Aprilaire 800 Series Installation and operating instructions

Series 800 Steam Humidifier
Installation & Maintenance Instructions
10010605 B2206277L 09.22
TABLE OF CONTENTS
SAFETY CAUTIONS .............................................. 2
MATERIALS LIST................................................. 3
PRINCIPLES & SEQUENCE OF OPERATION.........................4
SPECIFICATIONS & DIMENSIONS ................................. 5
INSTALLATION INSTRUCTIONS ...................................8
Choosing a Location ........................................... 8
- Dispersion Tube Location ................................... 8
- Elevation .................................................9
- Distance from Humidifier to Dispersion Tube/Fan Pack .......10
- Humidifier Location........................................11
Prepare Humidifier for Mounting ...............................12
Install Steam Dispersion Tube/Fan Pack ........................12
Mount Humidifier.............................................12
Install Steam Hose............................................12
Supply Water ................................................12
Drain Line ...................................................13
Electrical Power Wiring & Shut-off Switch.......................13
Automatic Digital Control & Accessory Wiring ...................18
Thermostat in a Zoned HVAC System...........................19
Manual Digital Humidistat & Fan Pack Wiring ...................20
Automatic Digital Modulating Control Wiring....................21
START-UP PROCEDURE ......................................... 23
OPERATING MODES ............................................24
SHUT DOWN PROCEDURE ......................................25
DISPLAY PANEL ................................................25
MAINTENANCE.................................................26
TROUBLESHOOTING GUIDE .....................................
28
REPLACEMENT PARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
READ AND SAVE THESE INSTRUCTIONS
English 1
30
10016603 B2210091A 09.22

SAFETY CAUTIONS
CAUTION
ATTENTION INSTALLER
Read this manual before installing. This product must be installed by qualified HVAC and electrical contractors and in compliance with local,
state, federal, and governing codes. Improper installation can cause property damage, severe personal injury, or death as a result of electric
shock, burns, or fire.
READ ALL CAUTIONS AND INSTRUCTIONS
Read this manual before performing service or maintenance procedures on any part of the system. Failure to follow all cautions 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 damage to structure and furnishings.
HOT SURFACES AND HOT WATER
This steam humidification system has extremely hot surfaces. Water in steam canister, steam pipes, and dispersion tube 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 procedures in this manual when 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
access panels unless electrical power is disconnected.
Follow the shutdown procedure in this manual before performing service or maintenance procedures on any part of the system.
ELECTRICAL SHOCK HAZARD
If the humidifier starts up responding to a call for humidity during maintenance, severe injury or death from electrical shock could occur. Follow
the procedures in this manual before performing service or maintenance procedures on this humidifier.
EXCESSIVE SUPPLY WATER PRESSURE
Supply water pressure greater than 120 psi may cause the humidifier to overflow.
SHARP EDGES
Sharp edges may cause serious injury from cuts. Use care when cutting plenum openings and handling ductwork.
EXCESS HUMIDITY
Do not set humidity higher than recommended. Condensation may cause damage to structure and furnishings.
2 English

MATERIALS LIST
MODEL 800/800LC
MATERIALS FURNISHED
Humidifier
Model 62 Automatic Digital Humidifier Control
Dispersion tube
Steam hose (6 feet)
7/8" I.D. drain tubing (10 feet)
Hose clamps
Saddle valve
Mounting screws
NOT FURNISHED
Main power disconnect switch
Wiring
1/4" O.D. supply water tubing
Boards for mounting (if required)
MODEL 801
MATERIALS FURNISHED
Humidifier
Dispersion tube
Steam hose (6 feet)
7/8" I.D. drain tubing (10 feet)
Hose clamps
Saddle Valve
Mounting Screws
NOT FURNISHED
Model 63 Automatic Digital Modulating Control
Main power disconnect switch
Wiring
1/4" O.D. supply water tubing
Boards for mounting (if required)
English 3

