Optional Energy Wheel Start-Up; Drive Belt; Adjust The Air Seals; Sequence Of Operation - Greenheck RV Installation, Operation And Maintenance Manual

Optional Energy Wheel
Start-Up
If selected, the energy wheel is installed in the unit's
airstream with one half of the wheel in the intake
airstream and one half in the exhaust airstream. Air
leakage between the two airstreams has to be kept to
a minimum and the wheel has air seals that must be
adjusted for that purpose. The seals must be adjusted
at time of start-up.
Adjustable
Air Seals

Drive Belt

Drive Belt
Inspect the drive belt. Make sure the belt rides smoothly
in the pulley and around the outside of the wheel. Note
the directional arrow and data information shown in the
image.

Adjust the Air Seals

Make sure the unit power supply is locked out.
Disconnect the wiring to the wheel module and pull
the wheel cassette out of the cabinet on its tracks.
Large cassettes are not removable. Then slowly rotate
the wheel by hand to make sure there is no binding or
misalignment.
There is a perimeter seal located around the outside of
the wheel and a diameter seal across the face of the
wheel on both sides. Check to make sure that all air
seals are secure and in good condition.
Adjust the air seals by loosening all the air seal retaining
screws on the bearing support. Using a piece of paper
as a feeler gauge, adjust the seals so they almost touch
the face of the wheel while tugging slightly on the paper.
When the wheel is rotated, there should be a slight tug
on the paper. Tighten the screws, repeat the steps on
the other set of seals.
Push the wheel cassette back into the unit and plug
in the power connector. Turn the main power supply
back on and then observe the operation of the wheel by
opening the wheel access door slightly. Remove filters if
necessary to observe the wheel.
18
Packaged Rooftop Ventilator

Sequence of Operation

Optional Economizer - The economizer will be locked
out when: the outside air is <40°F (- 2°F hysteresis,
adjustable); the unit is operating in dehumidification
mode; or there is a call for heating.
Retaining
Screws
Bearing
Support
Label
Optional Frost Control - The DDC controller will
showing
cassette
output a signal when wheel frosting is occurring which
serial # and
is determined by a temperature set point (OA <5°F –
date code
2°F hysterisis, adjustable) and wheel pressure drop
increase.
Drive Pulley
Alarms Indication - <icroprocessor shall have one
• Stop Wheel: When economizer mode is enabled
and there is a signal for cooling, the wheel will stop
rotating to allow free cooling.
• Idle Wheel: When economizer mode is enabled and
there is a signal for cooling, the wheel will rotate at
a minimum speed to prevent particle build up on the
wheel.
• Modulate Wheel: When economizer mode is
enabled and there is a signal for cooling, the
wheel VFD modulates wheel speed to maintain the
discharge temperature set point.
• Preheat: When frosting is occurring, the preheater
is energized to defrost the wheel. Once the pressure
drop decreases below the set point, the preheater is
de-energized.
• Timed Exhaust: When frosting is occurring, the
supply blower is cycled off. The exhaust blower
shall continue to run, allowing the warm exhaust
air to defrost the wheel. After the 10 minute cycle,
the supply fan is re-energized to continue normal
operation.
• Modulating Wheel: Includes a VFD in addition
to the thermostat and pressure sensor. When
modulating wheel frost control is initiated, the VFD
will reduce the speed of the wheel, which keeps the
exhaust air condition from reaching saturation, thus,
eliminating condensation and frosting. If the outdoor
air temperature is greater than the frost threshold
temperature OR the pressure differential is less
than the set point, the wheel will run at full speed.
If the outdoor air temperature is less than the frost
threshold temperature AND the pressure differential
is greater than the set point, the wheel will run at
reduced speed until the pressure differential falls
below the set point. The temperature and pressure
differential set points are set at the factory, but are
field-adjustable. The VFD will be fully programmed
at the factory.
digital output for remote indication of an alarm
condition. Possible alarms include:
• Wheel Rotation Alarm: Monitors wheel rotation,
and sends a signal to controller (after a 15 second
time delay with no rotation) that signals the
microprocessor to activate an alarm.
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