Space Temperature Control: Electric Heat; Discharge Air Temperature Control: Electric Heat; Staged Electric Heat - Trane Tracer AH540 Setup And Operation

CNT-SVX05B-EN
Cooling modes of operation (except dehumidification)
•
Anytime the supply fan is Off
•
Electric heat operation is restricted to heating modes of operation. When
staged electric heat is mounted in preheat position (before cooling capac-
ity), the controller will not allow the use of electric heat for mixed-air pre-
heat control. If mixed-air temperature control is desired because of
installed hydronic capacity, mixed-air temperature control should be used
rather than mixed-air preheat control.

Space temperature control: Electric heat

For space temperature control applications, the Tracer AH540/541 per-
forms cascade space temperature control and stages electric heat capacity
up and down based on the discharge air temperature and discharge air
temperature setpoint.

Discharge air temperature control: Electric heat

For discharge air temperature control with variable-air-volume fan opera-
tion, the Tracer AH540/541 provides electric heat operation only with the
following sequences:
Morning warm-up
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Daytime warm-up
•
Unoccupied mode
•
If one of these sequences is initiated, the VAV boxes are controlled to their
fully open position or to the maximum air flow setpoint. The controller
responds by modulating the supply fan speed to maintain the duct static
pressure at the duct static pressure setpoint (see "Variable-air-volume
supply fan operation: Duct static pressure" on page 51).
The controller will delay electric heat operation for the maximum heat
delay time (4 minutes default, configurable). Because duct static pressure
control is always maintained, maximum heat delay allows time for the
VAV boxes to fully open and allows the air handler to establish full air-
flow before electric heat operation begins.

Staged electric heat

The controller stages the heaters On sequentially, adding 1 stage every 2
minutes. In the unoccupied heating mode, the supply fan will delay turn-
ing Off for 120 seconds after electric heat capacity stages Off to remove
residual heat.
The controller supports two methods of controlling staged electric heat:
Staged electric heat using binary outputs
•
Staged electric heat using a sequencer
•
Staged electric heat using binary outputs
One to four electric heat stages can be directly controlled from binary out-
puts. Since the controller binary outputs can also be configured for stages
Electric heat operation
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