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Using Modulating SK300 Humidifier as On/Off

Can You Turn Me On or Off?

Using Modulating SK300 Humidifier as On/Off

Ordered a modulating humidifier but have on/off controls? No problem, we have a solution for you!

The SK300 modulating units are capable to operate as an on/off unit with digital controls.

With these simple instructions, the SK300 humidifiers can be in operation in no time.

Instructions for the SK300 series without BACnet:

  1. Install the on/off humidistat in series with the PD switch (air pressure switch) between terminal 1 and 2.
  2. Install a wire between terminal 2 and 6. Terminal 2 provides 5Vdc to terminal 6 in order to simulate the actual humidity level at 50% RH.


  3. Using Modulating SK300 Humidifier as On/Off

  4. Press the Menu button to access programming mode. The first item is SETPOINT OUT (external control). To switch to INT (internal set point), press and hold the TEST button, located on the main PC board until INT is displayed.
  5. Set the SETPOINT INT value above 60%.
  6. The humidifier will be operating on full demand, use the contact between terminal 1 and 2 to enable and disable the humidifier


Using Modulating SK300 Humidifier as On/Off

Instructions for the SK300 series with BACnet:

  1. Install the on/off humidistat in series with the PD switch (air pressure switch) between terminal F and
    Note: When the On/Off thermostat is open, the LCD displays AIR FLOW OPEN instead of DEMAND 0%


  2. Using Modulating SK300 Humidifier as On/Off

  3. Press the Menu button to access programming mode. The first item is CONTROL EXTERNAL. Press the UP or DOWN button to select INTERNAL.
  4. Leave the default values for following steps in the menu
  • SP SOURC INTERNAL and
  • DUCT SRC DISABLE
Using Modulating SK300 Humidifier as On/Off

David Wond photo