Aprilaire 800 Series Installation and operating instructions

Model 800 Residential Steam Humidifier
TABLE OF CONTENTS
Safety Cautions..........................................2
Materials List ...........................................2
Principles of Operation...................................3
Specifications & Dimensions .............................3
Installation Instructions ..................................5
Choosing a Location .....................................5
- Dispersion Tube......................................5
- Humidifier ..........................................7
Prepare Humidifier for Mounting ...........................8
Install Steam Dispersion Tube .............................8
Mount Humidifier .......................................8
Install Steam Hose ......................................8
Supply Water...........................................8
Drain Line..............................................9
Automatic Digital Control and Control Wiring.................9
Electrical Power Wiring & Shut-off Switch ..................10
Start-up Procedure .....................................14
Sequence of Operation..................................14
Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Shut Down Procedure...................................15
Display Panel ..........................................16
Maintenance...........................................17
Checking System Operation & Troubleshooting ............18
Replacement Parts......................................21
READ AND SAVE THESE INSTRUCTIONS
Model 800 Residential Steam Humidifier
Installation & Maintenance Instructions

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 until 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 bodily 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.
SAFETY CAUTIONS
MATERIALS LIST
MATERIALS FURNISHED NOT FURNISHED
Humidifier
Automatic Digital Humidifier Control
Dispersion tube
Steam hose (6 feet)
Main power disconnect switch
Wiring
1/4” O.D. supply water tubing
Boards for mounting (if required)
7/8” I.D. drain tubing (10 feet)
Hose clamps
Saddle valve
Mounting screws
2

Minerals that are naturally found in water cause the water to
be electrically conductive. Water conductivity is measured in
micro Siemens per centimeter (uS/cm). Mineral content, also
described as “water hardness” is usually measured in grains per gallon. Because of the variety of minerals that are found in water, there is no
direct correlation between water hardness and conductivity, but generally the higher the mineral content, the higher the conductivity.
The Model 800 Canister Steam Humidifier is designed to operate on water with conductivity between 125 and 1,250 uS/cm. This correlates
loosely with water with hardness between 3 and 36 grains/gallon. Water that is considered “hard” and also softened water work well in the
Model 800. The humidifier will make steam when plumbed to low-conductivity water but it takes longer to reach nominal capacity.
With low conductivity water, it may take the Model 800 humidifier one week or more of operation to reach rated capacity,
especially if it is wired to operate on 120 volts. When operating on 240 volts, the Model 800 usually will reach nominal capacity
within a few hours, even with lower conductivity water.
As water in the canister boils and turns into steam, minerals are left behind. The remaining minerals, if they remain in solution in the water,
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.
SPECIFICATIONS & DIMENSIONS
TABLE 1 – Specifications
Voltage kW Maximum steam capacity Nominal Current draw (amps) Humidifier unit operating weight
gal/day amps lbs
120V 1.4 11.5 11.5 23
208V 2.4 20.5 11.5 23
240V 2.8 23.3 11.5 23
The Aprilaire®Model 800 Canister Steam Humidifier delivers
humidity in the form of steam to the conditioned space via
the HVAC system duct or optional Aprilaire Model 850 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.
Steam is delivered into the airstream through a dispersion
tube mounted in the HVAC system ductwork. Openings in the
dispersion tube are fitted with “tubelets” which extend into
the center of the tube. 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.
PRINCIPLES OF OPERATION
FIGURE 1 – Fill and Drain System and Canister
90-1522
Steam
Outlet
Drain
Supply
Water
Drain Cup
Drain Valve
Canister
Electrodes
High Water
Level Sensor
Flow Control
Orifice
Inlet
Fill Valve
Overflow
Fill
Fill Cup
WATER QUALITY
3

FIGURE 2 – Humidifier & Dispersion Tube Dimensions
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"
7 7/8"
2"
3 3/8"
Water Fill Line Connection
Drain
BOTTOM VIEW
3" sq
2" sq
8 1/4"
1" dia
STEAM DISPERSION TUBE
3" Mounting Plate
to first opening
1 3/4"
UP
90-1518
SPECIFICATIONS & DIMENSIONS (CONTINUED)
4

