Thermolec AcuSteam - Manual (Page 4)

1.4 A two wire control cable is required to connect the outdoor sensor to the terminals marked COM & ODR
on the electronic humidistat. Please see Fig. 1d. The outdoor sensor is not polarized so there is no wiring
polarity to follow.
IMPORTANT : Whenever an outdoor sensor is connected to the electronic humidistat, the jumper located at
the top of the electronic board must be removed so that the outdoor sensor becomes operational (i.e.
the jumper short circuits the terminals dedicated to the outdoor sensor). If the outdoor sensor is not installed,
keep the jumper in place.
1.5 If you decide to use a duct mount humidistat, it has to be installed on the return duct. Please use
the drilling template printed at the end of these instructions. This duct mounting method allows a better
“average sensing” of all the air returned to the furnace, thus offering superior humidity control. However, since
the humidistat has pilot lights giving information about the humidifi er status, they may not be visible if the
humidistat is installed in the basement.
Three holes have to be drilled in the duct, two for screws (approx. 1/8” dia.) and one for sensing (approx. 5/8”
dia.). The humidity sensor is located in the rectangular opening visible at the back of the humidistat baseplate.
This location will prevent potential dust accumulation on the sensor. Please see Fig. 1b.
Warning : Before installing anything on a duct, always check that you are not about to cut or drill into an air
conditioning coil or electrical accessories.
1.6 To force a drain cycle when the humidifi er is running and producing steam, simply turn down the
humidistat. Please note that when using an ACU-STEAM electronic humidistat, if the relative humidity is
extremely low the humidifi er may still run with the knob at the minimum setting because of a range limiter
inside the cover. If this occurs you will need to remove the humidistat cover by pulling it off and turn the knob
counter-clockwise to the minimum setting. The humidifi er should now stop and drain.
Jumper - MUST be removed when outdoor sensor is connected
- remains in place if the outdoor sensor is not used
GND 24V ST1 COM ODR
Fig. 1d
Red LED - Warning light, flashes when abnormal conditions occur
Green LED - Lit when humidistat is calling for humidity
Red
LED
Green
LED
To Humidifier
Baseplate Frontplate
From Outdoor Sensor
GND 24V ST1
GND 24V IN
COM ODR
Red
LED
Green
LED
!
35
30
20
40
50
GND 24VST1 COM ODR ST2 10V