip switch
combination of 7-8. Table 4 shows the switch position for this
feature.
NOTE: The airflow will not make the decreasing adjustment
in Electric Heat mode.
CFM Switch 7 Switch 8
+10% ON OFF
-15% OFF ON
Table 4
HUMIDITY CONTROL
When using a Humidstat (normally closed), cut jumper PJ6
on the control board. The Humidstat will only affect cooling
airflow by adjusting the Airflow to 85%.
TWO STAGE HEATING
When using staged electric heat, cut jumper PJ4 on the
control board.
S-17 CHECKING COMPRESSOR
WARNING
Hermetic compressor electrical terminal venting can
be dangerous. When insulating material which
supports a hermetic compressor or electrical terminal
suddenly disintegrates due to physical abuse or as a
result of an electrical short between the terminal and
the compressor housing, the terminal may be
expelled, venting the vapor and liquid contents of the
compressor housing and system.
If the compressor terminal PROTECTIVE COVER and gasket
(if required) are not properly in place and secured, there is a
remote possibility if a terminal vents, that the vaporous and
liquid discharge can be ignited, spouting flames several feet,
causing potentially severe or fatal injury to anyone in its path.
This discharge can be ignited external to the compressor if the
terminal cover is not properly in place and if the discharge
impinges on a sufficient heat source.
Ignition of the discharge can also occur at the venting terminal
or inside the compressor, if there is sufficient contaminant air
present in the system and an electrical arc occurs as the
terminal vents.
Ignition cannot occur at the venting terminal without the
presence of contaminant air, and cannot occur externally from
the venting terminal without the presence of an external
ignition source.
Therefore, proper evacuation of a hermetic system is essen-
tial at the time of manufacture and during servicing.
To reduce the possibility of external ignition, all open flame,
electrical power, and other heat sources should be extin-
guished or turned off prior to servicing a system.
If the following test indicates shorted, grounded or open
windings, see procedures S-19 for the next steps to be taken.
S-17A RESISTANCE TEST
Each compressor is equipped with an internal overload.
The line break internal overload senses both motor amperage
and winding temperature. High motor temperature or amper-
age heats the disc causing it to open, breaking the common
circuit within the compressor on single phase units.
Heat generated within the compressor shell, usually due to
recycling of the motor, high amperage or insufficient gas to
cool the motor, is slow to dissipate. Allow at least three to four
hours for it to cool and reset, then retest.
Fuse, circuit breaker, ground fault protective device, etc. has
not tripped -