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ACC-APG002A-EN
Conventional Thermostat Sequence of Operation
When the Precedent system is configured to operate with a conventional thermostat, the controller
provides protection for the system (see General Support Sequence section) and continues to provide
insight to operating conditions. A conventional thermostat can be applied with CVZT and single zone
VAV configured systems. While not recommended, a conventional thermostat can be applied to single
zone variable volume configured systems, but the system is limited to staged fan control instead of a
fully variable sequence.
When under conventional thermostat control, the equipment responds directly to operating requests
from the thermostat device. Each thermostat input corresponds to a specific unit function, as described
in the following tables. Equipment protection functions and compressor minimum on/off timers remain
in-control, even when under conventional thermostat control.
Table 2. Cooling only, without outside air
Inputs Outputs
X Y1 Y2 W1/O W2 G
Supply Fan
On/Off
Request
Supply Fan
Speed
Request
Compressor
Cool Stage
Request
Auxiliary
Heat Stage
Request
Heat Cool
Mode Status
NA OPEN OPEN OPEN OPEN CLOSED ON Min None None
Fan Only
NA OPEN OPEN CLOSED OPEN X ON Min None
Stage 1
Heat
NA OPEN OPEN X CLOSED X ON Min None
Full Stage
Heat
NA CLOSED OPEN OPEN OPEN X ON Min
Stage 2
None Cool
NA OPEN CLOSED OPEN OPEN X ON Min
Stage 2
None Cool
NA CLOSED CLOSED OPEN OPEN X ON Max
Full Stage
None Cool
NA X X X X X OFF 0 None None OFF
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