Checking Temperature Rise; Checking Primary Limit Control - Goodman Amana AMH8 Service Instructions Manual

SERVICING
4. Consult proper tables for the quantity of air.
If the total external static pressure exceeds the mini-
mum or maximum allowable statics, check for closed
dampers, registers, undersized and/or oversized poorly
laid out duct work.
SUPPLY
AIR
CUTAWAY OF DUCTWORK
Amana
Elec tronic Ai r Cleaner
Ca ution
High Voltage
To a void per sonal in j u ry, wait 15
secon ds afte r de -ene rgizing u nit
b efore touch i n g unit i n terior .
Checking Static Pressure
(80% Furnace Shown, 90% Similar)
S-201 CHECKING TEMPERATURE RISE
The more air (CFM) being delivered through a given fur-
nace, the less the rise will be; so the less air (CFM)
being delivered, the greater the rise. The temperature
rise should be adjusted in accordance to a given fur-
nace specifications and its external static pressure. An
incorrect temperature rise may result in condensing in
or overheating of the heat exchanger. An airflow and
temperature rise table is provided in the blower per-
formance specification section. Determine and adjust
temperature rise as follows:
1. Operate furnace with burners firing for approxi-
mately ten minutes. Check BTU input to furnace -
do not exceed input rating stamped on rating plate.
Ensure all registers are open and all duct dampers
are in their final (fully or partially open) position.
2. Place thermometers in the return and supply ducts
as close to the furnace as possible. Thermometers
must not be influenced by radiant heat by being able
to "see" the heat exchanger.
TO EXPOSE COIL
INCLINED
MANOMETER
RETURN
AIR

Checking Temperature Rise

3. Subtract the return air temperature from the sup-
ply air temperature to determine the air tempera-
ture rise. Allow adequate time for thermometer
readings to stabilize.
4. Adjust temperature rise by adjusting the circula-
tor blower speed. Increase blower speed to reduce
temperature rise. Decrease blower speed to in-
crease temperature rise. Refer to Circulator Blower
Speed section in the Product Design section of this
manual for speed changing details. Temperature rise
is related to the BTUH output of the furnace and
the amount of air (CFM) circulated over the heat
exchanger. Measure motor current draw to deter-
mine that the motor is not overloaded during ad-
justments.
S-300 CHECKING PRIMARY LIMIT CONTROL
All use a nonadjustable, automatic reset, bi-metal type
limit control. Refer to the following drawing for the
location of the primary limit.
SUPPLY
AIR
RETURN
AIR
53