Reznor SCE Unit Installation Manual - Manual (Page 33)

Form RZ-NA I-SCE, Mfg #207697 Rev 7, Page 33
FIGURE 33 - Dirty Filter
Switch
Set screw (on front of switch)
must be manually adjusted after
the system is in operation.
Negative pressure connection is toward the
"back or bottom" of the switch (senses
blower side of filters)
Positive pressure connection is
toward the "front or top" of the
switch (senses air inlet side of filters)
SERVICE AND
MAINTENANCE
This unit will operate with a minimum of maintenance. To ensure long life and satisfactory perfor-
mance, a furnace that is operating under normal conditions should be inspected every four
months. If the furnace is operating in an area where an unusual amount of dust or soot or other
impurities are present in the air, more frequent inspection is recommended.
2) With the manual valve turned off to prevent flow to the gas valve, connect a manometer to the 1/8” inlet pressure tap in the
valve. NOTE: A manometer (fluid-filled gauge) with an inches water column scale is recommended.
3) With the field-installed manual valve remaining closed, observe the manometer for two to three minutes for an indication of gas
pressure. No pressure should be indicated on the manometer.
If the manometer indicates a gas pressure , the field-installed manual gas valve must be replaced or repaired before the combi-
nation gas valve can be checked.
4) If the manometer does not indicate gas pressure , slowly open the field-installed manual gas valve. After the manometer's
indicated gas pressure has reached equilibrium, close the manual shutoff valve. Observe the gas pressure. There should be no
loss of gas pressure on the manometer. If the manometer indicates a loss of pressure, replace the combination gas valve before
placing the heater in operation.
NOTE: Operational pressure settings and instructions for checking pressure settings are in Paragraph 10.
28. Operating Gas
Valve
Instructions for
Setting Dirty Filter
Switch
With clean filters in place, blower doors closed, and blower in operation, decrease the pressure
setting by adjusting the set screw on the switch clockwise until the filter light is energized or the
screw is bottomed out. At that point, adjust the set screw three full turns counterclockwise or
until the screw is top-ended. At that setpoint the filter light will be activated at approximately 50%
filter blockage.
WARNING: If you turn off the power supply, turn off the gas. See Hazard Levels, page 2.
NOTE: Use only factory-authorized replacement parts.
WARNING: The operating valve is the prime safety shutoff. All gas supply
lines must be free of dirt or scale before connecting to the unit to ensure
positive closure. See Hazard Levels, page 2.
Remove external dirt accumulation and check wiring connections.
The combination gas valve must be checked annually to ensure that the valve is shutting off gas
flow completely.
Instructions :
1) Locate the 1/8” FPT INLET pressure tap on the combination valve (See FIGURE 34).
FIGURE 34 - Connect
manometer to inlet
pressure tap to check gas
flow shutoff.
Single-Stage
Valve
Two-Stage
Valve
1/8" INLET
Pr essure Tap
1/8”
Outlet
Pressure
Tap
1/8" INLET
Pr essure Tap
1/8”
Outlet
Pressure
Tap