Operating Instructions - Models 400, 500, 600 & 700; Automatic Digital Humidifier Control Indicator Lights; Blower Activation - Aprilaire 300 Owner's Manual

MODELS 400, 500, 600 & 700
The Automatic Digital Humidifier Control (ADHC) offers two modes
of operation, Automatic or Manual. An explanation of both modes
follows. (See FIGURE A on page 7 for Automatic mode. See FIGURE B
on page 8 for Manual mode.)
When in the Automatic mode, this system offers the following benefits:
• You will always receive the optimal amount of humidity so
that your home and its furnishings are always protected from
the damaging effects of excess condensation or low humidity
during the heating season. The control automatically adjusts your
home's RH based on the outdoor temperature, increasing the time
maximum comfort is maintained.
• Simple operation with few adjustments. The control eliminates the
need to manually adjust the control when outdoor temperature
changes.

AUTOMATIC DIGITAL HUMIDIFIER CONTROL INDICATOR LIGHTS

Service Required: The red light indicates that the humidifier is not
operating normally and that service is required.
Change Water Panel: The yellow light indicates that it is time to
change the Water Panel in the humidifier. Refer to the ANNUAL
MAINTENANCE section for instructions on changing the Water Panel
or call your HVAC contractor for service.
Humidifier On: The green light indicates that the humidifier is actively
adding healthy humidity to your home.

BLOWER ACTIVATION

The BLOWER ACTIVATION switch is set to the ON position to allow the
humidifier control to activate the HVAC system fan for maximum
humidification. For this setting the Models 500, 600 and 700 must be
connected to hot water.
This function will operate in two ways:
1. If the HVAC system has been idle for one hour, the humidifier
control will activate the HVAC system fan to sample the air for 3
minutes. If the RH is lower than the set point, the humidifier control
will activate the humidifier and keep the fan running.
2. If the RH set point has not been reached by the end of a call for
heat, the control will continue to operate the humidifier and the
HVAC system fan.
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OPERATING INSTRUCTIONS –