5
Installation
Read the instructions in the furnace installation manual carefully before attempting installation
or operation of the humidifier. Failure to follow these instructions may result in improper
installation and therefore, void the manufacturer’s warranty.
WARNING
Improper electrical wiring can cause personal injury, death, or
property damage. Local codes require that the unit be installed
by a properly qualified HVAC technician or electrician.
Some furnaces provide 120VAC auxiliary terminals that may be used to power the humidifier.
Since these auxiliary terminals are interlocked with the fan, no separate fan interlock relay is
required in the humidistat circuit depending on the furnace model. These terminals are
marked HTG.Acc/Neutrals. Acc/Neutral or Hum-H/Hum-N.
When connected to these furnaces using 120VAC auxiliary terminals interlocked to the furnace
fan, connect the primary of the supplied 120/24VAC transformer to the auxiliary terminals on
the furnace. Connect the secondary of the transformer to the unit pigtails and SPST humidistat
provided. The humidifier will then turn on whenever the furnace fan is running and there is a
call for humidity.
For systems without 120VAC or 24VAC auxiliary terminals, systems with multi-speed blowers or
non-120VAC systems, the switch contacts of a separate SPST-NO fan interlock relay is required
to be wired in series with the humidistat switch. Depending on the installation and furnace
manufacturer the coil for this relay could be:
• Wired in parallel with the coil of the NO fan relay, typically 24VAC.
• Wired in parallel with the common and heating speed tap of the units blower typically
120VAC or 240VAC.
• An inductively coupled current sensing relay on the common of the units blower.
See installation instructions on the provided
mounting template
