SERVICING
49
WARNING
HIGH
VOLTAGE
D
ISCONNECT
ALL
POWER BEFORE SERVICING OR
INSTALLING THIS UNIT.
M
ULTIPLE POWER SOURCES MAY
BE PRESENT.
F
AILURE TO DO SO MAY CAUSE PROPERTY
DAMAGE, PERSONAL INJURY OR DEATH.
1. Remove blower compartment door to gain access to
capacitor.
2. Discharge capacitor and remove wire leads.
3. Set an ohmmeter on its highest ohm scale and connect
the leads to the capacitor.
a.
Good Condition - indicator swings to zero and
slowly returns toward infinity.
b.
Shorted - indicator swings to zero and stops there
- replace.
c.
Open - no reading - replace. Reverse leads.
Check again no reading - replace.
d.
Reverse leads and recheck.
S-16 CHECKING AIR CIRCULATOR BLOWER MO-
TOR (PSC)
D
ISCONNECT
ALL
POWER BEFORE SERVICING.
WARNING
1. Remove blower compartment door to gain access to the
circulator blower motor and integrated ignition control.
2. Discharge the capacitor on (PSC) motors. Disconnect
the motor wire leads from its connection point at the
integrated ignition control module and capacitor if ap-
plicable.
3. Using a ohmmeter, test for continuity between each of
the motor leads.
4. Touch one probe of the ohmmeter to the motor frame
(ground) and the other probe in turn to each lead.
If the windings do not test continuous or a reading is ob-
tained to ground, replace the motor.
5. After completing check and/or replacement of circulator
blower motor or induced draft blower motor, reinstall
blower compartment door.
6. Turn on electrical power and verify proper unit operation.
D
ISCONNECT
ALL
POWER BEFORE SERVICING.
WARNING
S-200 CHECKING DUCT STATIC
The maximum and minimum allowable external static pres-
sures are found in the specification section. These tables
also show the amount of air being delivered at a given static
by a given motor speed or pulley adjustment.
The furnace motor cannot deliver proper air quantities (CFM)
against statics other than those listed.
Too great of an external static pressure will result in insuffi-
cient air that can cause excessive temperature rise, result-
ing in limit tripping, etc. Whereas not enough static may
result in motor overloading.
To determine proper air movement, proceed as follows:
1. With clean filters in the furnace, use a draft gauge
(inclined manometer) to measure the static pressure of
the return duct at the inlet of the furnace. (Negative
Pressure)
2. Measure the static pressure of the supply duct. (Posi-
tive Pressure)
3. Add the two (2) readings together for total external static
pressure.
NOTE:
Both readings may be taken simultaneously and
read directly on the manometer if so desired. If an air
conditioner coil or Electronic Air Cleaner is used in con-
junction with the furnace, the readings must also include
theses components, as shown in the following drawing.
4. Consult proper tables for the quantity of air.
If the total external static pressure exceeds the minimum or
maximum allowable statics, check for closed dampers, reg-
isters, undersized and/or oversized poorly laid out duct
work.
Amana
Ele c tr o nic Ai r Cle a n er
Ca ution
High Voltage
To a void per sonal in ju ry, wait 15
secon ds afte r de -ene rgizing u nit
b efore touch in g unit in terior .
CUTAWAY OF DUCTWORK
TO EXPOSE COIL
SUPPLY
AIR
INCLINED
MANOMETER
RETURN
AIR
Checking Static Pressure
(80% Furnace Shown, 90% Similar)