CHOOSING A LOCATION
DISPERSION TUBE
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
The preferred location for the dispersion tube is in a supply duct because higher temperature air will more readily absorb the moisture. Whether
installed in a supply or return, the dispersion tube must be in a straight section of duct to avoid turbulent air and must be far enough upstream
of any obstruction or bends in the duct to allow the steam to be fully absorbed to prevent condensation. The exact distance from obstructions in
the duct depends on air temperature, RH set point, and airflow velocity in the duct. Table 2 provides absorption distance for typical conditions.
The higher the RH setting, the longer the absorption distance. Warmer air shortens the absorption distance. If absorption distance is a concern,
install dispersion tube in supply duct and configure humidifier and control to operate only during HVAC system heat call. When installing the
humidifier in a system with variable speed blower, determine absorption distance based on airflow at the lowest speed. Call Aprilaire Tech
Support at 1-800-334-6011 for additional information on absorption.
The dispersion tube must be mounted with the plate on a vertical surface with the tube angled up as shown in Figure 3. The steam outlets must
face up regardless of the airflow direction in the duct. The plate is labeled “UP” to indicate proper orientation.
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 two dispersion tubes 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.
INSTALLATION INSTRUCTIONS
*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
TABLE 2 – Absorption Distance (Minimum distance from dispersion tube downstream to any obstruction or bend in duct)
Input
Power Humidifier Output Airflow Velocity* 70°F & 30% RH
Setpoint 70°F & 45% RH
Setpoint 65°F & 45% RH Setpoint
120 V 11.5 gal/day
300 fpm 7" 11" 13"
600 fpm 3" 6" 7"
1200 fpm 2" 3" 3"
1800 fpm < 2" 2" 2"
208 V 20.5 gal/day
300 fpm 13" 19" 23"
600 fpm 6" 10" 12"
1200 fpm 3" 5" 6"
1800 fpm 2" 3" 4"
240 V 23.3 gal/day
300 fpm 15" 23" 28"
600 fpm 6" 12" 13"
1200 fpm 5" 6" 7"
1800 fpm 3" 4" 5"
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.
5

TABLE 3 – Steam Humidifier Capacity in Gallons/Day
Steam Hose
or Insulated
Pipe Length
120 Volts 208 Volts 240 Volts
Steam Hose Insulated Pipe Steam Hose Insulated Pipe Steam Hose Insulated Pipe
< 2 ft. 11.5 11.5 20.5 20.5 23.3 23.3
2 ft. 11 11 20 20 23 23
4 ft. 10 11 19 20 22 23
6 ft. 911 18 20 21 22
8 ft. 10 19 22
10 ft. 10 19 22
12 ft. 10 19 22
14 ft. 918 21
16 ft. 918 21
18 ft. 918 21
20 ft. 918 20
Distance from Humidifier to Dispersion Tube
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” fiberglass for lengths greater than 6 feet. Table 3 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
¾” x 1” reducing couplings as shown in Figure 5.
Pitch
Obstruction
90° long sweep
or two 45° elbows
6" min
8" min
Insulate hard pipe to
reduce steam loss
To
Dispersion
Tube
1" air gap
Open drain
required,
see note 1.
Drip tee installation for piping over obstruction,
or if dispersion tube is lower than humidifier.
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
FIGURE 4 – Dispersion Tube Mounted Below Humidifier
90-1520
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 3. 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 4.
FIGURE 3 – Dispersion Tube Mounted Above Humidifier
90-1521
90° long sweep
or two 45° elbows
Pitch*
Duct
Dispersion tube
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.
INSTALLATION INSTRUCTIONS (CONTINUED)
6

HUMIDIFIER
Do not mount humidifier in a location where ambient
temperature exceeds 120°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 6 for minimum clearances around humidifier.
The humidifier should be mounted as close to the dispersion
tube as possible. Table 3 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.
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.
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
FIGURE 6 – Clearances
90-1519
INSTALLATION INSTRUCTIONS (CONTINUED)
FIGURE 5
90-1527
Steam Hose
Dispersion Tube
Steam Hose
1-1/2" Hose Clamp
1-1/2" Hose Clamp
1" Copper Pipe
3/4" x 1" Reducing Coupling
Humidifier
7

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
drained 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.
Supply water piping must be free of oils, lubricants, solder flux and other contaminants, which can cause foaming in the canister that can lead to
water sputtering from the dispersion tube into the duct.
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.
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.
MOUNT HUMIDIFIER
Secure humidifier to sturdy wall using screws provided, or to sheet metal duct. Humidifier weighs 23 lbs. with full 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.
Verify that the O-ring is in place in the slot in the drain assembly. Dampen the O-ring with water, then reinsert canister. (Do not use oil, grease or
any lubricant besides water.) Rotate the canister so the caution label is visible. Reattach the electrode conductors (interchangeable) and the high
water level sensor wire.
INSTALL STEAM DISPERSION TUBE
Note: If humidifier will deliver steam via the Model 850 Fan Pack instead of the dispersion tube, follow instructions included with Fan Pack.
Make sure steam dispersion tube is mounted higher than the humidifier so that condensate that forms in the tube 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 4.
Drill a 1-1/4” diameter hole in a vertical surface of the duct at the location chosen for the dispersion tube. Position the tube so it is angled up,
regardless of airflow direction. Secure with four sheet metal screws provided.
INSTALLATION INSTRUCTIONS (CONTINUED)
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 fiberglass to reduce steam loss. See Table 3 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 and reduced steam production. When using pipe, remove all traces of residual materials used to connect the pipe to prevent foaming.
Attach steam hose to dispersion tube and then to top of canister using hose clamps provided. Use heavy wire clamp to secure hose to canister.
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.
INSTALL STEAM HOSE
8

