Instruction Manual
E2 Humidistat 
INTRODUCTION 
Thank you for selecting the GENERALAire E2 
Humidistat. A professional technician should install the 
unit. 
FRONT VIEW 
1.  Operation modes 
2.  Moisture is being added into the environment 
3.  Humidity / temperature reading  
4. 
: Toggle between OFF, MANUAL and AUTO 
modes (if outdoor sensor is connected) 
5. 
: Toggle between indoor humidity and indoor / 
outdoor temperature displays (if outdoor sensor is 
connected) 
6.  °C / °F: Select temperature unit 
7.  Wall mount cover. Squeeze top-bottom to open. 
8.  Humidity index chart 
9.  Outdoor temperature reading is displayed  
10.  Temperature / humidity setting is displayed 
11.  Temperature / humidity offset is displayed 
12.  Indoor temperature / humidity reading i
s dis
played 
13. 
 /  : Increase / decrease setting; enter 
humidity / temperature offset setting 
BACK VIEW
14. 
14.
Removable terminal block for wire connections. 
TO MOUNT THE UNIT 
NOTES 
•  To remove the humidistat from the base, squeeze 
the louvered base at the top and bottom. 
•  To remove the humidistat from the wall, lift up on 
the humidistat and pivot top away from wall 
•  Before wall mounting, please remove the gasket. 
•  Before return air duct mounting, please remove the 
breakout piece. Remove terminal block for wiring. 
•  If return air duct mounting, route wires between 
humidis
tat and base. 
 MOUNT THE OUTDOOR SENSOR 
Mount the sensor outside the house: 
•  Do not mount on South side of the house or in 
direct sunlight. 
•  Place at least 4 feet away from any exhaust vent.
•  If in air intake, place 1 foot or closer to outside wall.
•  Place at least 6” higher than possible snow.
•  Do not route sensor wire near high voltage wires.
WIRING  
WIRING TO 24V. BYPASS HUMIDIFIER
AC L
AC N
HUM
SNSR
OUTDOOR TEMP. SENSOR
(NOT USED IN MANUAL MODE)
HUMIDIFIER 24V.
SOLENOID VALVE
OR 24V. DRUM MOTOR
727-58 24 V. TRANSFORMER
OR 24 VAC POWER SUPPLY
SWITCHED WITH FURNACE OPERATION
JUMPER WIRE
24V OUTPUT FROM HUMIDIFIER (RED WIRES) OR
727-58 24 V. TRANSFORMER SWITCHED WITH FURNACE OR
OR 24 VAC POWER SUPPLY SWITCHED WITH FURNACE.
WIRING TO 1137, 1000 POWER HUMIDIFIER
HUMIDIFIER CONTROL LEADS
(YELLOW WIRES)
OUTDOOR TEMP. SENSOR
(NOT USED IN MANUAL MODE)
AC L
AC N
HUM
SNSR
WIRING TO DS-15, RS-15, CS-15, DS-35,
RS-35, CS-35 ELITE STEAM HUMIDIFIER
AC L
AC N
HUM
SNSR
OUTDOOR TEMP. SENSOR
(NOT USED IN MANUAL MODE)
N2
GND
GND
GND
N1
AB
AB
IN
NO
NO
C
C
NC
24V
ALARM
EXT FAN
TO USE THE UNIT 
Press   to select OFF, MANUAL or AUTO mode (if 
outdoor sensor is connected). 
•  OFF mode: The humidifier is turned off. 
•  MANUAL mode: The E2 will work to maintain the 
single humidity selected. You can set your desired 
humidity level by pressing 
 or  . The humidifier 
will turn ON or OFF according to your manual setting. 
(The humidifier will operate when the measured 
relative humidity falls more than 2% below the set 
point.) Humidity will have to be lowered when weather 
is colder or if condensation is suspected. 
