Aprilaire 448 - Manual (Page 11)

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Inspection and Service Instructions
1. Disconnect electrical power to the
furnace and shut off water supply.
2. Disconnect the water line at the inlet
compression nut.
3. Remove the in-line strainer from inside
the inlet side of the valve by using a
small nail or wire.
4. Flush the in-line strainer clean or
replace with a new strainer, Service
Department, Part No. 4004.
5. Replace the in-line strainer and
reconnect the inlet water line (Double
Wrench To Prevent Leaking).
6. Disconnect the water line at the outlet
compression nut.
7. Remove the orifice from the copper
or plastic tube and make sure this
small opening is unplugged.
8. Replace the orifice and reconnect the
outlet water line (Double Wrench To
Prevent Leaking).
9. Turn on water supply and reconnect
electrical power to the furnace.
OUTLET
COMPRESSION
NUT
ORIFICE
INLET
INLET
COMPRESSION
NUT
SOLENOID
VALVE
IN-LINE
STRAINER