OM 1077-1 • MAVERICK I 14 www.DaikinApplied.com
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Pre-Purge
The IFC energizes the low inducer motor, flashes code “2” on
LED, and waits for the low pressure switch to close. If the low
pressure switch does not close within 3 minutes, the control will
energize the high inducer and wait for both pressure switches
to close. The IFC will light on high fire and remain on high fire
for the remainder of the heat cycle.
When the low pressure switch has closed, the IFC stops
flashing the LED and begins timing the 30 second pre-purge
period. If flame is sensed as present during pre-purge, the
IFC restarts the pre-purge time to require a full pre-purge after
flame is removed. When pre-purge time has expired, the IFC
begins the ignition trial.
Ignition Trial
The IFC energizes the gas valve and spark. The IFC ignores
flame sense for the first 2 seconds of the ignition trial. If flame
is not established within 7 seconds, the gas valve and spark
is de-energized and the IFC goes to an inter-purge. If flame is
established, the spark is de-energized, the IFC energizes the
high inducer (low inducer remains energized) and begins heat
blower on delay.
Heat Blower On-Delay
The control waits for 45 second heat fan on delay and then
energizes the indoor blower heat speed. If the blower is
already energized by a call for cooling or continuous fan, or
in a blower off delay period, the on delay is skipped and the
blower remains energized. After the blower on delay time is
complete, the control goes to high fire warm-up mode.
The high pressure switch is ignored during the heat blower
on delay to give time for the high pressure switch to close if
lighting on low fire.
High-fire Warm-up
The IFC remains on high fire for 120 seconds after flame is
established. If the DDC Controller is calling for 2nd stage heat,
the IFC remains in high heat. If the IFC lit on high fire because
the low pressure switch did not close within 3 minutes, then the
IFC remains on high fire for the entire call for heat regardless
of 2nd stage thermostat call. If there is no DDC Controller
demand for 2nd stage heat when the 120 second time has
expired, the IFC transitions from high heat to low heat.
Low Heat
IFC inputs are continuously monitored to ensure limit, rollout,
and pressure switches are closed, flame is established, and
the thermostat call for heat remains. Low gas, low inducer, and
blower remain energized. If the DDC Controller calls for 2nd
stage heat (Hi Heat), the IFC transitions to high heat.
High Heat
IFC inputs are continuously monitored to ensure limit, rollout,
and pressure switches are closed, flame is established, and
the DDC Controller calls for heat remain. Low gas, high gas,
low inducer, high inducer, and blower remain energized. If the
DDC Controller terminates the call for 2nd stage heat and the
first stage call remains, the IFC transitions to low heat.
Low Heat to High Heat Transition
When the DDC Controller calls for 2nd stage heat after low
heat is established, the IFC checks the high pressure switch.
If the high pressure switch is closed, the IFC flashes “2” on
the LED and waits indefinitely for the high pressure switch
to open. When the high pressure switch is proven open,
the IFC energizes the high inducer motor and waits for the
pressure switch to close. If the high pressure switch does
not close within 60 seconds, the control flashes “2” on the
LED and deenergizes the high inducer motor for 5 minutes.
The high inducer is re-energized after the 5 minute period for
60 seconds and the cycle repeats indefinitely until the high
pressure switch closes. When the high pressure switch closes,
the IFC energizes the high gas output and proceeds to high
heat.
High Heat to Low Heat Transition
When the DDC Controller ends the call for 2nd stage heat and
the first stage call remains, the IFC de-energizes the high gas
output. The high inducer remains energized for 60 seconds
after the high gas de-energizes. The IFC proceeds to low heat.
Post Purge
When the DDC Controller demand for heat is satisfied, the
IFC immediately de-energizes the gas valve(s). The Inducer
output(s) remains on for a 5 second post-purge period. The
IFC continues the heat blower off delay.
Heat Blower OFF Delay
The IFC de-energizes the Indoor blower motor 90 seconds
after the call for heat terminated
Interrupted Call For Heat
If the DDC Controller demand for heat is removed before
the ignition period, the IFC will immediately de-energize the
inducer.
If the DDC Controller demand for heat is removed after ignition
has begun, the induced draft motor will run through a post
purge and the indoor blower motor will run on heat speed for
the delay OFF time.
