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OPTIONAL FEATURES
MODULATING HIGH-LIMIT FOR VARIABLE AIR VOLUME AHU’S (VAV)
When the INTAC
®
is set to transmitter mode (menu 502) a modulating high-limit sensor (menu 508) may
be used in addition to the main room or return air humidity sensor. This sensor is located in the supply air
downstream of the steam injection tubes. It is used by the INTAC
®
to gradually reduce the humidifier
output to limit the supply air relative humidity below saturation. It is typically set to a lower RH value than
the on/off mechanical safety humidity high-limit that is wired to the J6 plug terminals 5 and 6. The benefit
to using this modulating sensor is that humidification is maintained without tripping the safety high-limit
humidistat when the supply air temperature or volumetric flow are change abruptly. The INTAC
®
is always
comparing the room/return air humidity and the supply air humidity and choosing control loop the results in
the lowest power level. The setpoint of modulating high-limit should be above the corresponding dew point
of the main room/return air sensor so that eventually the control power will revert back to being controlled
by the room/return air. For example, with a 40%RH setpoint at 70°F room temp your supply air high-limit
setpoint needs to be above 66%RH at 55° F. If not the INTAC
®
will be controlling based on the supply air
humidity. Resulting in poor control over the room/return air RH.
FREEZE PROTECTION/STANDBY WATER TEMP
Using a type K thermocouple probe the INTAC
®
senses the temperature of the tank water and will turn the
power to the heating source on if there is no call for humidity and the tank temperature is below the value
set on MENU 207
OUTDOOR AIR TEMPERATURE SETBACK OPTION
As outside air temperature decreases, it may be desirable to reduce the humidifier output proportionately
to reduce the risk of wetting interior surfaces and windows within a structure. With the optional outdoor air
temperature setback feature, the user is able to select a point at which the humidifier output will begin to
decrease or setback. The factory default is at 32°F and is user-adjustable from 32°F to 92°F.
Applicable settings:
First, it is necessary to know the temperature range of the sensor, which are the
minimum and maximum values. (Example: for the MAMAC Systems
®
TE-211Z-B-B-2-1-E-3, the
range is –30°F to +130°F with a corresponding output current of 4 to 20mA.)
Next go to:
MENU 511 Air Sensor Select “Current” (Corresponds to the type of output)
MENU 512 Air Process Lo Select “4.0” (Corresponds to current range Low)
MENU 513 Air Process Hi Select “20.0” (Corresponds to current range High)
MENU 514 Air Range Lo Select “-30°F” (Corresponds to temp range Low)
MENU 515 Air Range Hi Select “+130°F” (Corresponds to temp range High)
MENU 516 Air Offset Select “0°F” (Offset from 32°F)
Note: when selecting AIR OFFSET, this refers to an offset from 32°F. For example: if you wish the
humidifier setback to begin at 32°F, then the Air Offset amount should be left at 0°F. If you wish the
humidifier setback to begin at 45°F, then the Air Offset amount should be set at 13°F. If you wish the
humidifier setback to begin at 55°F, then the Air Offset should be set at 23°F, and so on. Also, remember
that the above settings are for the given example and may be different for other temperature sensors.
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