Anden AS150 User manual

READ AND SAVE THESE INSTRUCTIONS
AS150 Steam Humidifier
with Steam Dispersion Unit
Installation, Operation, and Maintenance Manual

ii ANDEN AS150 INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
WARNING
Attention installer
Read this manual before installing, and leave this manual with product owner. This product must be installed by qualified
HVAC and electrical contractors. Installation must be code approved. Improper installation can cause property damage,
severe personal injury, or death as a result of electric shock, burns, or fire.
Anden Technical Support: 800-972-3710
Read all warnings and instructions
Read this manual before performing service or maintenance procedures on any part of the system. Failure to follow all
warnings and instructions could produce the hazardous situations described, resulting in property damage, personal injury,
or death.
Failure to follow the instructions in this manual can cause moisture to accumulate, which can cause bacteria and mold
growth or dripping water into building spaces. Dripping water can cause property damage; bacteria and mold growth can
cause illness.
Hot surfaces and hot water
This steam humidification system has extremely hot surfaces. Water in steam cylinders, steam tubing, and dispersion
assemblies can be as hot as 212 °F (100 °C). Discharged steam is not visible. Contact with hot surfaces, discharged hot
water, or air into which steam has been discharged can cause severe personal injury. To avoid severe burns, follow the
cool-down procedure in this manual before performing service or maintenance procedures on any part of the system.
Disconnect electrical power
Disconnect electrical power before installing supply wiring or performing service or maintenance procedures on any part of
the humidification system. Failure to disconnect electrical power could result in fire, electrical shock, and other hazardous
conditions. These hazardous conditions could cause property damage, personal injury, or death.
Contact with energized circuits can cause property damage, severe personal injury, or death as a result of electrical shock
or fire. Do not remove cabinet doors until electrical power is disconnected.
Follow the shutdown procedure on Page 28 before performing service or maintenance procedures on any part of the
system.
Warnings and cautions
WARNING CAUTION
Indicates a hazardous situation that could result in death or
serious injury if instructions are not followed.
Indicates a hazardous situation that could result in damage to or
destruction of property if instructions are not followed.
WARNINGS AND CAUTIONS

iii
ANDEN AS150 SERIES INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
CAUTION
Follow steam piping recommendations
Controlling condensate flow and collection in an Anden AS150 Series humidifier system is critical to maximize performance.
Failure to follow the steam piping recommendations in this manual can cause system pressure fluctuations and increase cylinder
pressure, steam velocity, and condensate noise.
Hot discharge water
Discharge water can be as hot as 212 °F (100 °C) and can damage some drain plumbing materials not rated for hot drain
water. To prevent such damage, make sure drain water tempering is selected, and supply water is not heated. Do not shut off
supply water to the cylinder before it is drained.
Excessive supply water pressure
Supply water pressure greater than 80 psi (550 kPa) can cause the humidifier to overflow.
WARNING
Electrical shock hazard
If the humidifier starts up responding to a call for humidity during maintenance, severe personal injury or death from
electrical shock could occur. To prevent such start-up, follow the shutdown procedure on Page 28.
Warnings and cautions

iv ANDEN AS150 INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Table of contents
WARNINGS AND CAUTIONS ...................................................ii
PRODUCT OVERVIEW ........................................................2
SPECIFICATIONS .............................................................4
Dimensional drawings, capacities, line currents, and fusing ...........4
Dimensions and weights ...................................5
Dispersion options .......................................6
INSTALLATION ..............................................................7
Selecting a location ......................................7
Mounting ..............................................8
Steam cylinder .........................................10
Piping: ...............................................11
Supply water and drain ................................11
Steam blowers ......................................12
Humidifier wiring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Sensor placement .......................................16
Dispersion: ............................................17
Selecting the steam dispersion unit location ..................17
Steam outlet connections ...............................18
Steam blowers ......................................19
ATTENTION INSTALLER
Original Instructions
Read this manual before installing. Leave
manual with product owner.
Anden Technical Support
800-972-3710
Website:
Documents can be viewed, printed or ordered
from our website, www.anden.com.

