Packaged Rooftop Ventilator
26
Optional Dirty Filter Switch
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.
1. Open the filter compartment and place a sheet of
plastic or cardboard over 50% of the filter media.
2. Replace the filter compartment door.
3. Check to see if there is power at the alert signal
leads (refer to electrical diagram).
4. 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.
5. Open the filter compartment and remove the
obstructing material.
6. 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 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)
Start-Up Components