PRINCIPLES & SEQUENCE OF OPERATION
The Aprilaire® Steam Humidifier delivers humidity in the
form of steam to the conditioned space via the HVAC
system duct or the Fan Pack. The humidifier generates
steam by energizing two electrodes that extend into a
canister of water. Current flowing between the electrodes
causes the water to boil, creating steam. Water is
introduced to the humidifier through a fill valve to a fill
cup located in the top of the cabinet. The fill cup serves
as an overflow reservoir and provides an air gap between
the humidifier and water source. The steam canister is
filled from the bottom. The canister is seated in a drain
cup assembly which includes a drain valve. The drain and
fill valves work together to maintain water level in the
canister to deliver the rated steam capacity based on the
electrical conductivity of the water and to temper drain
water. See FIGURE 1 for representation of fill and drain
system and canister.
To control the Steam Humidifier as part of the HVAC
system, the Model 62 Automatic Digital Humidifier Control
(ADHC) is installed to detect the RH level in the duct.
When the ADHC detects RH below the set point, and the
humidifier and HVAC system blower are operating, the
humidifier energizes the electrodes to provide steam.
Steam is delivered into the duct work via the steam hose
and through the dispersion tube. The dispersion tube
is fitted with “Tubelets™.” The design of the dispersion tube and Tubelets distribute steam over a wide area in the duct and direct any condensed
moisture back into the steam hose. The blower activation function on the ADHC allows the control to turn on the HVAC system blower to maintain the
proper RH level even when the furnace or air handler is in stand-by mode. See ADHC installation manual.
Humidity can be distributed directly into the living space via the Fan Pack. When the Model 65 Manual Digital Humidistat detects RH below the set
point, the humidifier energizes the electrodes to provide steam via the steam manifold at the bottom of the Fan Pack. Steam is dispersed by the fan
located behind the grille above the steam manifold. The fan will operate for two minutes after the call for humidity ends, to disperse any residual steam.
To provide precise control to the Modulating Steam
Humidifier, the Automatic Digital Modulating Control
(ADMC) should be installed in the living space. The ADMC
will vary the Modulating Steam Humidifier output based
on the difference between set point and actual RH. The
ADMC sends a proportional signal to the Modulating
Steam Humidifier providing precise control of living space
humidity. See FIGURE 2 for Steam Humidifier output vs
RH demand. The ADMC can be used in place of the ADHC
and Manual Digital Humidistat to provide On/Off control to
the Steam Humidifier not equipped with the modulating
feature. See the ADMC installation and operating manual
for details.
STEAM HOSE
DISPERSION
TUBE
IN DUCT
TUBELETS
STEAM
OUTLET
DRAIN
SUPPLY
WATER
DRAIN CUP
DRAIN VALVE
CANISTER
ELECTRODES
HIGH WATER LEVEL SENSOR
INLET
FILL VALVE
OVERFLOW
FILL
-2% -5% -10%
20%
100%
HUMIDIFIER OFF
PROPORTIONAL BAND
RH DIFFERENCE FROM SETPOINT (%)
HUMIDIFIER OUTPUT (%)
2% PROPORTIONAL BAND SETTING
5% PROPORTIONAL BAND SETTING (DEFAULT)
10% PROPORTIONAL BAND SETTING
90-1522
90-2008
FIGURE 1 – FILL AND DRAIN SYSTEM AND CANISTER
FIGURE 2 – HUMIDIFIER OUTPUT FOR ADMC SIGNAL
4 English

SPECIFICATIONS & DIMENSIONS
This humidifier is able to produce steam at various capacities depending on the voltage and current applied. The unit can be wired to use an input
voltage of 120, 208 or 240 Volts and input amperage can be set to 11.5 or 16.0 amps by changing a dip switch on the control circuit board (see
the ELECTRICAL POWER WIRING & SHUT OFF SWITCH section on page 13). Configure the unit appropriately for the application (see TABLE 1 for
capacity specifications).
TABLE 1 – HUMIDIFIER CAPACITIES AND RECOMMENDED HOME SIZES
Amperage Voltage
Maximum steam capacity
(gal/day)
Maximum recommended home size in ft2*
Tight Average Loose
11.5
120V 11.5 2,500 sq ft 1,500 sq ft 1,000 sq ft
208V 20.5 4,500 sq ft 2,500 sq ft 1,500 sq ft
240V 23.3
16.0
120V 16.0 3,500 sq ft 2,000 sq ft 1,500 sq ft
208V 30.0 6,000 sq ft 4,000 sq ft 2,500 sq ft
240V 34.6
* Assumes 8 ft ceiling height, adjust as necessary for higher ceilings. For homes with multiple furnaces/air handlers a humidifier should be installed on each.
Model 800 Series Shipping Weight: 28 lbs
Model 865 Shipping Weight: 39 lbs
Humidifier Operating Weight: 23 lbs**
** As minerals precipitate, unit weight can increase to approximately 30 lbs.
English 5

10-1/8
20-7/8
FRONT VIEW
3-3/8
7-7/8
8-7/8
3-3/8
1-5/8
4-1/4 5-3/4
DISPERSION OUTLET
ELECTRICAL KNOCKOUTS
FILL CUP
TOP VIEW
7-1/8
SIDE VIEW
1
4
4
12
BACK VIEW
MOUNTING
HOLES
3-3/8
3-3/8
7-7/8
2
6-5/8
9-1/8
1-7/8
WATER
FILL LINE
CONNECTION
DRAIN
BOTTOM VIEW
ELECTRICAL
KNOCKOUTS
3 SQ
2 SQ
1-3/4
8-1/4
1 DIA
90-1518
FIGURE 3 – HUMIDIFIER DIMENSIONS (INCHES) STEAM DISPERSION TUBE
90-1518
6 English