1
ANDEN AS150 SERIES INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Table of contents
OPERATION .............................................................. 24
Principle of operation ....................................24
Start-up checklist ........................................26
Model AS150..........................................27
MAINTENANCE ........................................................... 28
Shutdown and cool-down procedures .........................28
Replacing steam cylinder ..................................29
Drain valve............................................30
Troubleshooting ........................................31
Replacement parts .......................................34

2ANDEN AS150 INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Product overview
Note: See detailed installation on Page 10 and principle of operation on Page 24.
The Vapor-logic Installation and Operation
Manual ships with Model AS150 humidifiers.
It is a comprehensive manual. Refer to it
for information about the keypad/display
and Web interface, and for troubleshooting
information.
OM-7661_aa
The AS150 electrode steam humidifier uses heat caused by electrical resistance
in their fill water to boil the fill water into humidification steam. Steam output
and water conductivity are managed via automatic draining and filling. See
Figure 2-1.
Steam to AS150 steam blower
(see dispersion options on Page 8)
Electrodes
Electrical resistance in fill water
Overflow to drain
Supply water connection
Control panel for on-board controller
(see Figure 3-1)
Steam cylinder
High water sensor
Fill hose
Overflow
hose
Cylinder drain
Fill cup
Download Anden literature
Anden product manuals can be
downloaded, printed, and ordered from our
website: www.anden.com
FIGURE 2-1: AS150 SERIES HUMIDIFIER COMPONENTS
PRODUCT OVERVIEW

3
ANDEN AS150 SERIES INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Product overview
SUPPLY WATER
There are benefits and trade-offs to consider when the application allows a
choice between hard and softened water:
Hard water: The benefit of hard water is less frequent draining and filling
than with softened water, which results in better energy and water efficiency
and more consistent steam output. However, cylinder replacement could
be more frequent with hard water, because hard water scale coats the
electrodes. The harder the water, the more frequent the need for a new
cylinder.
Softened water may be used in the AS150 series electrode humidifier.
However, softened water ions stay in solution to much higher concentrations
than hard water ions. The result can be more frequent draining and filling,
which results in less energy and water efficiency, and less consistent steam
output. While softened water can reduce scale build-up in the cylinder, it
can also shorten cylinder electrode life.
CONTROLLER
The Model AS150 humidifier Vapor-logic®controller features menus for all
humidifier functions, with a Web interface for access to all functions via
Ethernet.
* On-off switch for control board — not a safety shut-off to humidifier power wiring.
AS150 Vapor-logic keypad/display
Softkeys for direct
menu access
Navigation buttons
for item selection
Controller on-off switch*
Status display and
menu selection
FIGURE 3-1: AS150 SERIES HUMIDIFIER CONTROL PANEL
Table 3-1:
Supply water guidelines for AS150
series electrode humidifiers
Supply water
conductivity
125* to 1250 μS/cm (roughly
comparable to water hardness
of 10 to 36 grains per gallon).
Chlorides Not limited
pH 6.5 to 8.5
Silica < 15 ppm
Demineralized, deionized, and reverse-
osmosis water cannot be used.
Supply water outside of these guidelines may
void your Anden warranty. Please contact
your Anden Representative or Anden Technical
Support if you need advice.
* For optimal low conductivity operation
enable the Mini Drain feature in your Vapor-
logic controller: Main > Setup > Anden
management > Mini Drain > Enable.

4ANDEN AS150 INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Table 4-1:
Line currents and recommended fusing for Anden AS150 Series humidifiers
Model Nominal steam capacity kW Phase Volts Maximum line current (amps) Recommended fusing (amps)
AS150 lbs/hr kg/h
017 50 22 16.5 3 240 48 60
Notes:
* Fill cup extension is required for the following:
- When developed length of steam tubing is more than 20' (6 m)
and duct static pressure exceeds 2" wc (498 Pa)
• Labeled dimensions: inches (millimeters).
• See mounting dimensions in Figure 8-1.
Model AS150
E
D
Electrical knockout
Top
Bottom
Front
Drain outlet
Electrical
knockouts
Supply water
connection
B
OM-7672_no fill cup
F
A
C
Electrical knockout
Dispersion outlet
E
D
G
Dimensional drawings, capacities, line currents, and fusing
SPECIFICATIONS
FIGURE 4-1: AS150 HUMIDIFIER DIMENSIONAL DRAWINGS

