Daikin Maverick I Installation And Maintenance Manual page 68

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 de-
energizes 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.
McQuay OM 1077
Sequence of Operation
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.
Ignition Retry
If flame is not established on the first trial for ignition period,
the induced draft motor remains energized and the IFC de-
energizes the low gas valve. The IFC waits for a 60 second
inter-purge period then attempts an ignition re-try. If the
second ignition trial is unsuccessful, the IFC energizes the high
inducer and waits indefinitely for the high pressure switch to
close. When the high pressure switch closes, the IFC energizes
the high gas output, interpurges 60 seconds and tries the 3rd
and 4th ignition attempts on high fire.
If flame is not established on the fourth trial for ignition, the
IFC de-energizes the high and low gas outputs and goes into
lockout. The IFC indicates a fault by flashing the status LED 1
time to indicate lockout is due to failed ignition.
Ignition Recycle
If flame is established and maintained during the trial for
ignition period and then flame is lost, the gas valve is de-
energized, the induced draft motor continues to run, and the
control begins timing the pre-purge delay. The indoor blower
motor will be energized and/or remain energized on heat speed
for the delay off time.
When the pre-purge delay is over, the control energizes the
spark and gas valve for an ignition attempt. If ignition is
unsuccessful, the IFC will attempt up to 3 more retries as
described above. The IFC will recycle up to 17 flame losses (16
recycles) within a single call for heat before going to lockout.
The IFC status LED will flash 1 time if lockout is due to too
many flame loses. (This is same flash code as failed ignition.).
Open Limit switch
The limit switch is ignored unless a call for heat is present. If
the limit switch opens while a call for heat is present, the
indoor fan is energized on heat speed and both inducers are
energized. The gas valve is de-energized if it was energized.
The status LED will flash 3 times indicating the Limit switch
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