Sequence Of Operation; Cooling; Heat; Integrated Furnace Control - Daikin Maverick I Installation And Maintenance Manual

Sequence of Operation

Sequence of Operation
Important - The DDC Controller is shipped with the control
disabled so units do not accidentally energize during
installation. The commissioning of the rooftop unit therefore
requires the configuration of the Occupied Mode menu prior to
initial startup. See Occupied Mode‚ page

Cooling

When the DDC Controller receives a call for cooling via
thermostat or zone sensor compressor 1 energizes. After the
indoor fan on delay (1-180 sec / default 10 sec) the indoor fan
energizes. The indoor fan on delay starts when the call for
cooling is initiated.
When used in local zone sensor mode of operation, the DDC
Controller satisfies the set point using all or a partial number
of stages available. When cooling demand exists, the DDC
Controller will stage up in the following order: Economizer,
First Stage Cooling, and Second Stage Cooling based on
demand.
When used in local thermostat mode of operation, the DDC
Controller allows the thermostat to control the demand for
cooling. When cooling demand exists, the DDC Controller
will stage up in the following order: Economizer, First Stage
Cooling. Only two stages will be allowed to energize, so if the
economizer is active then the first stage mechanical cooling
will become second stage and second stage mechanical
cooling will not be used.

Heat

When in heating mode of operation, the DDC Controller
satisfies the set point using all or a partial number of stages
available. When heating demand exists, the DDC Controller
will utilize heat sources in the following order of priority as
available: Gas Heat and Electric.
When the heat demand requires multiple heating outputs at the
same time, a minimum staging delay of 5 seconds between
energizing and de-energizing heating outputs is necessary to
prevent the inrush current startup of multiple loads. The inter
stage is adjustable between 5 and 50 seconds.
The source of demand, like the other modes of operation, is a
result of one of either thermostat or remote sensors.

Integrated Furnace Control

The Integrated Furnace Control (IFC) is external to the DDC
Controller, and on units so equipped, controls the furnace and
gas valve operation based on signals from the DDC controller.
The IFC also provides furnace troubleshooting information via
LED flashing fault codes. When a fault condition exists, the
LED (see Figure 6) flashes the number of times indicated by
the code number, pauses, and repeats.
12
Figure 6: Integrated Furnace Control Status LED
17.
Table 6: Integrated Furnace Control Fault Codes
Call for Heat
After a call for heat the IFC checks to ensure the high
temperature limit and rollout switches are closed. If either is
open, the IFC responds with a fault code. If high limit and
rollout switches are closed, the IFC checks that both pressure
switches are open. If either pressure switch is closed, the IFC
will respond with a fault code and it will flash code "2" on the
LED, waiting indefinitely for both pressure switches to open.
If both pressure switches are open, the IFC proceeds to pre-
purge.
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.
LED
Code
1 Failure To Detect Or Sustain Flame
2 Pressure Switch Or Inducer Problem Detected
3 High Limit Protection Deice Open
4 Gas Valve Not Energized Or No "W" Signal
5 Flame Toll Out Switch Open
Meaning
McQuay OM 1077