5
ANDEN AS150 SERIES INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Table 5-1:
AS150 Series humidifier dimensions by model number
Dimension Description AS150
inches mm
A Cabinet width 17.7 450
B Cabinet height 24.1 612
C Cabinet depth 11.8 300
D Cabinet back edge to steam/drain outlet centers 6.0 152
E Cabinet left edge to steam/drain outlet centers 6.0 152
F Cabinet back edge to supply water connection center 9.5 241
G Cabinet left edge to supply water connection center 1.0 25
Table 5-2:
AS150 Series humidifier weights by model number
AS150
lbs kg
Shipping weight 50 23
Maximum operating weight 79 36
Dimensions and weights
SPECIFICATIONS

6ANDEN AS150 INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Open space dispersion options in Figure 6-1 are available.
Dispersion options
SPECIFICATIONS
Notes:
• Models AS150 and larger require condensate drain.
• Anden steam blowers (SDU) shipped with fuses to be installed in connected AS150 series humidifiers. North America only
Mounted on top of humidifier
Mounted up to 10' (3 m) away from
humidifier
OM-7670
OM-7698
FIGURE 6-1: AS150 STEAM BLOWERS

7
ANDEN AS150 SERIES INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Selecting a location
HUMIDIFIER
When selecting a location for the humidifier, consider the following:
• Elevation of the installed steam dispersion unit
The required installation location for the steam fan pack is at an elevation
higher than the humidifier.
Before installing a dispersion assembly or interconnecting piping, review all
pitch requirements in the “Dispersion” section of this manual.
• Temperature and relative humidity (RH):
Install humidifier only in locations that meet the following temperature and
RH requirements:
- Maximum ambient temperature: 104 °F (40 °C)
- Minimum ambient temperature: 41 °F (5 °C)
- Maximum ambient humidity: 80% RH (non-condensing)
• Required clearances (see Figure 7-1)
• Electrical connections
Electrical power supply connections are at the lower or upper right rear
corner of the unit.
• Supply water and drain piping connections
Water supply piping and drain connections are at the bottom of the
cabinet. See “Piping” on Page 11.
• Exterior wall insulation
Install the humidifier on an exterior wall only if the wall is properly
insulated.
DISPERSION CONTROL DEVICES
See page 17 for recommended installation locations for the fan pack.
INSTALLATION
Staging multiple humidifiers
Up to four Model AS150 humidifiers can be
staged to operate in sequence. In a sequenced
application, one control input signal is divided
into user-selectable control input signals for
the connected humidifiers. See the Vapor-logic
Installation and Operation Manual for
instructions on staging multiple humidifiers.
16"
(400 mm)
15" (380 mm)
3" (76 mm)
between
units
3"
(76 mm)
36" (914 mm)
front clearance
OM-7664
FIGURE 7-1: AS150 SERIES HUMIDIFIER
RECOMMENDED MINIMUM CLEARANCES

8ANDEN AS150 INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Mounting
OM-7969
A
B
C
D
Table 8-1:
AS150 Series humidifier mounting keyhole dimensions
Dimension inches mm
A 7.1 180
B 3.6 92
C 4.4 112
D 16.3 414
E — —
INSTALLATION
0.390" x 0.719"
(9.9 x 18.3 mm)
dia. keyholes
0.390" (9.9 mm)
dia. holes
FIGURE 8-1: AS150 SERIES HUMIDIFIER MOUNTING KEYHOLE LOCATIONS

