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Safety, Installation, and Operation Manual

Automatic Steam Humidifier Control

READ COMPLETE INSTALLATION INSTRUCTIONS BEFORE STARTING.

WARNING

1. 240 volts may cause serious injury from electrical shock. Disconnect
electrical power to the Steam Humidifier before starting installation.
2. Sharp edges may cause serious injury from cuts. Use care when
cutting plenum openings and handling ductwork.
WARNING This product must be installed by a qualified heating and air conditioning contractor. Failure to do so
could result in serious injury from electrical shock or damage to product and voids product warranty due
to possible product misapplication.

CAUTION

1. Do not set humidity higher than recommended. Condensation
damage may result.
2. Do not set humidity up to recommended levels if there is
condensation on the inside of windows. Condensation damage
may result.
3. Do not mount Automatic Steam Humidifier Control on supply
plenum or duct. High supply temperatures will cause the control
to malfunction.
4. When installing Automatic Steam Humidifier Control on downflow
furnaces, ensure blower continues to run after a heat call is
satisfied to eliminate high temperatures from damaging the
Automatic Steam Humidifier Control.
5. Do not configure Automatic Steam Humidifier Control for
Modulating Control (jumper JP2 set to 1 & 2) when connected to a
Model 1150 Steam Humidifier. Failure of humidifier may result.
THESE INSTALLATION INSTRUCTIONS ARE FOR THE AUTOMATIC STEAM HUMIDIFIER CONTROL ONLY!
For Aprilaire®Humidifier installation, follow Aprilaire Humidifier Installation Instructions.

PRINCIPLES OF OPERATION

The Aprilaire Automatic Steam Humidifier Control is designed to be
installed in the return duct of the HVAC system. The control strategy of the
Automatic Steam Humidifier Control is matched to the humidifier being
controlled: when used with a Model 1150 Aprilaire Steam Humidifier, the
Control supplies an on/off signal to the humidifier. When used with a
Model 1160 or 1180 Aprilaire Steam Humidifier, the Control supplies a
modulating signal to the humidifier. In terms of outdoor temperature
compensation, the Control can be set up in automatic or manual mode,
regardless of the humidifier model being controlled. The automatic mode
incorporates the supplied Outdoor Temperature Sensor to automatically
adjust the control set-point based on the outdoor temperature. The manual
mode does not require an outdoor temperature measurement and is used
for specific set-point control with the control set-point manually adjusted by
the user. The Automatic Steam Humidifier Control will accurately control
the humidity in the conditioned space within the range of 15% – 55% RH.
CONTROL TYPE
ON/OFF CONTROL FOR MODEL 1150
The Automatic Steam Humidifier Control sends a 10 VDC signal to the
humidifier when the measured return air relative humidity is 3% or more
below the set-point. This energizes the humidifier at 100% output. The
Steam Humidifier is either on at 100% capacity or it is off.
MODULATING CONTROL FOR MODEL 1160 & 1180
The Automatic Steam Humidifier Control sends a signal to the humidifier
between 0 and 10 VDC based on: a) the difference between measured
relative humidity and set-point relative humidity, and b) where this
difference or ‘error’ falls within an adjustable proportional control band.
The output of the Control, and therefore the Steam Humidifier, is a
‘proportion’ of maximum output based on ‘a’ and ‘b’ above. See Figure 1
for graphical representation of the output.