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.
Note: The humidifier uses cold water to temper drain water to less than 140°F. However, if a drain cycle is initiated when the canister is in full
boil, the temperature of the drain water could spike for a few seconds up to 170°F.
AUTOMATIC DIGITAL CONTROL AND CONTROL WIRING
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 (steam dispersion tube if it is in the return.) Follow instructions provided with the control. Connect “H” terminals on
ADHC to “HUMIDISTAT” terminals on humidifier circuit board.
If the application requires a wall-mounted humidistat in the conditioned space, use Manual Humidistat Part #4655 or Digital Manual Humidistat
Part #65. In order to allow the humidifier to turn on the HVAC system blower when humidity is required with either of these humidistats, use
Blower Activation Relay Part #4851.
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 7.
INSTALLATION INSTRUCTIONS (CONTINUED)
24 VAC from HVAC
Equipment “R” & “C”
Communication with
Aprilaire 8570 Thermostat
Outdoor Temperature Sensor
Heat Signal from HVAC Equipment
Fan Signal from Thermostat
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 NC connection when
measured RH is above setpoint RH.
HGfRCAB ODT GWH
FAN PACK HUMIDISTAT
CNO NC
C
NO
NC
FIGURE 7 – Model 800 Accessory Wiring
90-1544
9

ELECTRICAL POWER WIRING & SHUT-OFF SWITCH
All wiring must be installed in accordance with all governing electrical codes and with the wiring diagram provided inside the front panel.
Power wiring must be rated for 105°C (220°F).
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.
Humidifier draws 11.5 amps ±10%. Use 12.7 amps when sizing circuit.
The Model 800 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 attached to L1 tab on the power terminal block to the proper tab on the
transformer terminal block.
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.
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 located on the top of the humidifier.
Connect power and ground wiring as shown in appropriate wiring diagram.
 •240VAC–Figure 8
 •208VAC–Figure 9
 •120VAC–Figure 10
Do not run high voltage power lines over internal circuit boards.
INSTALLATION INSTRUCTIONS (CONTINUED)
10

NOTE: MODEL 800 IS SHIPPED
FROM THE FACTORY WIRED IN
THE 240 VOLT CONFIGURATION.
(PROVIDED)
(NOT PROVIDED)
MAIN POWER SWITCH
J10-1
AUTOMATIC DIGITAL
J1-1
J1-2
ELECTRODE
WATER LEVEL
ELECTRODE
24V AC
COM
ORG
BLU
J5
J2
RED
RED
BLK
BLK
YEL
YEL
BRN
BRN
BLU
WHT
WHT
COM
24V AC
COM
24V AC
COM
24V AC
DRAIN VALVE
FILL VALVE
POWER RELAY COIL
J3
J4
J6-2
J6-1
J8
J7
120/208/240 VAC
SAFETY SWITCH
BLU
+24V DC
+24V DC
J11-2
J11-1
J13-2
J13-1
J12-2
J12-1
STEAM CYLINDER
J3-2
J3-1
J1-2
10
L1 N, L2
TERMINAL
BLOCK
BLK
BLK
42
68
24V AC
YELBLU
CONTROL PCB CURRENT SENSING PCB
J1-1
HUMIDITY CONTROL
HIGH LEVEL PROBE
(OPTIONAL)
FAN PACK
+24V AC
COM
HUMIDISTATFAN
BLK
YEL
YEL
POWER RELAY CONTACTS
PROBE
J4
J2
J10-2
DISPLAY PANEL
RIBBON CABLE
GROUND
TRANSFORMER
75VA
208 240
120
WHT
BLK / WHT
RED ORG
BLK
VIO UNUSED 480V LEAD
JUMPER WIRE
CONTROL CIRCUIT WIRING
HIGH VOLTAGE WIRING
FIELD WIRING
STATIC
DISCHARGE
GROUND
FIGURE 8 – 240 VAC Wiring Diagram
90-1660
INSTALLATION INSTRUCTIONS (CONTINUED)
11