9
ANDEN AS150 SERIES INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
INSTALLATION
Unpack the humidifier from the shipping carton, and remove the cabinet doors
and steam cylinder (see removing steam cylinder instructions below).
Note: When first unpacking the humidifier, cut and remove the shipping strap
that goes around the cylinder and through the cylinder guides. This strap
does not need to be replaced.
REMOVING STEAM CYLINDER
If sent to this page from the “Maintenance” section, and the humidifier has
been operating, make sure the cylinder is empty and cooled before removing
it. See the shutdown and cool-down procedures on Page 28.
1. Carefully pull the electrode plugs straight up off the cylinder to ensure no
damage to the plug boot occurs.
2. Disconnect the high water sensor wire.
3. Place hands palms-down below cylinder on both sides of drain outlet.
4. Press up against bottom of cylinder with backs of hands while pressing
down against cabinet floor with fingers.
5. Raise cylinder until drain outlet clears drain valve body and the side tabs
on the cylinder have cleared the cylinder guides. Remove cylinder from
cabinet.
WALL MOUNTING HUMIDIFIER
Mount the humidifier level and plumb using the lag bolts provided. Follow the
instructions below for mounting on a wood stud wall.
1. Mount spanner boards on wall, spanning at least two studs. Position one
board at top of cabinet (for the lag bolts), and other board at bottom of
cabinet.
2. Predrill pilot holes in spanner boards, and secure humidifier to spanner
boards with lag bolts.
Note: Use the appropriate mounting methods and mounting hardware for other
wall types.
Mounting
WARNING
Mounting hazard
Mount humidifier per the instructions
in this manual and to a structurally
stable surface. Improper mounting of
the humidifier can cause it to fall or tip,
resulting in severe personal injury or
death.

10 ANDEN AS150 INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
INSTALLATION
OM-7972-XT
Drain valve
body
Cylinder
guide
INSTALLING STEAM CYLINDER
1. Make sure strainer is pressed into steam cylinder drain outlet and strainer
flange is flush with bottom of cylinder outlet. See Figure 10-1.
2. Use water to lubricate drain outlet on bottom of cylinder and O-ring in
drain valve body. See Figure 10-1.
3. Slide steam hose that connects to cylinder and steam blower up until it is
engaged on steam inlet of steam blower and tight against bottom of steam
blower.
4. Slide steam outlet of new cylinder all the way up into open end of steam
hose from Step 3.
5. With Warning label on cylinder facing you, lower cylinder drain outlet into
drain valve body, and rotate cylinder so side tabs line up with cylinder
guides inside cabinet. Push down on cylinder until drain outlet is fully
seated in drain valve body.
6. Slide steam hose down so it is fully engaged on cylinder steam outlet.
Re-install hose clamp(s).
7. Connect high water sensor (yellow) wire to single pin surrounded by
plastic shoulder on cylinder.
8. Connect electrode wires to pins on top of cylinder. Make sure all plugs fit
snugly and are fully engaged on pins.
Important: Three phase cylinders have color-coded dots on the cylinder
and color bands on the electrode plugs. When connecting the plugs, match
the band colors on the plugs with the dot colors on the cylinder. Refer to the
wiring diagram shipped with the humidifier if necessary.
Steam cylinder
OM-7632
Strainer
High water
sensor pin
Warning
label
FIGURE 10-1: STEAM CYLINDER
INSTALLATION
CAUTION
If cylinder plugs become loose, damage to the humidifier may occur. Obtain
replacement plugs from Anden. See “Replacement parts” on Page 35 for part
numbers.

