S9200U Installation Guide

S9200U1000 UNIVERSAL HOT SURFACE IGNITION INTEGRATED FURNACE CONTROL
13 69-2075EF—05
CHECKOUT
Check out the control system:
— At initial installation of the appliance.
— As part of regular maintenance procedures.
— As the first step in troubleshooting.
— Any time work is done on the system.
LED Indicators
The S9200U1000 provides three indicating LEDs; see
Fig. 4 on page 9 for location on board:
— Flame - Amber: indicates flame status
— Status - Red: indicates general system status
and error codes.
— E-COM - Green: indicates EnviraCOM™ bus
activity
See “Troubleshooting” on page 20 for information
about specific flash codes as referenced in the
checkout procedures.
Use the following procedures only for the integrated
furnace control; see individual component
instructions for additional checkout procedures.
I. CHECK NORMAL
OPERATION
Check Conventional 24 Vac
Thermostat
1. Turn on power to the appliance.
2. After power is switched on, the furnace control
can accept a W request after approximately 20
seconds, and Y and G requests after approxi-
mately 10 seconds.
3. Set the thermostat to call for heat. Make sure the
S9200U1000 control sequences the system as
indicated in Fig. 9 on page 18.
4. Set the thermostat below the room temperature
to end the call for heat. The burner should go
out; the induced draft fan should provide Post-
purge time (15 seconds); and after the delay
time, the indoor fan should stop.
There are three modes of operation. They are
discussed in this next section in the following order:
1. Normal Heat Mode
2. Normal Cooling Mode – see page 14
3. Fan Mode – see page 15
Normal Heat Mode
Refer to Fig. 9 on page 18 for the Heat Mode control
sequence diagram. The following describes the
operation during a call for heat and the heat cycle.
Call for Heat
A call for heat is signaled by the thermostat closing
the contacts between R/2 and W or an EnviraCOM™
heat demand. Requests for heat are ignored if there is
a call for cooling at the Y terminal.
Upon a call for heat:
— The S9200U1000 conducts a safe start check
that consists of an internal hardware/software
self-check and verification there is no main
burner flame present.
— The S9200U1000 verifies the Limit and Rollout
switch circuits are closed.
— The S9200U1000 verifies the pressure switch
circuit is open.
— The S9200U1000 energizes the inducer.
— After the Pressure Switch closes, Prepurge
begins.
— After the completion of Prepurge, the HSI is
energized for the Igniter Warm-up Period.
— When the Igniter Warm-up Period expires, the
gas valve is energized and the Trial for Ignition
begins.
— During the Ignition Activation Period, both the
HSI element and the gas valve remain ener-
gized.
— After Ignition Activation, the HSI is de-ener-
gized and the gas valve remains energized for
the Flame Recognition Period.
— The Heat Fan On Delay is started upon enter-
ing Trial for Ignition.
— When flame is sensed during Trial for Ignition,
the
S9200U1000 de-energizes the HSI and pro-
ceeds to normal run mode operation.
— Once the Heat Fan On Delay has expired, the
circulator is energized on heat speed.
Call for Heat Satisfied
When the call for heat has ended:
— The gas valve is de-energized.
— The Postpurge and circulator fan off delay tim-
ings begin when the loss of flame is detected.
— The inducer is de-energized when the Post-
purge Period is completed.
— The circulator is de-energized when the circu-
lator fan off delay has expired.
Ignition Retry
When flame is not sensed during the Trial for Ignition
or is lost less than 10 seconds after exiting Trial for
Ignition:
— The gas valve is de-energized.
— The inducer remains energized during the
Interpurge Period.
— When the Interpurge Period expires, a new Trial
for Ignition is started again for up to a maxi-
mum of two additional trials.
— After the third Trial for Ignition has failed to
light the burner, the S9200U1000 proceeds to
the Interpurge Period followed by the Soft
Lockout, where it remains for the Auto Restart
Delay before beginning another set of ignition
sequences.
— The retry count is cleared if flame is sensed for
longer than 10 seconds after exiting Trial for
Ignition.
Ignition Recycle
When flame is established during Trial for Ignition,
maintained for at least 10 seconds, and then lost:
— The gas valve is de-energized.
— The inducer remains energized during the
Interpurge Period.
— A new Trial for Ignition is started when the
Interpurge Period expires.