WATER QUALITY
Minerals that are naturally found in water contribute to water’s electrical conductivity; water conductivity is measured in microsiemens per centimeter
(uS/cm). Mineral content, also described as “water hardness” is usually measured in grains per gallon. Variation is found among water samples but
generally the higher the mineral content, the higher the conductivity.
The Steam Humidifier is designed to operate on water with conductivity between 100 and 1,250 uS/cm. This correlates loosely with water hardness
between 3 and 36 grains/gallon. Water that is considered “hard” and softened water work well in the Steam Humidifier. The humidifier makes steam
when plumbed to low-conductivity water but it takes longer to reach nominal current.
Two canisters are available for use with the Steam Humidifier. The Model 80 canister is used in most installations and is optimized for “hard” and
softened water. The Model 80 typically works best when the Steam Humidifier is installed at 208 or 240 VAC. If the Steam Humidifier has a yellow
Steam light in the first two weeks of running with a new canister, the Steam Humidifier is taking a long time to reach its nominal current; changing to
the Model 80LC canister will prevent this from happening in the future.
The Model 80LC canister is optimized for use in areas where the water conductivity is less than 300 uS/cm or when the Steam Humidifier is installed
at 120VAC. The Model 80LC should not be used with softened water. If the Steam Humidifier is draining too frequently, the water conductivity is too
high; changing to the Model 80 canister will reduce the drain frequency.
As water in the canister boils and turns into steam, minerals are left behind. Minerals remaining in solution increase the conductivity of the water.
Minerals also deposit onto the submerged portions of the electrodes rendering those areas ineffective. As this occurs, the level of water in the canister
rises to expose uncoated electrode surface.
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 soft water, which results in better energy and water efficiency
and more consistent steam output. However, canister replacement could be more frequent with hard water, because mineral deposits coat the
electrodes. The harder the water, the more frequent the need for a new canister.
SOFTENED WATER: The benefit of softened water is longer canister life (depending on water chemistry) than with hard water, because softened
water does not coat the electrodes nearly as much as hard water. However, softened water ions stay in solution to much higher concentrations
than hard water ions. This requires more frequent draining and filling, which results in lower energy efficiency, higher water consumption and less
consistent steam output.
TABLE 2 – WATER QUALITY GUIDELINES
Conductivity
(uS/cm) Grains/Gal Hardness
Recommended Canister by Voltage
120VAC 208VAC 240VAC
75-100 0-3 Naturally Soft Installation Not
Recommended 80LC 80LC
100-300 3-9 Naturally Soft 80LC 80LC 80LC
300-500 9-15 Slightly Hard 80LC 80 80
500-650 15-20 Moderately Hard 80LC 80 80
650-850 20-25 Hard 80LC 80 80
850-1250 25-36 Very Hard 80LC 80 80
above 1250 above 36 Extremely Hard Installation Not Recommended
Softened 80 80 80
English 7

INSTALLATION INSTRUCTIONS
CAUTION
Each humidifier requires its own steam hose and dispersion tube. Do not connect steam hoses from more than one humidifier together. Back-
pressure from one humidifier can lower the water level in the canister in the other humidifier and cause operational problems.
Do not install the dispersion tube in a duct with greater than 2 in. wg static pressure. High duct pressure can cause back-pressure in the canister
which can result in unstable unit operation.
Do not mount humidifier in a location where operating ambient temperatures exceed 140°F or where freezing temperatures may occur.
CHOOSING A LOCATION
DISPERSION TUBE LOCATION
When choosing a location for the dispersion tube three things must be considered: Location in duct, elevation with respect to the humidifier, and
distance from humidifier to dispersion tube.
Duct Location and Absorption Distance
Absorption distance, the unobstructed straight line distance needed for steam to be fully absorbed, is dependent on air velocity, air temperature and
relative humidity in the duct. Determine absorption distance based on the lowest duct temperature, lowest air velocity and highest humidity that
the system will see. The dispersion tube must be located in a straight section of duct far enough upstream of any obstructions or bends in the duct.
Use TABLE 3 to determine the appropriate absorption distance.
Operation during AC calls is not recommended because of the potential for condensation in the ductwork. Configure controls to lock out the
humidifier during AC calls and use the blower activation feature on the ADHC to allow the humidifier to run with the blower only. Call Aprilaire Tech
Support at 1-800-334-6011 for additional information on steam absorption.
The dispersion tube must be mounted with the plate on a vertical surface with the tube angled up as shown in FIGURE 4. The steam tubelets must
face up regardless of the airflow direction in the duct. The plate is labeled “UP” to indicate proper orientation. On horizontal duct runs install the
dispersion tube low in the duct, on vertical runs center the tube on the duct.
If the dispersion tube is mounted on insulated ductwork, make sure insulation is not more than 2" thick at tube location to prevent insulation from
blocking first steam outlet.
NOTE: If dispersion tubes for two humidifiers are installed in one duct, double the dispersion distances. If three dispersion tubes are installed, triple
the dispersion distance. Position dispersion tubes so one does not discharge directly onto another.
8 English

