Sensors And Lights; Rotation Sensor - Greenheck HRE-20 Installation, operationand Maintenance Manual

OPTIONAL ACCESSORIES

Rotation Sensor

The rotation sensor monitors energy recovery 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 inlet compartment) . Model ERV units
require the opening around the control center
to be covered (with cardboard, plywood, etc .)
to set up dirty filter switch . 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) . If there
is no power, turn the adjustment screw on
the dirty filter gauge clockwise until you have
power . 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 .
Setscrew (on front of switch) must be manually
adjusted after the system is in operation .
Positive pressure connection is toward the
"front or top" of the switch (senses air inlet
side of filters)
Negative pressure connection is toward the "back or bottom"
of the switch (senses blower side of filters)
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