28
Model RT Energy Recovery Unit
Rotation Sensor
The rotation sensor monitors energy wheel rotation.
If the wheel should stop rotating, the sensor will
close a set of contacts in the unit control center. Field
wiring of a light (or other alarm) between terminals R
& 12 in the unit control center will notify maintenance
personnel when a failure has occurred (refer to
Remote Panel Wiring Schematics section for wiring
details).
Dirty Filter Sensor
Dirty filter sensors monitor pressure drop across the
outdoor air filters, exhaust air filters, or both. If the
pressure drop across the filters exceeds the set point,
the sensor will close a set of contacts in the unit
control center. Field wiring of a light (or other alarm)
to these contacts will notify maintenance personnel
when filters need to be replaced. The switch has not
been set at the factory due to external system losses
that will affect the switch. This switch will need minor
field adjustments after the unit has been installed
with all ductwork complete. The dirty filter switch is
mounted in the exhaust inlet compartment next to the
unit control center or in unit control center.
To adjust the switch, the unit must be running with
all of the access doors in place, except for the
compartment where the switch is located (exhaust
intake compartment). The adjusting screw is located
on the top of the switch. Open the filter compartment
and place a sheet of plastic or cardboard over 50%
of the filter media. Replace the filter compartment
door. Check to see if there is power at the alert
signal leads (refer to electrical diagram). Whether
there is power or not, turn the adjustment screw on
the dirty filter gauge (clockwise if you did not have
power, counterclockwise if you did have power) until
the power comes on or just before the power goes
off. Open the filter compartment and remove the
obstructing material. Replace the door and check to
make sure that you do not have power at the alert
signal leads. The unit is now ready for operation.
Microprocessor (DDC) Temperature
Control Package
The RT may be controlled either by owner-supplied
and installed controlling devices or it may be
optionally equipped with a microprocessor (DDC)
control package. The DDC control package allows
for stand-alone operation of energy recovery units. It
permits integration of owner-supplied devices such as
room thermostats, dehumidistats or CO
2
sensors. The
controller regulates the temperature of air discharged
from the unit. It can work in response to either
temperature sensors in the discharged air (discharge
control) or it will respond to room temperature
sensors (room control).
Room control requires a temperature sensor or room
thermostat that will call for either heating or cooling to
be wired to the controller. Room thermostats may be
supplied by the owner or may optionally be provided
by FHP.
Typical DDC Controller
(refer to unit-specific documentation)
Setscrew (on front of switch)
must be manually adjusted after
the system is in operation.
Negative pressure connection
is toward the ‘front or top’ of
the switch.
(senses pressure on
the blower side of filters)
Positive pressure connection is toward the ‘back or
bottom’ of the switch.
(senses pressure at air inlet
side of filters)