ELEVATION
The preferred location for the dispersion tube is higher than the
humidifier so that the steam hose has a constant downward slope of at
least 2" per foot from the dispersion tube to the humidifier. If hard pipe
is used, the slope can be 1/4" per foot. With the constant downward
slope, any condensation that forms in the steam hose will drain back
into the steam canister. See FIGURE 4.
TABLE 3 – ABSORPTION DISTANCE (MINIMUM DISTANCE FROM DISPERSION TUBE DOWNSTREAM TO ANY OBSTRUCTION OR BEND IN DUCT)
Humidifier Output
(gal/day) Airflow Velocity* 70°F & 30% RH Setpoint 70°F & 45% RH Setpoint 65°F & 45% RH Setpoint 45°F & 45% RH Setpoint
Up to 16.0
300 fpm 13" 19" 23" 30"
600 fpm 6" 10" 12" 18"
1200 fpm 3" 5" 6" 13"
1800 fpm 2" 3" 4" 10"
20.5 – 25.0
300 fpm 15" 23" 28" 45"
600 fpm 6" 12" 13" 26"
1200 fpm 5" 6" 7" 19"
1800 fpm 3" 4" 5" 16"
25.0 – 35.0
300 fpm 24" 31" 36" 60"
600 fpm 17" 22" 26" 48"
1200 fpm 12" 15" 18" 25"
1800 fpm 10" 13" 15" 20"
*Velocity in feet per minute = Duct airflow volume in cubic feet per minute / duct area in square feet.
Example: 1,200 cfm through 16" x 12" duct = 1,200/(12 x 16/144 sq. in./sq ft.) = 1,200/1.333 = 900 fpm
90° LONG SWEEP
OR TWO 45° ELBOWS
PITCH*
DUCT
DISPERSION
TUBE
5" MINIMUM
STEAM HOSE OR PIPE.
INSULATE PIPE WITH
1" FIBERGLASS TO
REDUCE STEAM LOSS.
* PITCH STEAM HOSE DOWN
FROM DISPERSION TUBE TO
HUMIDIFIER:
2"/ FT (15%) MINIMUM
WHEN USING STEAM HOSE.
1/4"/ FT WHEN USING
HARD PIPE.
90-1521
FIGURE 4 – DISPERSION TUBE MOUNTED ABOVE HUMIDIFIER
English 9

NOTICE
CONTROL CONDENSATE FLOW AND COLLECTION.
Failure to follow steam hose recommendations in this manual
can result in reduced or erratic performance, increased noise and
condensate in the duct.
If the dispersion tube must be mounted below the humidifier or if the
steam hose needs to run up and over an obstruction, a drip tee with
drain trap, Part #4028, must be installed as shown in FIGURE 5. When
using the Fan Pack, install Part #4028 close to the humidifier outlet to
help prevent noise from gurgling as shown in FIGURE 6.
DISTANCE FROM HUMIDIFIER TO DISPERSION TUBE/FAN PACK
The capacity of the humidifier is reduced by the length of the steam
hose or pipe due to condensation. The maximum recommended length
of steam hose is 6 feet. Use hard pipe insulated with 1" thick insulation
rated for 212°F or higher for lengths greater than 6 feet. TABLE 4
provides humidifier capacity with various lengths of steam hose and
pipe. If 6-foot steam hose does not reach from humidifier to dispersion
tube, splice in 1" copper pipe using 3/4" x 1" reducing couplings as
shown in FIGURE7.
PITCH
OBSTRUCTION
90° LONG
SWEEP OR TWO
45° ELBOWS
6" MIN
8" MIN
INSULATE HARD PIPE TO
REDUCE STEAM LOSS
1" AIR GAP
OPEN DRAIN REQUIRED,
SEE NOTE 1.
NOTES:
1. REFER TO GOVERNING CODES
FOR DRAIN PIPE SIZE AND
MATERIALS.
2. SUPPORT STEAM HOSE SO THERE
ARE NO SAGS OR LOW SPOTS.
DRIP TEE
DRAIN TRAP
PART #4028
TO DISPERSION
TUBE/FAN PACK
DRIP TEE INSTALLATION FOR PIPING OVER OBSTRUCTION,
OR IF DISPERSION TUBE IS LOWER THAN HUMIDIFIER.
#4028 KIT
CONTENTS:
HOSE CLAMPS (5)
TRAP (1)
TEE ASSEMBLY (1)
TEE ASSEMBLY
FLARED END
TRAP
NOTE: PRIME WITH WATER
BEFORE USING HUMIDIFIER
HOSE CLAMP
HOSE
CLAMP
HOSE CLAMP
TO STEAM
DISPERSION
TUBE OR
FAN PACK
STEAM
HOSE
1" I.D.
STEAM HOSE, 1" I.D.
(DOWNWARD SLOPE TO TEE)
DRAIN HOSE
7/8" I.D.
STEAM HOSE
1" I.D.
(DOWNWARD
SLOPE FROM
HUMIDIFIER
TO TEE)
HOSE CLAMP
STEAM
HUMIDIFIER
90-1520
90-1844
FIGURE 5 – DISPERSION TUBE MOUNTED BELOW HUMIDIFIER
STEAM HOSE
STEAM HOSE
1-1/2" HOSE CLAMP
1-1/2" HOSE CLAMP
1" COPPER PIPE
3/4" X 1"
REDUCING
COUPLING
HUMIDIFIER
TO STEAM
DISPERSION
TUBE OR
FAN PACK
90-1527
FIGURE 7
FIGURE 6
10 English

