Intertek ACVC96 Service Instructions Manual page 42

SYSTEM OPERATION
the gas valve will be de-energized and another purge will
occur and a third ignitor warm up for an additional (2)
seconds will occur. The control will cycle the gas valve a
total of three (3) times before it determines it cannot
establish measurable combustion and enters a locked
out state. The diagnostic error code for this problem is
E0. The control can be reset and brought out of lockout
mode by turning the thermostat off for more than (5) sec-
onds and less then (20) seconds and then back on. It
can also be reset by turning off the electrical disconnect
switch to the furnace for a minimum of 5 seconds.
NOTE: The control board will automatically reset one hour
after lockout occurs. If the furnace frequently has to be re-
set, it means that a problem exists that should be corrected.
Refer to Troubleshooting Chart - ComfortNet™ on the fol-
lowing pages for aid in determining the cause.
3. Low Stage Pressure Switch Stuck Closed. If the con-
trol senses the low stage pressure switch is closed when
the induced draft blower is off, it waits until the fault is
corrected. The diagnostic error code for this problem is
E1. The probable cause is either a faulty pressure switch
or wiring.
4. Low Stage Pressure Switch Stuck Open. If, after the
induced draft blower is energized, the low stage pres-
sure switch does not close within 5 minutes, the control
will go into a 1-hour lockout. The control will automati-
cally reset fro lockout and restart the ignition sequance.
The diagnostic error code for this problem is E2. The
probable causes are either disconnected hose to the
pressure switch, faulty pressure switch or wiring, re-
stricted air intake or flue piping.
5. Open Primary, Auxiliary, or Rollout Limit. If the limit
control opens, the air circulator blower and induced draft
blower will be turned on until the limit closes. The diag-
nostic error code for this problem is E3. The probable
cause is either low conditioned air flow due to dirty filter
or resistance in duct work, faulty limit, faulty blower,
blower speed set to low, misaligned burners, faulty in-
duced draft blower, or blocked flue.
6. Flame Sensed with No Call for Heat. If the control
senses a flame when the gas valve is de-energized, it
will run the air circulation blower and the induced draft
blower continuously with no further furnace operation.
The diagnostic error code for this condition is E4. The
probable causes are either a short to ground in flame
sense circuit, miswiring, lingering burner flame or a slow
closing gas valve.
7. Open Fuse. If the control detects an open fuse, it will
inhibit all furnace operation, except the display of the
error code. The diagnostic error code for this condition
is E5. The probable cause is a short in the low voltage
wiring, either internal to the furnace or external to the
furnace.
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8. Low Flame Sense Signal. If the furnace continues to
operate and the micro-amp signal from the flame sensor
falls below specified level. The diagnostic error code for
this problem is E6. The probable cause is either a coated/
oxidized sensor, incorrectly positioned senser in burner
flame or lazy burner flame due to improper gas pressure
or combustion air.
9. Check Igniter or No Ground Condition. Check for
broken or improperly connected igniter. Check for proper
ground and correct. The diagnostic error code for this
problem is E7.
10. High Stage Pressure Switch Stuck Closed. If the con-
trol fails to operate at high stage heat when commanded
to do so, the high stage pressure switch is stuck closed.
For this condition, the furnace will operate at low stage
only, regardless of the thermostat demand. The diag-
nostic error code for this condition is E8. The probable
cause is sticking high stage pressure switch contacts
or a short in the high stage pressure switch wiring.
11. High Stage Pressure Switch Stuck Open. This con-
dition can occur if the pressure switch hose is blocked
or pinched. Check for blocked flue and/or inlet air pipe.
Blocked drain, weak induced draft blower and malfunc-
tioning pressure switch are possible. The diagnostic
error code for this problem is E9 followed by a pause.
12. Reversed Polarity. If the 115V or 24V AC power leads
are reversed, the furnace will fail to operate. The diag-
nostic error code for this problem is EA. The probable
cause is either the 115V AC power to furnace or inte-
grated control module is reversed, the 24V AC wires to
transformer are reversed, or poor unit ground.
13. No Shared Data. The control does not contain any
shared data. Shared data sets contain all the informa-
tion required to drive the variable speed motor as well as
calculate airflow demands. The furnace cannot function
without the approriate shared data set. The diagnostic
error code for the this condition is d0. A memory card
must be used to populate shared data to the control.
Contact your distributor to obtain the appropriate memory
card for your particular furnace model.
NOTE: Turn off power to the furnace prior to inserting memory
card onto the control. With memory card inserted onto con-
trol, turn power to furnace on. Control has accepted memory
card data once control displays ON on the dual, 7-segment
display. Memory card may be left on control or removed
and used on another furnace of the same model. Turn power
off to furnace prior to removing memory card.
14. Invalid Memory Card Data. This condition occurs if
the control rejects the shared data set on a memory
card. Memory cards are model specific. If a memory
card for a different model is used to populate data to a
specific furnace, if will be rejected by the control. If us-
ing a memory card to populate shared data to a control,
ensure the memory card is specific to the furnace. The
diagnostic error code for this condition is d4.