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 unit control center.
To adjust the switch, the unit must be running with all of the access doors in place. 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.
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 blower side of filters)
Positive pressure connection is toward the ‘back or bottom’ of the switch. (senses air inlet side of filters)
CO2 Sensor
This accessory is often used to provide a modulating control signal to a variable frequency drive to raise and lower airflow in relationship to the CO2 levels in the space. This strategy is often referred to as Demand Control Ventilation and provides further energy savings to the system. Follow instructions supplied with sensor for installation and wiring details.
Service Outlet
120 VAC GFCI service outlet ships loose for field installation. Requires separate power source so power is available when unit main disconnect is turned off for servicing.
Vapor Tight Lights
Vapor tight lights provide light to each of the compartments in the energy
recovery unit. The lights are wired to a junction box mounted on the outside of the unit. The switch to turn the lights on is located in the unit control center. The switch requires a separate power source to allow for power to the lights when the unit main disconnect is off for servicing.
Model PVe Heat Recovery Unit 15