TABLE 4 – STEAM HUMIDIFIER CAPACITY IN GALLONS/DAY
Steam
Hose or
Insulated
Pipe
Length
120 Volts 208 Volts 240 Volts
11.5 Amps 16.0 Amps 11.5 Amps 16.0 Amps 11.5 Amps 16.0 Amps
Steam
Hose
Insulated
Pipe
Steam
Hose
Insulated
Pipe
Steam
Hose
Insulated
Pipe
Steam
Hose
Insulated
Pipe
Steam
Hose
Insulated
Pipe
Steam
Hose
Insulated
Pipe
< 2 ft. 11.5 11.5 16.0 16.0 20.5 20.5 30.0 30.0 23.3 23.3 34.6 34.6
2 ft. 11 11 15.5 15.5 20 20 29 29.5 23 23 34 34
4 ft. 10 11 14.5 15.5 19 20 28 29.5 22 23 33 34
6 ft. 9 11 13.5 15 18 20 27 29 21 22 32 33
8 ft. 10 14 19 28 22 33
10 ft. 10 14 19 28 22 33
12 ft. 10 14 19 28 22 33
14 ft. 9 13 18 27 21 32
16 ft. 9 13 18 27 21 32
18 ft. 9 13 18 27 21 32
20 ft. 9 13 18 27 20 31
HUMIDIFIER LOCATION
Do not mount humidifier in a location where operating ambient
temperature exceeds 140°F or where freezing temperatures may
occur. Extreme temperatures may cause the humidifier to leak which
can damage furnishings or structure.
Mount humidifier in a location that allows access for servicing, and
clearance to remove front panel for replacing the canister and side
panel for access to the electrical components during installation. See
FIGURE 8 for minimum clearances around humidifier.
The humidifier should be mounted as close to the dispersion tube
as possible. TABLE 4 shows how capacity is reduced as the distance
between the humidifier and dispersion tube increases. If the humidifier
is mounted on the duct directly below the dispersion tube, allow space
for a bend in the steam hose. Allow a minimum of 2" of steam hose to
extend straight out of the humidifier before beginning any bends; this
will help ensure a tight connection with the top of the canister.
The humidifier can be mounted to a wood surface, or to sheet metal
ductwork if it is structurally stable. Do not mount humidifier to fiber
duct board. Sound isolation may be desired when mounting to sheet
metal ductwork.
The humidifier must be mounted to a vertical surface and must be
mounted level in the upright position.
16" FOR
STEAM
HOSE
30" FOR
SERVICE
ACCESS
16" FOR
ELECTRICAL
ACCESS
4"
16"
FOR DRAIN
FRONT VIEW
SIDE VIEW
90-1519
FIGURE 8 – CLEARANCES
English 11

