Goodman ACES80 Series, Service And Troubleshooting

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SCHEDULED MAINTENANCE
26
BURNERS
WARNING
HIGH VOLTAGE
E
LECT R ICAL COMPONENT S A R E CONTAINED IN BOTH
COMPA R TMENT S .
T
O AVOID ELECT R ICAL S HOC K , IN J U R Y O R
DEATH, DO NOT R EMOVE ANY INTE R NAL COMPA R TMENT COVE RS
O R ATTEMPT ANY AD J U S TMENT.
C
ONTACT A Q UALIFIED
S E R VICE AGENT AT ONCE IF AN ABNO R MAL FLAME
APPEA R ANCE S HOULD DEVELOP.
Periodically during the heating season make a visual check of
the burner flames. Turn the furnace on at the thermostat. Wait
a few minutes since any dislodged dust will alter the normal
flame appearance. Flames should be stable, quiet, soft and
blue with slightly orange tips. They should not be yellow. They
should extend directly outward from the burner ports without
curling downward, floating or lifting off the ports.
Check the burner flames for:
1. Stable, soft and blue
2. Not curling, floating, or lifting off.
Burner Flame
TEST EQUIPMENT
Proper test equipment for accurate diagnosis is as essential
as regular hand tools.
The following is a must for every service technician and
service shop.
1. Dial type thermometers or thermocouple meter (option-
al) - to measure dry bulb temperature.
2. Amprobe - to measure amperage and voltage.
3. Volt-Ohm Meter - testing continuity, capacitors, and
motor windings.
4. Inclined Manometer - to measure static pressure, pres-
sure drop across coils, filters, and draft.
5. Water Manometer (12”) - to test gas inlet and manifold
pressure.
Other recording type instruments can be essential in solving
abnormal problems, however, in many instances they may
be rented from local sources.
Proper equipment promotes faster, more efficient service and
accurate repairs resulting in fewer call backs.
HEATING PERFORMANCE TEST
Before attempting to diagnose an operating fault, run a heating
performance test and apply the results to the
Service Problem
Analysis Guide.
To conduct a heating performance test, the BTU input to the
furnace must be calculated.
After the heating cycle has been in operation for at least fifteen
minutes and with all other gas appliances turned off, the gas
meter should be clocked.
To find the BTU input, multiply the number of cubic feet of
gas consumed per hour by the heating value of the gas being
used. (The calorific value of the gas being used is found by
contacting your local utility.)
EXAMPLE: It is found by the gas meter, that it takes forty
(40) seconds for the hand on the cubic foot dial to make
one complete revolution, with all appliances off, except the
furnace. Take this information and locate it on the gas rate
chart. Observe the forty (40) seconds, locate and read across
to the one (1) cubic foot dial column. There we find the number
90, which shows that ninety (90) cubic feet of gas will be
consumed in one (1) hour.
Let’s assume the local gas utility has stated that the calorific
value of the gas is 1,025 BTU per cubic foot.
Multiplying the ninety (90) cubic feet by 1,025 BTU per cubic
foot gives us an input of 92,250 BTUH.
Checking the BTU input on the rating plate of the furnace
being tested.
EXAMPLE:
INPUT: 92,000 BTU/HR
OUTPUT CAP: 84,000
Should the figure you calculated not fall within five (5) percent
of the nameplate rating of the unit, adjust the gas valve
pressure regulator or resize orifices.
A
LWAY S CONNECT A MONOMETE R TO THE OUTLET TAP AT THE GA S
VALVE BEFO R E AD J U S TING THE P R E SS U R E R EGULATO R .
I
N NO CA S E
S HOULD THE FINAL MANIFOLD P R E SS U R E VA R Y MO R E THAN PLU S O R
MINU S . 3 INCHE S WATE R COLUMN F R OM 3 .5 INCHE S WATE R COLUMN
FO R NATU R AL GA S O R 10 INCHE S WATE R COLUMN FO R P R OPANE GA S .
CAUTION
To adjust the pressure regulator on the gas valve, turn
down (clockwise) to increase pressure and input, and out
(counterclockwise) to decrease pressure and input.
Since normally propane gas is not installed with a gas meter,
clocking will be virtually impossible. The gas orifices used
with propane are calculated for 2500 BTU per cubic foot gas
and with proper inlet pressures and correct piping size, full
capacity will be obtained.
With propane gas, no unit gas valve regulator is used;
however, the second stage supply line pressure regulator
should be adjusted to give 11” water column with all other
gas consuming appliances running.
The dissipation of the heat transferred to the heat exchanger is
now controlled by the amount of air circulated over its surface.
The amount (CFM) of air circulated is governed by the external
static pressure in inches of water column of duct work, cooling
coil, registers, etc., applied externally to the unit versus the
motor speed tap (direct drive) or pulley adjustments of the
motor and blower (belt drive).
A properly operating unit must have the BTU per hour input
and CFM of air, within the limits shown to prevent short cycling
of the equipment. As the external static pressure goes up, the
temperature rise will also increase. Consult the proper tables
for temperature rise limitation.