NOTE: MODEL 800 IS SHIPPED FROM
THE FACTORY WIRED FOR 240 VOLTS.
THE BLACK / WHITE WIRE FROM L1
MUST BE MOVED TO THE 208 VOLT
TERMINAL FOR 208 VOLT OPERATION.
(PROVIDED)
(NOT PROVIDED)
MAIN POWER SWITCH
J10-1
AUTOMATIC DIGITAL
J1-1
J1-2
ELECTRODE
WATER LEVEL
ELECTRODE
24V AC
COM
ORG
BLU
J5
J2
RED
RED
BLK
BLK
YEL
YEL
BRN
BRN
BLU
WHT
WHT
COM
24V AC
COM
24V AC
COM
24V AC
DRAIN VALVE
FILL VALVE
POWER RELAY COIL
J3
J4
J6-2
J6-1
J8
J7
120/208/240 VAC
SAFETY SWITCH
BLU
+24V DC
+24V DC
J11-2
J11-1
J13-2
J13-1
J12-2
J12-1
STEAM CYLINDER
J3-2
J3-1
J1-2
10
L1 N, L2
TERMINAL
BLOCK
BLK
BLK
42
68
24V AC
YELBLU
CONTROL PCB CURRENT SENSING PCB
J1-1
HUMIDITY CONTROL
HIGH LEVEL PROBE
(OPTIONAL)
FAN PACK
+24V AC
COM
HUMIDISTATFAN
BLK
YEL
YEL
POWER RELAY CONTACTS
PROBE
J4
J2
J10-2
DISPLAY PANEL
RIBBON CABLE
GROUND
TRANSFORMER
75VA
208 240
120
WHT
BLK / WHT
RED ORG
BLK
VIO UNUSED 480V LEAD
JUMPER WIRE
CONTROL CIRCUIT WIRING
HIGH VOLTAGE WIRING
FIELD WIRING
STATIC
DISCHARGE
GROUND
FIGURE 9 – 208 VAC Wiring Diagram
90-1659
INSTALLATION INSTRUCTIONS (CONTINUED)
12

NOTE: MODEL 800 IS SHIPPED FROM
THE FACTORY WIRED FOR 240 VOLTS.
THE BLACK / WHITE WIRE FROM L1
MUST BE MOVED TO THE 120 VOLT
TERMINAL FOR 120 VOLT OPERATION.
(PROVIDED)
(NOT PROVIDED)
MAIN POWER SWITCH
J10-1
AUTOMATIC DIGITAL
J1-1
J1-2
ELECTRODE
WATER LEVEL
ELECTRODE
24V AC
COM
ORG
BLU
J5
J2
RED
RED
BLK
BLK
YEL
YEL
BRN
BRN
BLU
WHT
WHT
COM
24V AC
COM
24V AC
COM
24V AC
DRAIN VALVE
FILL VALVE
POWER RELAY COIL
J3
J4
J6-2
J6-1
J8
J7
120/208/240 VAC
SAFETY SWITCH
BLU
+24V DC
+24V DC
J11-2
J11-1
J13-2
J13-1
J12-2
J12-1
STEAM CYLINDER
J3-2
J3-1
J1-2
10
L1 N, L2
TERMINAL
BLOCK
BLK
BLK
42
68
24V AC
YELBLU
CONTROL PCB CURRENT SENSING PCB
J1-1
HUMIDITY CONTROL
HIGH LEVEL PROBE
(OPTIONAL)
FAN PACK
+24V AC
COM
HUMIDISTATFAN
BLK
YEL
YEL
POWER RELAY CONTACTS
PROBE
J4
J2
J10-2
DISPLAY PANEL
RIBBON CABLE
GROUND
TRANSFORMER
75VA
208 240
120
WHT
BLK / WHT
RED ORG
BLK
VIO UNUSED 480V LEAD
JUMPER WIRE
CONTROL CIRCUIT WIRING
HIGH VOLTAGE WIRING
FIELD WIRING
STATIC
DISCHARGE
GROUND
FIGURE 10 – 120 VAC Wiring Diagram
90-1658
INSTALLATION INSTRUCTIONS (CONTINUED)
13