PREPARE HUMIDIFIER FOR MOUNTING
Unpack carton. Open front panel by removing screw and lifting panel up and away from humidifier. Disconnect three wires from top of canister
by pulling straight up. The two large wires are the electrode conductors. The smaller wire is connected to the high water level sensor. Remove
canister by pulling it up and out of drain assembly. Remove two screws on right side of humidifier and lift side panel off housing to expose electrical
compartment.
INSTALL STEAM DISPERSION TUBE
Make sure steam dispersion tube is mounted higher than the humidifier so that condensation that forms in the steam hose runs back into the canister.
If the dispersion tube cannot be mounted higher than the humidifier or if the steam hose must extend up from the humidifier then down to the
dispersion tube due to an obstruction, a drip tee and drain trap system (Part #4028) must be installed as shown in FIGURE 5.
Drill a 1-1/4" diameter hole in a vertical surface of the duct at the location chosen for the dispersion tube. Position the dispersion tube so it is angled
up, regardless of airflow direction. UP is stamped on the mounting bracket to aid in proper installation. Secure with four sheet metal screws provided.
MOUNT HUMIDIFIER
Secure humidifier to a sturdy wall using screws provided, or to sheet metal duct. Humidifier initially weighs 23 lbs with a full canister, but will increase
in weight over time due to the precipitation of minerals inside the canister. Make sure mounting system will support weight. If mounting to stud frame
wall, install two spanner boards to studs and fasten humidifier to spanner boards. Make sure humidifier is mounted plumb.
INSTALL STEAM HOSE
Six feet of steam hose is provided with the humidifier. If the steam hose must be cut, use a hacksaw. If additional length is required, use 1" O.D. metal
or copper pipe. Do not use PVC pipe for steam line. Insulate pipe with 1" thick insulation rated for 212°F or higher to reduce steam loss. See TABLE 4
for humidifier capacity at various lengths of steam hose and pipe.
Use the steam hose provided. Other hoses may have impurities which can cause foaming in the canister. Foaming can cause water level inaccuracies,
reduced steam production and water sputtering into the duct. When using pipe, remove all traces of residual materials used to connect the pipe to
prevent foaming.
Verify that the O-ring is in place in the groove in the drain assembly. Dampen the O-ring with water (DO NOT use oil, grease,or any lubricant besides
water), then reinsert the canister with the caution label positioned toward the front of the unit.
Attach steam hose to dispersion tube and then to top of canister using hose clamps provided. Make sure steam hose has a constant slope of at least
2" per foot between the dispersion tube and the humidifier. Any and every low spot in the steam hose or pipe must have a drip tee and drain trap. Fill
drain trap with water before making final connections. Support the steam hose in multiple locations over its span to prevent sagging.
Attach and fully seat the electrode conductors (interchangeable) and the high water level sensor wire to the top of the canister.
SUPPLY WATER
Plumb the humidifier to cold, hard or softened water. Do not use hot water because unheated supply water is used to cool water draining from
the humidifier. Do not use demineralized or reverse osmosis water. For proper operation, supply water pressure must be between 25 psi and 120 psi.
Hard or softened water may be used provided it has conductivity between 125 microS/cm and 1250 microS/cm. See TABLE 2.
Supply water piping must be free of oils, lubricants, solder flux and other contaminants, which can cause foaming.
Follow local plumbing codes. An external backflow preventer may be needed.
Install the saddle valve according to the instructions printed on the bag. Run 1/4" copper tubing from the saddle valve to the humidifier. Connect it to
the fill valve. Double wrench to prevent leaking and damage to valve. Addition of a stainless steel braided water line can help reduce valve noise.
NOTE: Adding an inline particulate filter can increase canister life in areas with high levels of suspended solids. DO NOT use filters that release scale
inhibitors, filters of this type can significantly decrease canister life.
12 English

DRAIN LINE
Attach the 7/8" I.D. drain tubing provided to the drain assembly at the bottom of the humidifier. Secure with the hose clamp provided. Do not over
tighten.
Make sure the drain line has a constant downward slope from the humidifier to the drain and is not kinked or blocked.
If floor drain is not available, use condensate pump (Part #4856) to route water to a suitable drain. Provide at least 16 inches for of drain line between
the Steam Humidifier and the condensate pump.
NOTE: The humidifier uses cold water to temper drain water to less than 140°F.
ELECTRICAL POWER WIRING & SHUT-OFF SWITCH
CAUTION
Only qualified electrical personnel should perform field wiring procedures. Improper wiring or contact with energized circuits can cause property
damage or severe personal injury.
All wiring must be installed in accordance with all governing electrical codes and with the wiring diagram provided inside the front panel.
Do not loop power wiring.
Do not use aluminum wire.
A safety grounding system that meets all governing electrical codes is required. The ground connection must be made with solid metal to metal
connections. Ground wire must be the same size as the power wiring.
With factory settings, the Steam Humidifier draws 11.5 amps +/- 10%. Use a minimum 20 amp dedicated circuit when installing to operate at 11.5
amps. The Steam Humidifier can be set to draw 16.0 amps +/- 10% by repositioning dip switch #1 on the control circuit board (see FIGURE9). When
set to 16 amps, use a minimum 25 amp dedicated circuit. For both applications, size wire according to local codes.
The Steam Humidifier is shipped from the factory wired for 240 VAC operation, but it can operate on 120, 208 or 240 VAC. If using 120V or 208V,
move the black/white jumper wire to the proper tab on the control circuit board. See FIGURES 10, 11, 12.
WIRING INSTRUCTIONS
Install disconnect switch (not provided) between line power source and humidifier.
Knock-outs for power wiring and low voltage control circuit wiring are provided.
Connect power and ground wiring as shown in appropriate wiring diagram.
• 240 VAC – FIGURE 10
• 208 VAC – FIGURE 11
• 120 VAC – FIGURE 12
Do not run high voltage power lines over internal circuit boards.
English 13

FACTORY SETTING
FOR 11.5 AMP
NOMINAL OPERATION.
SLIDE DIP SWITCH #1
TO “ON” POSITION
FOR 16.0 AMP
NOMINAL OPERATION.
LED D8
90-1959
FIGURE 9 – CONTROL CIRCUIT BOARD WITH DIP SWITCHES
14 English

