CARNES HXHAS User manual

READ AND SAVE
THESE INSTRUCTIONS
COmmERCIAl HUmIDISTAT
OwNERS mANUAl AND
qUICk REfERENCE gUIDE
mODElS
HXHAS, HXHAST,
HXHAw, HXHAwT
FORM 16767
ISSUED: 03-10-21

2 Form 16767
Safety Cautions | COMMERCIAL HUMIDISTAT
CAUTION:
Follow all recommendations, instructions and precautions in this Installation,
Operation and Maintenance Manual to maximize performance, maintain
efficiency and to provide a safe operational environment. Do not install, use
or operate this equipment until this manual has been completely read and
understood.
Important Note:Disconnect electrical power to the furnace and humidifier
before servicing or starting installation.
Liability:
Carnes does not accept any liability for installations of humidifier
equipment installed by unqualified personnel, or the use of parts,
components, equipment, or alterations of Carnes manufactured equipment
that is not authorized or approved by Carnes.
!

COMMERCIAL HUMIDISTAT | Table of Contents
Form 16767 3
Models HXHAS, HXHAST, HXHAW, HXHAWT ......................................... 0
Caution........................................................................................................ 2
Packing List................................................................................................. 4
Humidistat Function .................................................................................... 5
Complete Installation .................................................................................. 6
Duct Installation.................................................................................... 6
Wall Mount Installation ......................................................................... 7
Outdoor Temperature Sensor .............................................................. 8
Location Outdoors.......................................................................... 9
Location in Outdoor Air Intake ..................................................... 10
Wiring ................................................................................................. 11
Power Connection Wiring (R, C) ................................................. 12
Outdoor Temperature Sensor Wiring (ODT) ............................... 12
Humidifier Control Wiring (H1+)................................................... 12
Modes of Operation .................................................................................. 13
Humidistat Demand Mode.................................................................. 14
High Limit Humidistat ......................................................................... 15
Humidity Sensor ................................................................................. 15
Operation .................................................................................................. 16
Screen and Menu............................................................................... 16
Home Screen ............................................................................... 16
Settings Page............................................................................... 17
Setpoint Adjustment Page ........................................................... 17
Units Option .............................................................................................. 18

Packing List | COMMERCIAL HUMIDISTAT
4 Form 16767
Verify all components were included in the humidistat packaging.
BC
Figure 1: Humidistat Package Components
HXHAW A. Humidistat
E. Drywall Anchors and Screws (2 each)
HXHAWT A. Humidistat
C. Outdoor Air Temperature Sensor
E. Drywall Anchors and Screws (2 each)
HXHAS A. Humidistat
B. Duct Sensor
D. Sheet Metal Screws (3)
E. Drywall Anchors and Screws (2 each)
HXHAST A. Humidistat
B. Duct Sensor
C. Outdoor Air Temperature Sensor
D. Sheet Metal Screws (3)
E. Drywall Anchors and Screws (2 each)
A

COMMERCIAL HUMIDISTAT | Installation
Form 16767 5
Humidistat Function
A humidistat is a device that measures relative humidity and works with
an external controller or humidier to automatically control the humidier to
maintain a desired humidity level throughout the conditioned space.
The Carnes commercial humidistats are capable of controlling a humidier by
ON/OFF or modulating 0-10 VDC control signals. The commercial humidistat
package offers 2 types of installation and multiple modes of operation to t
any humidication need. The two types of installations are wall-mounted
and duct-mounted and are offered in differing packages upon ordering. The
multiple modes of operation are the industry standard humidistat demand
output, the high limit demand output, and the humidity sensor output.
Each type of the commercial humidistat will be shipped with different
defaults, all listed below…
Humidistat Version Output (Default) Mode (Default)
HXHAS Modulating 0-10 VDC Common Demand Signal
HXHAST Modulating 0-10 VDC Common Demand Signal
HXHAW Modulating 0-10 VDC High Limit Demand Signal
HXHAWT Modulating 0-10 VDC High Limit Demand Signal

Duct Mounted Installation
1. Choose a location in the duct that
is downstream of the humidier
steam distribution unit. Make sure
the humidistat mounting location is
close enough to plug in the sensor.
Install the sensor a minimum
of 6” ahead of or a minimum
15” after a change in air ow
direction or obstruction in the
duct. Do not install duct sensor
near outdoor air intake.
2. Drill a 1/2” holes in the duct to
place the sensor. Use a sheet
metal screw (D) to attach the sen-
sor to the duct. Arrows in the duct
mount sensor indicate the direction the air ow should pass over the
sensor for optimal measurements.
3. Mount the humidistat display to a wall or duct in a convenient
location that allows easy adjustment to the settings. To mount the
humidistat, remove the back plate and install with screws (D or E)
through the mounting holes.
4. CAUTION: do not plug or un-plug the duct sensor with power
applied to the humidistat, the humidity sensor will break. Plug the
duct sensor into the humidistat. Pay close attention to the orienta-
tion of the plug or permanent damage will occur to the sensor. See
Figure 3 for proper orientation of the duct sensor plug. Place the
hook of the red plug up and away from the humidistat display board
and push onto the white connector located in the bottom left corner
of the humidistat display board. The wire colors also market on the
circuit board and match the correct orientation of the plug wires.
CAUTION: Turn off power before plugging or un-plugging duct
sensor. Do not plug or un-plug the duct sensor with power applied to the
humidistat, the sensor will break.
Installation | COMMERCIAL HUMIDISTAT
6 Form 16767
Air Flow
Figure 2: Duct Sensor

