Space Temperature Control - Trane LPC Install And Operation Instructions

LPC-SVX01C-EN
Operation
Electric heat operation can produce high
discharge air temperatures if the unit air
flow rate is low or the entering air
temperature is high. The controller
provides an electric heat discharge high
limit control in addition to functional and
safety limits of the product. In draw-
through unit configurations in which the
electric heat source is positioned before
the supply fan in the air stream, the
discharge air temperature is limited to
115°F (default). Blow-through electric
heat unit configurations allow a dis-
charge-air-control high limit of 135°F .
The Tracer AH540/541 controller sup-
ports only unit configurations with one
source of heating capacity, with the
exception of a two-pipe changeover unit
with electric heat, if the controller is
configured for space temperature control
(see "Two-pipe changeover"). When
hydronic-heating capacity is available,
electric heat operation is disabled. If
hydronic-heating capacity is not avail-
able, electric heat is enabled.
Electric heat is normally disabled during:
• Hydronic heating (two-pipe changeover
unit)
• Building automation system
mechanical heating lockout is active
• 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 preheat
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.
sequence of
operation

Space temperature control:

Electric heat
For space temperature control
applications, the Tracer AH540/541
performs cascade space temperature
control and stages electric heat capacity
up and down based on the discharge air
temperature and discharge air
temperature setpoint.
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 turning 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 binary
outputs
One to four electric heat stages can be
directly controlled from binary outputs.
Because the controller binary outputs can
also be configured for stages of DX
cooling the binary outputs are assigned
as follows where the number of electric
heat stages plus the number of DX
cooling stages cannot exceed four
outputs.
1. BO3: DX cooling stage 1 or Electric
heat stage 4
2. BO4: DX cooling stage 2 or Electric
heat stage 3
3. BO5: DX cooling stage 3 or Electric
heat stage 2
4. BO6: DX cooling stage 4 or Electric
heat stage 1
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