53
R
OLLOUT
L
IMIT
The rollout limit controls are mounted on the burner/manifold assembly and monitor the burner flame. They are normally-closed
(electrically), manual-reset sensors. These limits guard against burner flames not being properly drawn into the heat exchanger.
P
RESSURE
S
WITCHES
The pressure switches are normally-open (closed during operation) negative air pressure-activated switches. They monitor the
airflow (combustion air and flue products) 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 conditions.
F
LAME
S
ENSOR
The flame sensor is a probe mounted to the burner/manifold assembly which uses the principle of flame rectification to determine the
presence or absence of flame.
T
ROUBLESHOOTING
E
LECTROSTATIC
D
ISCHARGE
(ESD) P
RECAUTIONS
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 servicing to protect the integrated control module from damage. By
putting the furnace, the control, and the person at the same electrostatic potential, these steps will help avoid exposing the inte-
grated control module to electrostatic discharge. This procedure is applicable 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 furnace away from 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
IAGNOSTIC
C
HART
Refer to the
Troubleshooting Codes
for assistance in determining
the source of unit operational problems. The dual 7-segment LED
display will display an error code that may contain a letter and
number. The error code may be used to assist in troubleshooting
the unit.
R
ESETTING
F
ROM
L
OCKOUT
Furnace lockout results when a furnace is unable to achieve ignition after three attempts during a single call for heat. It is character-
ized by a non-functioning furnace and a
E 0
code displayed on the dual 7-segment display. 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.
3. Manual thermostat cycle. Lower the thermostat so that there is no longer a call for heat for 1 -20 seconds then reset to
previous setting.
NOTE:
If the condition which originally caused the lockout still exists, the control will return to lockout. Refer to the
Troubleshooting
Codes
for aid in determining the cause.
HIGH VOLTAGE !
T
O
AVOID
PERSONAL
INJURY
OR
DEATH
DUE
TO
ELECTRICAL
SHOCK
,
DISCONNECT
ELECTRICAL
POWER
BEFORE
PERFORMING
ANY
SERVICE
OR
MAINTENANCE
.
WARNING