COMMERCIAL HUMIDISTAT | Installation
Form 16767 7
Figure 3: Duct Sensor Connection
Hook Up Away From
Circuit Board
Wire Colors
Wall Mount Installation
1. Select a location in the space that requires humidity control. Typically,
the humidistat will be placed in a location with reasonable air ow for
accurate environmental measurements.
2. The humidistat should be placed in an area of sufcient air movement
and out of the way of any other temperature or humidity affects. For
example, do not place the humidistat in direct sunlight, near windows,
or near an air register.
3. Once the location is selected, attach the humidistat back cover to the
wall using 2 screws/anchors (E).
Note: The duct sensor is not needed for this installation option.

Installation | COMMERCIAL HUMIDISTAT
8 Form 16767
Outdoor Air
Temperature (°F)
Outdoor Air
Temperature (°C)
Adjusted Maximum
Humidity Setpoint
(RH%)
-30 -34.4 10
-20 -28.9 15
-10 -23.3 20
0 -17.8 25
10 -12.2 30
20 -6.7 35
30 -1.1 40
40 4.4 45
45 7.2 47.5
>45 >7.2 Unadjusted
Table 1: Maximum setpoint based on outdoor air temperature
Outdoor Air Temperature Sensor Installation
When outdoor air temperature is very low, condensation can occur on
windows and other surfaces which may cause damage to the structure. To
minimize this risk, the outdoor air temperature sensor should be installed.
The outdoor air temperature lowers the humidity setpoint to a safe level,
where the indoor relative humidity is too low to condense. The outdoor
temperature compensation control adjusts the maximum humidity setpoint
according to the values shown in Table 1. The humidistat will automatically
detect if the outdoor air temperature sensor is connected and control the
relative humidity setpoint accordingly.

COMMERCIAL HUMIDISTAT | Installation
Form 16767 9
CAUTION: electrical interference can cause erratic system operation.
• Do not route temperature sensor wiring with building power wiring,
next to control contactors, near light dimming circuits, or electric
motors.
• Use shielded cable to reduce interference when rerouting is not
possible.
• Be sure wires have a cable separate from the humidistat cable.
• See Figure 5 for wiring diagram.
Exterior Wall Installation
To mount the Outdoor Temperature Sensor outdoors the signal wire will
need to penetrate an exterior wall. Use the following guidelines for proper
operation of the sensor:
Mount the sensor where:
• there is good air circulation
• wire distance between sensor and humidistat is less than 200 feet
• it can measure true outdoor ambient air temperature
• it is above the expected snow line
Do NOT mount the sensor:
• in direct sun
• where it may be covered by debris, snow, or ice

Installation | COMMERCIAL HUMIDISTAT
10 Form 16767
Figure 4: Outdoor Temperature Sensor in Furnace Intake Pipe
Connect to
Humidistat
(ODT)
Drill Hole in
Pipe & Seal OAT (Outdoor
Air Temperature)
Sensor
2” min.
INSIDE OUTSIDE
Furnace
Fresh Air
Intake
Outdoor Air Intake Duct Installation
Mount the sensor in an outdoor air intake by drilling a ¼ inch hole within 8
inches of outside. Angle the hole towards the outside. Insert the temperature
sensor into the intake pipe until the sensor is at least 2 inches outside the
structure in the intake pipe. Seal the hole and secure the wire so it cannot
be accidentally pulled out.

COMMERCIAL HUMIDISTAT | Installation
Form 16767 11
Wiring
**TURN POWER OFF TO ALL HVAC EQUIPMENT BEFORE WIRING**
Figure 5: Humidistat and High Limit Humidistat Field Wiring

Installation | COMMERCIAL HUMIDISTAT
12 Form 16767
Power Connection Wiring (R, C)
The humidistat controller power connections are R and C and will most
commonly be powered by the 18VDC supply directly from the humidier
control board. Proper R and C wiring is shown in Figure 5.
Outdoor Temperature Sensor Wiring (ODT):
The outdoor temperature sensor wires will connect into the ODT terminals
on the humidistat terminal block as shown in Figure 5.
Humidier Control Wiring (H1+):
The humidier control terminal is labeled on the humidistat terminal block as
H1+. This terminal will need to be wired directly to the humidier as shown in
Figure 5. H1+ on the humidistat will connect to either the ‘HUM’ input or the
‘HI’ input on the humidier control board, depending on the conguration of
the humidistat. The ‘HUM’ input will be used when using the humidistat as a
standard humidistat or humidity sensor and the ‘HI’ input will be used when
using the humidistat as a high limit humidistat.