11
ANDEN AS150 SERIES INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
INSTALLATION
Piping:
OM-7591
* Ships with humidifier
• Dashed lines indicate provided by installer
• The open drain must be at least 12”
(300 mm) below the bottom of the
AS150 humidifier, to help prevent steam
condensation on the humidifier.
Important: Thoroughly flush supply
water piping to remove pipe residue and
stagnant water before connecting piping to
humidifier. Pipe residue and stagnant water
in water supply piping can cause foaming,
preventing humidifier from reaching required
steam capacity.
WARNING
Hot drain pipes
Drain piping surface may be hot.
Touching or contact with hot pipe may
cause severe personal injury.
Drain hose*
3/4" (DN20) I.D.
Open drain
1" (25 mm)
air gap
Pitch 1/8"/ft (1%)
toward drain
Hose clamp*
To drain
SUPPLY WATER PIPING
Use only copper for supply water piping; do not use rubber or plastic. The
standard supply water connection before the fill valve is a 1/4" FIP.
In cases where water hammer may be a possibility, consider installing a shock
arrestor. Water pressure must be 25 to 80 psi (175 to 550 kPa).
DRAIN PIPING
Drain piping must be code-approved, 3/4" (DN 20) ID material rated for
212 °F (100°C) minimum.
The drain cup has an integral grounding plate and requires a field-installed
1" (25 mm) air gap to a drain funnel to prevent conduction of electricity in the
drain line.
The AS150 Series humidifier features user-selectable drain water tempering.
When drain water tempering is selected, the humidifier tempers drain water
by opening the fill valve whenever the drain valve is energized to cool drain
water before it enters the drain. Drain water tempering keeps water entering
the drain line less than 140°F (60°C). Manually energizing the drain valve
when the supply water is shut off can allow 212 °F (100 °C) water to enter the
drain line.
Observe the following precautions when selecting and installing drain piping
to ensure personal safety and material integrity:
• When using copper or other metallic drain piping, ground the drain piping
to the earth ground lug in the AS150 Series humidifier.
• Chlorinated polyvinyl chloride (CPVC) piping is a non-metallic alternative
for drain piping. It is rated up to 212°F (100°C) for intermittent-use, low-
pressure applications.
The connection size for the steam cylinder drain is 1" (DN25) hose. Do not
reduce this connection size. If drainage by gravity is not possible, use a
reservoir pump rated for 212 °F (100 °C) water.
The open drain must be at least 12” (300 mm) below the bottom of the AS150
humidifier, to help prevent steam condensation on the humidifier. Use the 12”
(300 mm) drain hose provided and position above field-installed open drain.
Alternately, route drain line away from beneath humidifier to open drain. See
Figure 11-1.
AUTOMATIC DRAIN WATER TEMPERING
AS150 Series humidifiers are shipped with drain water tempering set to ON.
FIGURE 11-1: DRAIN PIPING DETAIL
Supply water and drain

12 ANDEN AS150 INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
INSTALLATION
Piping:
Plastic tie
Condensate hose (purchased
separately from Anden)
Plastic tie
Hose clamp (provided)
Steam hose (not
provided)
Hose clamp (provided)
To open drain or humidifier fill cup.
Water seal is required, whether condensate is piped to
open drain or returned to humidifier fill cup.
OM-7974
7” (178 mm) water seal
Notes:
• Maximum recommended distance between humidifier
and AS150 steam blower is 10’ (3 m).
Steam blowers
FIGURE 12-1: PIPING FROM AS150 SERIES HUMIDIFIER TO REMOTE AS150 STEAM BLOWER

13
ANDEN AS150 SERIES INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
INSTALLATION
Hose clamp (provided)
Hose clamp (provided)
Steam hose (provided)
OM-7976
Notes:
• Maximum recommended distance between humidifier and AS150 steam blower is 10’ (3 m).
Piping: AS150 steam blowers
FIGURE 13-1: PIPING FROM AS150 SERIES HUMIDIFIER TO TOP-MOUNTED AS150
STEAM BLOWER

14 ANDEN AS150 INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Humidifier wiring
All wiring must be code approved and in accordance with the unit wiring
diagram. Power supply wiring must be rated for 105 °C. See Figure 14-1
for the humidifier wiring diagram locations.
When selecting a location for installing the humidifier:
• Avoid areas close to sources of electromagnetic emissions such as power
distribution transformers.
• Do not loop power wiring.
• Do not use aluminum wire.
CONDUIT KNOCKOUTS
Conduit and control wiring knockouts are provided on the AS150 Series
humidifier cabinet. See Figure 4-1.
CONTROL COMPONENT PLACEMENT
Follow the guidelines on Page 16 for placing humidistats and transmitters.
CAUTION
Adding conduit connections not recommended
Adding alternate conduit connections is not recommended. If you must make
additional holes in the humidifier cabinet, protect all internal components from
debris, and vacuum out the cabinet when finished. Failure to follow these precautions
can damage sensitive electronic components and void the Anden warranty.
Notes:
• Control wiring and power wiring must be
run in dedicated or separate earthed metal
conduit, cable trays, or trunking.
• Separate the line voltage wiring from low
voltage control circuit wiring when routing
electrical wiring inside the humidifier
cabinet.
• Do not use chassis or safety grounds as
current-carrying commons. Never use a
safety ground as a conductor or neutral to
return circuit current.
• For circuit protection requirements, see
recommended fusing in Table 4-1.
OM-7692
Fused disconnect
Power supply
AS150 Series
humidifier
Wiring
diagram
inside of
humidifier
cabinet
WARNING
Electric shock hazard
Only qualified electrical personnel
should perform field wiring installation
procedures. Improper wiring or contact
with energized circuits may cause
property damage, severe personal
injury, or death as a result of electric
shock and/or fire.
INSTALLATION
FIGURE 14-1: FIELD WIRING
REQUIREMENTS
FIGURE 14-1: WIRING DIAGRAM

