COMFORTSTEAM 259942-001 Electronic Humidistat Owner’s Manual

: July 29, 2024
: COMFORTSTEAM

Table of Contents

PRODUCT OVERVIEW
COMFORTSTEAM TM ELECTRONIC HUMIDISTAT
CUSTOMER SUPPORT
References
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Download This Manual (PDF format)

COMFORTSTEAM 259942-001 Electronic Humidistat

COMFORTSTEAM 259942-001 Electronic Humidistat

PRODUCT OVERVIEW

Product OverView

COMFORTSTEAM TM ELECTRONIC HUMIDISTAT

Features

State of Art digital RH sensor
ROOM or DUCT mounting
Reprogrammable Microcontroller
Potentiometer Set-point setting
Out-door temperature sensor for Set-point Reset
Green (ON/OFF) and Red (warning) status LEDs

Specifications

Set-point range.	.20% to 50% Relative Humidity
Accuracy.	±4.5%, without calibration
Linearity	.±1% in the Set-point range
Differential % RH.	. ±2%
Outdoor Temp. Reset Range	between -9 ˚F (-23 ˚C) to 27 ˚F (-3 ˚C)
Outdoor reset Temperature vs.	Set point change
28 ˚F (-2 ˚C) and warmer	No change
27 ˚F (-3 ˚C) to 23 ˚F (-5 ˚C)	42% max,
22 ˚F (-6 ˚C) to 18 ˚F (-8 ˚C)	38% max
17 ˚F (-9 ˚C) to 12 ˚F (-11 ˚C)	34% max,
11 ˚F (-12 ˚C) to 5 ˚F (-15 ˚C)	30% max,
4 ˚F (-16 ˚C) to -2 ˚F (-19 ˚C)	26% max
-3 ˚F (-20 ˚C) to -9 ˚F (-23 ˚C)	22% max,
-9 ˚F (-23˚C) and colder	20% max.

NOTE : these ranges can vary by ±2 %.

The Outdoor Temperature sets the maximum set point of RH internally. If the Dial position is higher, the actual set point will be limited as above.

Installing and Connecting the COMFORTSTEAMTM Humidistat and the Outdoor Sensor

The humidity sensor is not located at the same place in a wall mount or in a duct mount humidistat and therefore the two models of humidistats are not interchangeable. Please see Fig.1a and Fig.1b
Fig. 1a Wall Mount Humidistat

Fig. 1b Back View of a Duct Mount Humidistat
A three wire control cable (not supplied) has to be connected between the wall (or duct) electronic humidistat and the humidifier electronic board at the three terminals marked “H-STAT”. Please respect the sequence and connect GND to GND 24V to 24V ST1 to IN
The outdoor sensor (please see Fig.1c) is supplied with the humidistat (wall or duct mount). It ideally should be installed on an outside wall facing North. This outdoor sensor automatically reduces the setting of the humidistat according to the outdoor temperature in order to avoid condensation on windows during extremely cold days. It does the opposite during the mild days without your having to manually adjust the humidistat. The outdoor sensor is a 10 kilo-ohms NTC thermistor (negative temperature coefficient).
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.

Red LED – Warning light, flashes when abnormal conditions occur
Green LED – Lit when humidistat is calling for humidity
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.
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 humidifier 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.