 Suggested Setting Outdoor Temperatures 
  15%    -20  -29  
  20%    -10  -23  
  25%     0 ˚F -18˚C
˚F ˚C
˚F ˚C
˚F ˚C
˚F ˚C
˚F ˚C
  30%    +10  -
12  
  35%    +20  - 7  
  40%    +30  - 1  
•  AUTO mode: The E2 will automatically raise the 
humidity as
 the outdoor temperature increases. This 
provides the highest possible humidity. The E2 will 
automatically lower the humidity as temperatures 
drop. This minimizes the risk of condensation on cold 
surfaces like windows. You can adjust the Auto 
Humidity Index Set Point from 0 (low) to 10 (high) by 
p
ress
ing   or  . The Humidity Index is based on 
the outdoor temperature and indoor humidity. The 
humidifier will switch ON/OFF according to the 
calculated auto humidity index set point. Lower Index 
settings are for older homes with less insulation and 
vapor barriers. Higher Index settings are for newer 
homes with complete vapor barriers, triple pane 
windows and high R-value insulation. If condensation 
occurs 
reduc
e Index setting by 2 points until 
condensation stops. 
NOTE If the outdoor temperature sensor fails, 
flashes and the unit will default to MANUAL mode. 
•  To toggle between indoor / outdoor temperature 
and indoor humidity: Press 
. 
•  To change the temperature unit: Press °C / °F. 
•  To set the temperature / humidity offset in 
MANUAL or AUTO mode: 
1.  Simultaneously press 
 and   when viewing the 
temperature or humidity reading. 
2.  Use 
 or   to change the setting (-3 to 3). 
3.  Press  
 and   simultaneously or wait 5 
seconds to confirm and move onto the next setting.  
•  Lo or Hi will flash on the display when: 
MEASUREMENT 
LO  HI 
Indoor temp. 
Below 0
o
C 
(32
o
F) 
Above 
99
o
F(37
o
C) 
Outdoor temp.  Below -40
o
C 
(-40
o
F) 
Above 50
o
C 
(122
o
F) 
Humidity  Below 10%  Above 90% 
•  If power is lost, current settings are retained. 
PRECAUTIONS 
This product is engineered to give you years of 
satisfactory service. Here are a few precautions: 
•  Do not allow excess humidification. Excess 
humidity can cause condensation and enable mold 
and mildew growth. 
•  Do not tamper with the unit’s internal components. 
The unit contains no user-serviceable parts. 
•  The contents of this manual may not be reproduced 
without the permission of the manufac
turer. 
NOTE The technical specifications for this product and 
the contents of the user manual are subject to change 
without notice. 
SPECIFICATIONS 
TYPE  DESCRIPTION 
Dimensions 
H x W x D 
84 x 84 x 20 mm 
(3.3 x 3.3 x 0.8 in.) 
Weight  95.4 g (3.4 ounces) 
Temperature unit  °F / °C 
Temperature operating 
range 
32°F to 99°F 
-0°C to 37°C 
Temperature resolution  2°F (1 °C) 
Humidity range  10% to 60% 
Humidity resolution  1% 
Power  18-30 Volts, AC 
TECHNICAL SUPPORT 
General Filters, Inc. Tel: 248-476-5100
43800 Grand River Engineering@GeneralFilters.com
Novi, MI 48375 Form 13144 REV. F.
• If Outdoor Temperature is over 50°F or 10°C, a safety
stop will prevent calling for humidity. Test circuit by 
removing one outdoor sensor wire.
• Confirm correct outdoor temperature reading. If 
temperature reading is high, use Diagram for 
GREATER THAN 20 FEET.
WIRING OUTDOOR SENSOR LESS THAN 20 FEET
SNSR
HUM
ACN
ACL
WIRING OUTDOOR SENSOR GREATER THAN 20 FEET
SPLICES: NO MORE THAN
ONE PER LEAD.
20 FEET MAX.
SNSR
HUM
ACN
ACL
SPLICES: NO 
MORE THAN
ONE PER 
LEAD.
300 FEET MAX.
COMMON GROUND
COMMON GROUND examples:
Water pipe, metal duct, household electrical safety ground, conduit.
The wire from the unit and the wire from the sensor must both be 
connected to the same common ground, for example both to water
pipe OR both to the household safety ground.
NOTE: Separate sensor and common ground by at least 4 inches. 
Ex: Don’t lay the wire on the metal conduit or duct used for the ground.
FIELD
SUPPLIED
FIELD
SUPPLIED
®