COMMERCIAL HUMIDISTAT | Installation
Form 16767 13
Figure 6: Humidistat DIP-Switch and Output Setting
Modes
The Carnes universal humidistat will come set up in the pre-designated
conguration but has the ability to change and operate in different
control modes depending on the application. The modes are set by
toggling DIP-switches located on the back of the main humidistat display
board, shown in Figure 6.

Operation | COMMERCIAL HUMIDISTAT
14 Form 16767
Humidistat Demand Mode
In the humidistat demand mode, the humidistat will measure the
relative humidity of the space, compare the measured value with the
setpoint, and output a demand signal to the humidier. The demand
signal in this mode can be either on/off or a modulating 0-10VDC.
When measured humidity is 3%RH above the setpoint, the demand
signal will be zero. When measured humidity reaches 3%RH below the
setpoint the demand signal will be 100%.
The modulating 0-10VDC humidistat output corresponds to the demand with
0VDC at 0% demand and 10VDC at 100% demand. The ON/OFF humidistat
output will turn on at 100% demand and will turn back off at 0% demand.

COMMERCIAL HUMIDISTAT | Operation
Form 16767 15
High Limit Humidistat
In the high limit humidistat mode the humidistat will measure the relative
humidity of the space, compare the measured value with a high-set set-
point, and output a demand signal to the humidier. The demand signal in
this mode can be either ON/OFF or a modulating 0-10VDC signal. If the
measured humidity is greater than the high-set setpoint, the demand signal
will be zero, and if the measured humidity reaches 10% below the setpoint
the demand signal will be 100%. The ON/OFF signal will turn on when the
measured humidity is 10% below the setpoint and will back off when the
measured humidity is greater than the setpoint. The high limit humidistat
typically works in conjunction with a wall humidistat to prevent duct work
from becoming saturated by reducing the humidier output when high-
humidity levels are reached.
Humidity Sensor
In humidity sensor mode the humidistat module will measure the relative hu-
midity of the space and output a 0-10VDC signal corresponding directly with
the measured humidity (0%RH = 0VDC, 100%RH = 10VDC). This mode can
be utilized when the Carnes humidier has been congured to function using
a humidity sensor and not a common humidistat. Utilizing the humidistat and
humidier in this way allows for the user to set the setpoint at the humidier
and not the humidistat. This is the preferred operation for BACnet enabled
humidiers.

Operation | COMMERCIAL HUMIDISTAT
16 Form 16767
Screens and Menu
Home Screen
Figure 7: Humidistat Home Screen
Down Enter Up
Active Sensor
ROOM
The external duct
sensor is unconnected
and the on-board room
sensor is active
DUCT
The external duct
sensor is connected
and active
Outdoor air temperature
sensor is connected and
active, if unconnected,
outdoor temperature
display will be blank.
Measured
Humidity
User Setpoint

COMMERCIAL HUMIDISTAT | Operation
Form 16767 17
Figure 8: Setpoint Adjustment Screen
Settings Page
From the Settings page the user can select and adjust how they would like
their humidistat to operate. Pressing Enter while on the BACK selection will
take the user back to the previous page.
Pressing the Enter button once will bring up a settings screen with user
selectable options. Use the Up/Down buttons to navigate the menu and the
Enter button to select and conrm an option.
Setpoint Adjustment Page
While on the Setpoint Adjustment Page the user can adjust the desired
relative humidity setpoint for the humidied space, shown in Figure 8. The
factory default value of this setting is 45%RH and can be adjusted up or
down depending on the user preference. To save the value press the enter
button again. The new humidity setpoint should now be shown on the main
screen (Figure 7).

Units Option | COMMERCIAL HUMIDISTAT
18 Form 16767
Units Option
The Units option allows the user to select temperature display units in
Fahrenheit or Celsius. Fahrenheit is the default.

COMMERCIAL HUMIDISTAT | Notes
Form 16767 19
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This device complies with part 15 of the FCC Rules. Operation is subject
to the following two conditions: (1) This device may not cause harmful
interference, and (2) this device must accept any interference received,
including interference that may cause undesired operation.
448 S. Main St., PO Box 930040, Verona, WI 53593-0040
Phone: 608\845-6411 |Fax: 608\845-6504 |www.carnes.com