High Altitude Application (Usa); Checking For Delayed Ignition; Checking Integrated Ignition Control Boards - Goodman GMEC96 Service Instructions Manual

SERVICING
*
* *
M 1
P 3
F O *
F
C 2
ON
*
* *
COIL COVER
PRESSURE SWITCH
INDUCED
DRAFT
BLOWER
Blower Pressure Switch
Negative Pressure Measurement
S-311 HIGH ALTITUDE APPLICATION (USA)
The furnace as shipped requires no change to run between
0 - 7500 feet. Do not attempt to increase the firing rate by
changing orifices or increasing the manifold pressure below
7500 feet. feet. This can causepoor combustion and equip-
ment failure. High altitude installations above 7500 feet. feet
may require both a pressure switch and an orifice change.
These changes are necessary to compensate for the natu-
ral reduction in the density of both the gasfuel and the com-
bustion air at higher altitude.
For installations above 7500 feet. feet, please refer to your
distributor for required kit(s). Contact the distributor for a
tabular listing of appropriate manufacturer's kits for propane
gas and/or high altitude installations. The indicated kits must
be used to insure safe and proper furnace operation. All
conversions must be performed by a qualified installer, or
service agency.
In some areas the gas supplier may artificially derate the
gas in an effort to compensate for the effects of altitude. If
the gas is artificially derated the appropriate orfice size must
be determined based on the BTU/ft
gas and the altitude. Refer to the National Fuel Gas Code,
NFPA 54/ANSI Z223.1, and information provided by the gas
supplier to determine the proper orifice size.
S-312 CHECKING FOR DELAYED IGNITION
Delayed ignition is a delay in lighting a combustible mix-
ture of gas and air which has accumulated in the combus-
tion chamber.
Furnace design makes this extremely unlikely unless safety
controls have been by-passed or tampered with. Never by-
pass or alter furnace controls.
If delayed ignition should occur, the following should be
checked:
1. Improper gas pressure - adjust to proper pressure (See
S-307 CHECKING GAS PRESSURE).
2. Improper burner positioning - burners should be in lo-
cating slots, level front to rear and left to right.
INDUCED DRAFT BLOWER
PRESSURE SWITCH
PRESSURE SWITCH
HOSE
OPEN TO
ATMOSPHERE
1/4" TEE
INCLINED MANOMETER
HOSE TO INDUCED
DRAFT BLOWER TAP
3 content of the derated
3. Carry over (lighter tube or cross lighter) obstructed - clean.
4. Main burner orifice(s) deformed, or out of alignment to
burner - replace.
S-313 CHECKING
CONTROL BOARDS
NOTE: Failure to earth ground the furnace, reversing the neu-
tral and hot wire connection to the line (polarity), or a high
resistance connection in the neutral line may cause the con-
trol to lockout due to failure to sense flame.
WARNING
T
O AVOID THE RISK OF ELECTRICAL SHOCK, WIRING TO THE UNIT
MUST BE PROPERLY POLARIZED AND GROUNDED.
BEFORE PERFORMING SERVICE LISTED BELOW.
The ground wire must run from the furnace all the way back
to the electrical panel. Proper grounding can be confirmed
by disconnecting the electrical power and measuring resis-
tance between the neutral (white) connection and the burner
closest to the flame sensor. Resistance should be less than
2 ohms.
The ignition control is a combination electronic and electro-
mechanical device and is not field repairable. Complete unit
must be replaced.
These tests must be completed within a given time frame
due to the operation of the ignition control.
The ignition control is capable of diagnosing many furnace
failures to help in troubleshooting. The trial for ignition period
is 4 seconds.
Goodman
® Brand and Amana® Brand Two-Stage
1. Check for 120 volts from Line 1 (Hot) to Line 2 (Neutral)
at the ignition control. No voltage, check the door switch
connections and wire harness for continuity.
2. Check for 24 volts from W to C terminal on the ignition
control. No voltage. Check transformer, room thermo-
stat, and wiring.
If you have 24 volts coming off the transformer but re-
ceive approximately 13 volts on the terminal board be-
tween (C) and (R), check for blown fuse.
3. Check 120 volt outputs on the 5 pin harness.
Pin 1 = HSI Hot
Pin 2 = Inducer High
Pin 3 = Inducer Low
Pin 4 = Inducer N
Pin 5 = HSI N
INTEGRATED IGNITION
D
ISCONNECT POWER
65