Sequence Of Operation; Example - ICP 9MAC/E series Troubleshooting Manual

You should ALWAYS begin in the START HERE section (see
Index for page number) which will guide you to the appropriate
section where a minimal number of steps will be used to correct the
problem. Once in a section, read the ACTION. An ACTION may
have a number in the GO TO column. Do whatever the ACTION
says, then proceed to the step indicated in the GO TO column.
If the ACTION is a question (a question will have a number in the
YES or NO column), answer it YES or NO. If the answer is YES, go
STEP
1. Step 1 tells us NOT TO REMOVE THE BLOWER DOOR. It then asks the question, "Is
AMBER LED status light ON SOLID, alternately flashing bright-dim-bright-dim like a
heartbeat, or flashing ON and OFF?". If the low pressure switch was defective, a pressure
switch did not open status code would be flashing, so the answer is YES. We go to Step 2.
2. Step 2 asks the question, "Is the AMBER LED status light ON SOLID?". If the low pressure
switch was defective, a pressure switch did not open status code would be flashing, so the
answer is NO. We go to Step 4.
4. Step 4 asks the question, "Is the AMBER LED status light alternately flashing bright-dim-
bright-dim like a heartbeat?". If the low pressure switch was defective, a pressure switch did
not open status code would be flashing, so the answer is NO. We go to Step 5.
5. Step 5 tells us to determine the status code. The status code is a single or two digit number
with the first number determined by the number of short flashes and the second number after
the (+) sign is the number of long flashes. So we count the short flashes and long flashes if
available and see that status code 2 is flashing and go to Step 6.
6. Step 6 tells us to go to status code 2 section.
GENERAL
The furnace must have a 115-vac power supply properly connected
and grounded. Correct polarity must be maintained to enable gas
heating operation.
The gas service pressure must not exceed 0.5 psig (14-in.wc), and no
less than 0.16 psig (4.5-in.wc).
Thermostat wire connections to the furnace at R and W/W1 are the
minimum required for gas heating operation. W2 must be connected
for 2-stage heating thermostats. Y/Y2 and G are required to be
connected to the furnace for single-stage cooling and heat pumps.
Y1, Y/Y2, and G are required for two-stage cooling and heat pumps.
G is required for continuous-fan. C
clock thermostats. These connections must be made at the 24-vac
terminal block on the furnace control. (See Appendix A)
This furnace can be installed with either a single-stage heat/cool or a
two-stage heat/cool thermostat.
CAUTION: This furnace is equipped with a manual
!
reset switch in the gas control area. The switch will open
and shut off power to the gas valve, if a flame rollout or
overheating condition occurs in the gas control area. DO
NOT bypass the switch. Correct inadequate combustion-
air supply, or component failure before resetting the
switch.
Before operating the furnace, check each manual reset switch for
continuity. If necessary, press and release the button to reset the
switch.
440 08 4001 00

EXAMPLE

Start Here Section
ACTION
-24V is required for some
OM
to the step indicated in the YES column. If the answer is NO, go to
the step indicated in the NO column.
Let's try our guide out using the EXAMPLE section below, and see
how it works. Suppose that the problem is a defective low pressure
switch (for example the contacts will not open). This is an internal
problem and cannot simply be seen. We go to the START HERE
section to Step 1.

SEQUENCE OF OPERATION

Using the schematic diagram in Appendix A, follow the sequence of
operation through the different modes. Read and follow the wiring
diagram very carefully!!
Note: If a power interruption occurs during a call for heat (W/W1
or W/W1-and-W2), the control will start a 90-second blower-only
ON period two seconds after power is restored, if the thermostat is
still calling for gas heating. The amber LED light will flash code 12
during the 90-second period, after which the LED will be ON
continuous, as long as no faults are detected. After the 90-second
period, the furnace will respond to the thermostat normally.
The blower door must be installed for power to be conducted through
the blower door interlock switch ILK to the furnace control CPU,
transformer TRAN, inducer motor IDM, blower motor BLWM, hot-
surface igniter HSI, and gas valve GV.
COMMUNICATING CONTROL AND MODULATING
HEATING
Best comfort will be attained when a Communicating Wall Control is
used with this product. Wiring and set-up instructions are provided
with the communicating control. See the furnace data sheet accessory
section for help in selecting the appropriate communicating control
for this furnace.
When a communicating control is used, the furnace will modulate
through its full operation range, or can be limited via the minimum
and maximum cfm configurations.
Operation of the furnace at the beginning and end of each heating
cycle, will be the same as detailed below in the Single-Stage
- 2 -
YES NO GO TO
2 19
3 4
7 5
INDEX
6