L2 / N
L1
GND J8 J10 J16
J2
10
1
J5 J6
P4
P3
CONTROL CIRCUIT WIRING
HIGH VOLTAGE WIRING
HIGH VOLTAGE FIELD WIRING
DRAIN
VALVE
FILL
VALVE
DISPLAY PANEL
RIBBON CABLE
BLK
BLK
YEL
BLK YEL
TRANSFORMER POWER
JUMPER WIRE
BLK/WHT
WHT
RED
BLK
ORG
YEL
BLUE
MAIN POWER BREAKER
(NOT PROVIDED)
TRANSFORMER
J11
120
VAC
J13
208
VAC
J14
240
VAC
LOW VOLTAGE FIELD WIRING
SLOW BLOW FUSE
(5X20mm 5A)
ELECTRODE
WATER LEVEL
PROBE
ELECTRODE
STEAM CANISTER
P7
HUMIDISTAT
1
2
FAN PACK
CON1
STEAM HUMIDIFIER IS
SHIPPED FROM THE FACTORY
WIRED FOR 240 VOLTS.
HUMIDITY CONTROL
(PROVIDED)
FAN PACK
(OPTIONAL)
DOOR SWITCH
ORANGE
DRY
CONTACT
POWER
TERMINAL
BLOCK
90-1903
FIGURE 10 – 240 VAC WIRING DIAGRAM
English 15

J8 J10 J16
J2
10
1
J5 J6
P4
CONTROL CIRCUIT WIRING
HIGH VOLTAGE WIRING
HIGH VOLTAGE FIELD WIRING
BLK
BLK
YEL
YEL
TRANSFORMER POWER
JUMPER WIRE
BLK/WHT
HUMIDITY CONTROL
(PROVIDED)
FAN PACK
(OPTIONAL)
DOOR SWITCH
ORANGE
DRY
CONTACT
YEL
BLUE
TRANSFORMER
J11
120
VAC
J13
208
VAC
J14
240
VAC
ELECTRODE
WATER LEVEL
PROBE
ELECTRODE
STEAM CANISTER
LOW VOLTAGE FIELD WIRING
P7
P3
WHT
RED
BLK
ORG
FAN PACK
HUMIDISTAT
1
2
STEAM HUMIDIFIER IS
SHIPPED FROM THE FACTORY
WIRED FOR 240 VOLTS.
MOVE THE JUMPER WIRE TO
TERMINAL J13 TO OPERATE
AT 208VAC.
MAIN POWER BREAKER
(NOT PROVIDED)
L2 / N
L1
GND
DRAIN
VALVE
FILL
VALVE
DISPLAY PANEL
RIBBON CABLE
BLK
SLOW BLOW FUSE
(5X20mm 5A)
CON1
POWER
TERMINAL
BLOCK
90-1904
FIGURE 11 – 208 VAC WIRING DIAGRAM
16 English

HUMIDITY CONTROL
(PROVIDED)
FAN PACK
(OPTIONAL)
DOOR SWITCH
POWER
TERMINAL
BLOCK J8 J10 J16
J2
10
1
J5 J6
P4
J11
120
VAC
J13
208
VAC
J14
240
VAC
CONTROL CIRCUIT WIRING
HIGH VOLTAGE WIRING
HIGH VOLTAGE FIELD WIRING
ORANGE
BLK
BLK
YEL
TRANSFORMER POWER
JUMPER WIRE
BLK/WHT
YEL
BLUE
TRANSFORMER
LOW VOLTAGE FIELD WIRING
DRY
CONTACT
P7
P3
WHT
RED
BLK
ORG
FAN PACK
HUMIDISTAT
1
2
STEAM HUMIDIFIER IS
SHIPPED FROM THE FACTORY
WIRED FOR 240 VOLTS.
MOVE THE JUMPER WIRE TO
TERMINAL J11 TO OPERATE
AT 120VAC.
MAIN POWER BREAKER
(NOT PROVIDED)
L2 / N
L1
GND
DRAIN
VALVE
FILL
VALVE
DISPLAY PANEL
RIBBON CABLE
BLK YEL
SLOW BLOW FUSE
(5X20mm 5A)
CON1
ELECTRODE
WATER LEVEL
PROBE
ELECTRODE
STEAM CANISTER
90-1905
FIGURE 12 – 120 VAC WIRING DIAGRAM
English 17

