• Mount the switch at least 6 in. (152 mm) upstream from an elbow or junction, and at
least 15 in. (381 mm) downstream from an elbow or junction.
• Locate the switch on the opposite side of the duct from the air entrance. (See Fig.
1-3 in S688 Installation Instructions.)
Selecting Location for Humidistat
• Select a location for the humidistat on the return plenum or on the wall in the living
space.
— Mounting on the return plenum is the easiest installation for the control wiring
circuit.
For return duct mounting, the humidistat should be mounted upstream from the
humidifier or bypass so that it is properly sensing the relative humidity of the living
space. Locate the control at least 8 in. (203 mm) upstream from the humidifier in the
return air duct. (See Fig. 2.)
Locating Closest 120V Electrical Outlet
• Select location with access to an outlet. If not available, contact an electrician to
have one installed.
• Make sure that the humidifier cord is adequate to reach from the humidifier to the
outlet.
• Make sure that the 20 ft (6.2m) of thermostat wire is adequate to reach from the
humidifier solenoid, to the sail switch, to the humidistat.
Installing the Humidifier
WARNING
Hazardous Voltage
Can cause personal injury or equipment damage.
Do not cut or drill into any air conditioning or electrical accessory.
HE220 AND HE260 BY-PASS FLOW-THROUGH HUMIDIFIER
ALTERNATE LOCATION
RETURN
AIR
6 in. (152 mm)
MINIMUM
BEST
LOCATION
RETURN AIR DUCT
Fig. 2. Selecting duct location for humidistat.
15 in. (381 mm)
MINIMUM
7
RETURN
AIR
M12831A
69-1111EF—05