64
To use a memory chip;
1. Power down all HVAC equipment in the system.
2. As when handling any electronic components, discharge
any static electricity you may be carrying by touching
grounded metal.
3. Insert the memory card in the slot on the control board.
4. Power the system back up and allow a few minutes for
the network to establish communication between all de-
vices.
5. Furnace control board will display “OP” or ‘ON” (depend-
ing on board part number).
6. Check operation.
7. Memory chip can be left on the control board (recom-
mended) or removed once equipment is powered down
again.
Safety Circuit Description
A number of safety circuits are employed to ensure safe and
proper furnace operation. These circuits serve to control any
potential safety hazards and serve as inputs in the monitoring
and diagnosis of abnormal function. These circuits are continu-
ously monitored during furnace operation by the integrated con-
trol module.
I
NTEGRATED
F
URNACE
C
ONTROL
(IFC)
The integrated control module is an electronic device which, if a
potential safety concern is detected, will take the necessary pre-
cautions and provide diagnostic information through an LED dis-
play.
P
RIMARY
L
IMIT
The primary limit control is located on the partition panel and
monitors heat exchanger compartment temperatures. It is a nor-
mally-closed (electrically), automatic reset, temperature-activated
sensor. The limit guards against overheating as a result of insuf-
ficient conditioned air passing over the heat exchanger.
A
UXILIARY
L
IMIT
The auxiliary limit controls are located on or near the circulator
blower and monitors blower compartment temperatures. They
are a normally-closed (electrically), auto-reset sensors. These
limits guard against overheating as a result of insufficient condi-
tioned air passing over the heat exchanger.
R
OLLOUT
L
IMIT
The rollout limit controls are mounted on the burner/manifold as-
sembly 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 opera-
tion) negative air pressure-activated switches. They monitor the
airflow (combustion air and flue products) through the heat ex-
changer via pressure taps located on the induced draft blower
and the coil front cover. These switches guard against insuffi-
cient 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 as-
sembly which uses the principle of flame rectification to deter-
mine the presence or absence of flame.
Troubleshooting
HIGH VOLTAGE !
T
O
AVOID
PERSONAL
INJURY
OR
DEATH
DUE
TO
ELECTRICAL
SHOCK
,
DISCONNECT
ELECTRICAL
POWER
BEFORE
PERFORMING
ANY
SERVICE
OR
MAINTENANCE
.
WARNING
Refer to the
Troubleshooting Codes
for assistance in determin-
ing 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 trouble-
shooting the unit.
R
ESETTING
F
ROM
L
OCKOUT
Furnace lockout results when a furnace is unable to achieve igni-
tion after three attempts during a single call for heat. It is charac-
terized 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 auto-
matically reset itself and attempt to resume normal opera-
tions 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.
OPERATIONAL CHECKS