AUTOMATIC DIGITAL CONTROL & ACCESSORY WIRING (MODEL 800)
The control circuit operates on 24VAC.
The ADHC (Automatic Digital Humidifier Control) Model 62 must be mounted in the return air duct at least 6" upstream of any fresh air intake ducts
or sources of moisture and at least 12" upstream of the steam dispersion tube if it is mounted in the return. Follow instructions provided with the
control. Connect “H” terminals on ADHC to “HUMIDISTAT” terminals on humidifier circuit board. The “H” terminals on the Model 62 provide a dry
contact switch to energize the humidifier.
If the application requires a wall-mounted humidistat in the conditioned space, use Manual Humidistat Part #4655, Digital Manual Humidistat Part
#65, Automatic Digital Modulating Humidistat Part #63 or any Aprilaire thermostat with integrated humidifier control functionality. Use Blower
Activation Relay Part #4851 with Aprilaire Manual and Digital Manual Humidistats in order to allow the humidifier to turn on the HVAC system blower
when humidity is required.
If protection from over-humidification is desired, install optional high humidity limit switch Part #4594 at least 4 feet downstream of the dispersion
tube. If airflow verification is desired, install optional airflow proving switch Part #4592 in duct. The high humidity limit switch and the airflow proving
switch are wired in series with the ADHC (humidistat) circuit. See FIGURE 13.
24 VAC FROM HVAC
EQUIPMENT “R” & “C”
OUTDOOR TEMPERATURE SENSOR
HEAT SIGNAL FROM HVAC EQUIPMENT
FAN SIGNAL FROM THERMOSTAT OR
ZONE PANEL EQUIPMENT TERMINALS
FAN SIGNAL TO HVAC EQUIPMENT
MODEL 62 DIGITAL HUMIDIFIER CONTROL
24V TERMINALS
OPTIONAL:
AIR FLOW PROVING SWITCH #4592
CONNECT 1/4" PLASTIC TUBING FROM H (HIGH) SIDE OF
PROVING SWITCH TO THE AIRFLOW SENSING PROBE
LOCATED 1.5 DUCT DIAMETERS DOWNSTREAM OF
BLOWER. LEAVE L (LOW) SIDE OPEN TO AMOSPHERE.
OPTIONAL:
HIGH HUMIDITY LIMIT SWITCH #4594
SWITCH BREAKS C TO NO CONNECTION WHEN
MEASURED RH IS ABOVE SETPOINT RH.
HGf R C ODT GW H
FAN PACK HUMIDISTAT
CNO NC
C
NO
NC
90-1544
FIGURE 13– STEAM HUMIDIFIER ACCESSORY WIRING
18 English

R W Y G
NO
C
NO
C
EQUIPMENT
ZONE 1
ZONE 2
12"
MIN
R
C
W
Y
G
R C W G HH GF
ZONE DAMPERS
STEAM DISPERSION TUBE MOUNTED ON THE RETURN DUCT
HIGH HUMIDITY
LIMIT SWITCH
STEAM
DISPERSION
TUBE
MODEL 62
CONTROL
ABSORPTION
DISTANCE
HVAC
FURNACE
MODEL 62 CONTROL
AIR FLOW
PROVNG
SWITCH
HIGH HUMIDITY
LIMIT SWITCH
MODEL 800 HUMIDIFIER
ZONE PANEL
AIR FLOW
PROVING
SWITCH
90-2229
FIGURE 14 – STEAM HUMIDIFIER INSTALLED ON A ZONED HVAC SYSTEM
THERMOSTAT IN A ZONED HVAC SYSTEM
Mount the steam dispersion tube in the return
duct. Each individual zone must be able to
handle the full load from the Steam Humidifier
without condensation issues. Mount the Model
62 ADHC and the air flow proving switch
(recommended) upstream of the dispersion
tube. A high humidity limit switch installed 4
to 5 feet downstream of the dispersion tube is
recommended. Absorption distance must be
calculated for the lowest air velocity (when all
zones are calling) and when smallest zone is
calling (bypass air can decrease the velocity in
the return). Wire humidistat to the equipment
terminals on the zone panel.
English 19

MANUAL DIGITAL HUMIDISTAT & FAN PACK WIRING (MODEL 865)
Mount the Digital Manual Humidistat in the area to be humidified according to installation instructions included with control. Install the humidistat
in the same room or area as the Fan Pack discharge, but at least ten feet away. Wire the Digital Manual Humidistat to the Steam Humidifier using
standard 24 volt thermostat wire. See FIGURE 15.
Disconnect all power to the Steam Humidifier before wiring the Fan Pack terminals to the FAN PACK terminals on the Steam Humidifier. Use standard
24 volt thermostat wire. See FIGURE 15.
H
H
R
C
FAN PACK
HUMIDISTAT
STEAM HUMIDIFIER
FAN PACK
APRILAIRE MODEL 800 STEAM HUMIDIFIER
TRANSFORMER
JUMPER PROVIDED WITH FAN PACK
CIRCUIT
BOARD
WIRE:
18 AWG ACCEPTABLE FOR
24 VAC APPLICATION
MODEL 65 DIGITAL CONTROL
P4
24VAC
24VAC
YELLOW
BLUE
BLUE
YELLOW
WHITE
RED
WHITE
RED
90-2198
FIGURE 15– WIRING DIAGRAM FOR MANUAL HUMIDISTAT AND FAN PACK
20 English