15
ANDEN AS150 SERIES INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Humidifier wiring
CONNECTION INSTRUCTIONS
Before connecting power, refer to the wiring diagram or the data plate on the
outside of the cabinet for wire sizing amperage.
For control signal wiring from a humidistat, transmitter, or signal by others, see
the wiring diagrams shipped inside the humidifier.
See “Step 1 – Field wiring” in the Vapor-logic Installation and Operation
Manual for detailed instructions on the following:
• Control input wiring:
See the “Control input” section.
EARTH GROUNDING REQUIREMENTS
A code-approved safety earth grounding system is required. The ground
connection must be made with solid metal-to-metal connections. Ground wire
should be the same size as power wiring.
UNITS WITH STEAM BLOWER
Steam blowers (SDUs) receive power for operation from the AS150 series
humidifier. For North America only: Install 2 fuses in the AS150 unit to
provide power to the steam blower. Fuses are shipped with the steam blower.
Replacements available from Anden.
WARNING
Excessive moisture hazard
Anden strongly recommends installing a
duct airflow proving switch and a duct
high limit humidistat. These devices
prevent a humidifier from making steam
when there is low airflow in the duct
or when the RH level in the duct is too
high. Failure to install these devices can
result in excessive moisture in the duct,
which can cause bacteria and mold
growth or dripping through the duct.
Proper wiring prevents electrical noise.
Electrical noise can produce undesirable effects
on electronic control circuits, which affects
controllability. Electrical noise is generated
by electrical equipment, such as: inductive
loads, electric motors, solenoid coils, welding
machinery, or fluorescent light circuits. The
electrical noise or interference generated from
these sources (and the effect on controllers)
is difficult to define, but the most common
symptoms are erratic control or intermittent
operational problems.
Important:
• Connect the drain wire to the shield/
screen ground terminal with wire less than
2" (50 mm) in length.
• Do not ground shield at the device end.
INSTALLATION

16 ANDEN AS150 INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
INSTALLATION
Sensor placement
HUMIDISTAT AND SENSOR LOCATIONS ARE CRITICAL
Humidistat and sensor location have a significant impact on humidifier
performance. In most cases, do not interchange duct and room humidity
devices. Room humidity devices are calibrated with zero or little airflow;
whereas duct humidity devices require air passing across them.
Recommended sensor locations (see Figure 16):
A Ideal. Ensures the best uniform mix of dry and moist air with stable
temperature control if HVAC is running constantly.
B Ideal. Mounted centrally above the canopy in an area shielded from water,
light and heat sources
C Acceptable (behind wall or partition) for sampling entire room if sensor is
near an air exhaust return outlet. Typical placement for sampling a critical
area.
D Not acceptable. These locations may not represent actual overall conditions
in the space.
E Not acceptable. Do not place sensors near windows, door passageways,
or areas of stagnant airflow.
Other factors affecting humidity control
Humidity control involves more than the
controller’s ability to control the system. Other
factors that play an important role in overall
system control are:
• Size of humidification system relative to
load
• Overall system dynamics associated with
moisture migration time lags
• Accuracy of humidistats and humidity
transmitters and their location
• Dry bulb temperature accuracy in space
or duct
• Velocities and airflow patterns in ducts
and space environments
• Electrical noise or interference
Outside air
Relief air Return air Air handling
unit
Window
Doorway
Window
Damper control
A
D
E
C
B
D E
E
DC-1084
FIGURE 16-1: RECOMMENDED SENSOR LOCATION