Pressure Switches; Flame Sensor; Troubleshooting; Electrostatic Discharge (Esd) Precautions - Goodman GMH95 Installation Instructions Manual

P S
RESSURE WITCHES
The pressure switches are normally-open (closed during opera-
tion), single-pole single-throw, negative air pressure-activated
switches. They monitor the airflow (combustion air and flue prod-
ucts) through the heat exchanger via pressure taps located on the
induced draft blower and the coil front cover. These switches guard
against insufficient airflow (combustion air and flue products)
through the heat exchanger and/or blocked condensate drain con-
ditions.
F S
LAME ENSOR
The flame sensor is a probe mounted to the burner/manifold as-
sembly which uses the principle of flame rectification to determine
the presence or absence of flame.
XVIII. TROUBLESHOOTING
E D
LECTROSTATIC ISCHARGE
NOTE: Discharge body's static electricity before touching unit. An
electrostatic discharge can adversely affect electrical components.
Use the following precautions during furnace installation and ser-
vicing to protect the integrated control module from damage. By
putting the furnace, the control, and the person at the same electro-
static potential, these steps will help avoid exposing the integrated
control module to electrostatic discharge. This procedure is appli-
cable to both installed and uninstalled (ungrounded) furnaces.
1. Disconnect all power to the furnace. Do not touch the
integrated control module or any wire connected to the control
prior to discharging your body's electrostatic charge to
ground.
2. Firmly touch a clean, unpainted, metal surface of the
furnaces near the control. Any tools held in a person's
hand during grounding will be discharged.
3. Service integrated control module or connecting wiring
following the discharge process in step 2. Use caution not
to recharge your body with static electricity; (i.e., do not move
or shuffle your feet, do not touch ungrounded objects, etc.).
If you come in contact with an ungrounded object, repeat
step 2 before touching control or wires.
4. Discharge your body to ground before removing a new
control from its container. Follow steps 1 through 3 if
installing the control on a furnace. Return any old or new
controls to their containers before touching any ungrounded
object.
D C
IAGNOSTIC HART
HIGH VOLTAGE!
T
O AVOID PERSONAL INJURY OR DEATH DUE TO
,
ELECTRICAL SHOCK DISCONNECT ELECTRICAL POWER
P
BEFORE ERFORMAING ANY SERVICE OR MAINTENANCE
Refer to the Troubleshooting Chart at the end of this manual for
assistance in determining the source of unit operational problems.
The red diagnostic LED blinks to assist in troubleshooting the unit.
The number of blinks refers to a specific fault code.
(ESD) P
RECAUTIONS
WARNING
.
F R
AULT ECALL
The ignition control is equipped with a momentary pushbutton
switch that can be used to display on the diagnostic LED the last
five faults detected by the control. The control must be in Standby
Mode (no thermostat inputs) to use the feature. Depress the
pushbutton switch for approximately 2 seconds. Release the switch
when the LED is turned off. The diagnostic LED will then display
the flash codes associated with the last five detected faults. The
order of display is the most recent fault to the least recent fault.
R F L
ESETTING ROM OCKOUT
Furnace lockout results when a furnace is unable to achieve igni-
tion after three attempts during a single call for heat. It is character-
ized by a non-functioning furnace and a one flash diagnostic LED
code. If the furnace is in "lockout", it will (or can be) reset in any of
the following ways.
1. Automatic reset. The integrated control module will
automatically reset itself and attempt to resume normal
operations following a one hour lockout period.
2. Manual power interruption. Interrupt 115 volt power to the
furnace for 1 - 20 seconds.
3. Manual thermostat cycle. Lower the thermostat so that
there is no longer a call for heat then reset to previous setting.
Interrupt thermostat signal to the furnace for 1 - 20 seconds.
NOTE: If the condition which originally caused the lockout still
exists, the control will return to lockout. Refer to Section XVIII,
Troubleshooting - Diagnostic Chart for aid in determining the cause.
XIX. MAINTENANCE
HIGH VOLTAGE!
T
O AVOID PERSONAL INJURY OR DEATH DUE TO
,
ELECTRICAL SHOCK DISCONNECT ELECTRICAL POWER
BEFORE PERFORMING ANY MAINTENANCE
,
HANDLE THE IGNITER HANDLE WITH CARE
THE IGNITER ELEMENT WITH BARE FINGERS
HANDLING OR VIBRATION COULD DAMAGE THE IGNITER
RESULTING IN PREMATURE FAILURE
SERVICER SHOULD EVER HANDLE THE IGNITER
A
NNUAL INSPECTION
The furnace should be inspected by a qualified installer, or service
agency at least once per year. This check should be performed at
the beginning of the heating season. This will ensure that all fur-
nace components are in proper working order and that the heating
system functions appropriately. Pay particular attention to the fol-
lowing items. Repair or service as necessary.
•
Flue pipe system. Check for blockage and/or leakage. Check
the outside termination and the connections at and internal
to the furnace.
•
Heat exchanger. Check for corrosion and/or buildup within
the heat exchanger passageways.
•
Burners. Check for proper ignition, burner flame, and flame
sense.
39
WARNING
. I
F YOU MUST
. T
OUCHING
,
ROUGH
. O
NLY A QUALIFIED
.