Entering Fan Temperature Sensor; Duct High Pressure Limit; Variable Frequency Drive Operation; Convenience Receptacle/Section Lights - Daikin Rebel Applied DPSA Installation And Start-Up Manual

Entering Fan Temperature Sensor

The entering fan temperature (EFT) sensor and an associated
"Lo Airflow Problem" alarm are provided on VAV units with
MicroTech 4 control and gas or electric heat. The EFT sensor
is located in the supply fan section of the unit at the supply air
funnel.
Heat is disabled whenever the airflow is detected to be too low
for safe heating operation. This condition is indicated when the
supply air temperature exceeds the mixed air temperature by
more than 60°F (16°C).
NOTE: This value is not always 60°F. It depends on whether
the unit is gas or electric heat and on the burner/
baffling arrangement on gas heat units.
In this case, a "Lo Airflow Problem" alarm is generated and
heat is not enabled until the alarm is manually cleared. Refer
to the operation manual for information on clearing alarms
1288).

Duct High Pressure Limit

The duct high pressure limit control (DHL) is provided on all
VAV units. The DHL protects the duct work, the terminal boxes,
and the unit from over pressurization, which could be caused
by, for example, tripped fire dampers or control failure. The
DHL control is factory set to open when the discharge plenum
pressure rises to 5.0ʺ wc.
If the DHL switch opens, digital input DI5 on the Main Control
Board de-energizes. The MicroTech 4 controller then shuts
down the unit and enters the Off-Alarm state. The alarm must
be manually cleared before the unit can start again.
Refer to the operation manual supplied with your unit for more
information on clearing alarms

Variable Frequency Drive Operation

Refer to the vendor instructions supplied with the unit.

Convenience Receptacle/Section Lights

A Ground Fault Circuit Interrupter (GFCI) convenience
receptacle is provided in the main control box. Both unit-
powered and field-powered versions are offered.
Optional lights are available for certain sections in the unit.
Each light includes a switch and convenience receptacle and is
powered by the external 115V power supply connected to TB7.
www.DaikinApplied.com
(OM 1288).

Propeller Exhaust Fan Option

Economizer units may include propeller exhaust or centrifugal
return fan options. This section covers maintenance and
operating instructions for the propeller exhaust option.
Centrifugal return fan construction, maintenance and operation
is similar to supply fans and covered in other sections of this
manual.
Figure 45: Fan Rotation
(OM
Figure 46: Three Fans with Bottom Return
39
Unit Operation
IM 1287 • REBEL APPLIED ROOFTOP