When the Automatic Digital Humidifier Control (ADHC) detects RH below the set point, and provided the humidifier is turned on and the HVAC
system blower is operating, the internal controller in the humidifier energizes the electrodes and measures the current flowing through the water
between them. The controller adjusts water level in the canister via a fill valve and a drain valve to maintain current at a nominal 11.5 amps. The
operating water level in the canister depends on the mineral content of the water which determines conductivity.
The ADHC has the ability to turn on the HVAC system blower if the homeowner or installer chooses to utilize that feature. See ADHC installation
manual.
SEQUENCE OF OPERATION
START-UP PROCEDURE
1. Once the supply water, drain, steam hose, electrical power and control wiring connections are complete, make sure canister is fully seated
into drain valve and three wire connectors on top of canister are secure. (High water probe wire and two interchangeable electrode wires.)
2. Attach side panel and front door.
3. Open saddle valve allowing water to flow to humidifier. Check for leaks.
4. Turn Automatic Digital Control knob to OFF.
5. Close main power switch energizing humidifier.
6. Press On/Off button on humidifier. The On/Off light will illuminate green.
7. Make sure the HVAC blower is operating and adjust the ADHC dial up to initiate a call for humidity.
Note: The ADHC can be placed into TEST mode to force a call for humidity but this only lasts for one minute.
The Steam light will illuminate green indicating a call for humidity and the Fill light will illuminate green indicating the fill valve is open
allowing the canister to fill. You should also hear the water flowing. If water flows down drain while humidifier is filling, check for kinks in
hoses and make sure O-ring is properly seated in groove in drain valve.
8. Once the Fill light turns off, to verify that the humidifier will drain properly, press the On/Off button to turn humidifier off. You may hear the
fill valve open allowing cold water to flow into the canister to cool the water in the canister. The Drain light will flash green for 15 seconds
then turn green for four minutes while the canister drains. Once the Drain light turns off, the drain cycle is complete.
9. Set ADHC to proper level.
10.Press On/Off button to turn humidifier on.
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When the humidifier is powered and turned on, the “On/Off” light is illuminated green.
During fill cycles, the “Fill” light illuminates green.
When the humidifier is turned on, any time the ADHC sends a call for humidity, the Steam light illuminates green.
Any time the drain valve is activated, the “Drain” light illuminates green.
During initial start up with a new canister, the humidifier may run through a series of fill/drain cycles until the conductivity of the water is in
a range that allows the humidifier to generate steam at the rated capacity. If the conductivity of the water is low, it may take several days for
the humidifier to generate steam at the rated capacity. The rated capacity is achieved when the humidifier is detecting 11.5 amps of current
between the electrodes. If the humidifier has not reached capacity after 168 hours of operation, the Steam light will illuminate yellow on a call
for humidity. The humidifier will continue to operate with a yellow Steam light, and may satisfy the humidity requirements. Once rated capacity
is reached, the Steam light will illuminate green.
The internal controller adjusts water level in the canister to maintain a nominal current of 11.5 amps between the electrodes. As minerals build
up on the electrodes, their effectiveness decreases, so the controller will increase the water level to submerge more of the electrode surface.
When the water has reached the high level probe in the canister and the internal controller no longer detects nominal current, the Service light
will flash red indicating that the canister needs to be replaced.
If the humidifier attempts to drain the canister and cannot, the drain and fill valves will pulse on & off for four seconds to dislodge minerals
which may be blocking the drain valve ports. The Drain and Fill lights will flash on & off when this occurs.
Any time power is disconnected or humidifier is turned off, the internal timer for start-up and drain cycles is reset.
If the humidifier has operated 168 hours without a drain cycle, the drain valve will open and drain the canister. Normal operation will continue.
If the humidifier is operating and a power failure occurs, once power is restored, the “On/Off” light will flash green for one minute, then the
humidifier will turn on.
OPERATING MODES
END OF SEASON/PERIOD OF INACTIVITY SHUT-DOWN
The humidifier does not need to be turned off at the end of the humidification season. If 72 hours elapses without receiving a call for humidity,
the canister will automatically drain. The Drain light will remain lit for 24 hours. This may also occur during periods of inactivity during the
humidification season. The humidifier will resume normal operation when a call for humidity is made.
To turn humidifier off, push ON/OFF button once. Humidifier will enter four-minute drain cycle. Fill valve will open to temper drain water. The
Drain light will flash green for 15 seconds then turn green for four minutes while the canister drains. Once the Drain light turns off, the drain
cycle is complete and the humidifier is off.
SHUT DOWN PROCEDURE
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DISPLAY PANEL
TABLE 4 – Display Panel
Indicator Light Function
Off Humidifier is turned off or power is disconnected.
Solid green Humidifier is turned on.
Flashing Green Humidifier is preparing to turn on. Occurs if power to humidifier was turned off when humidifier
was on. Humidifier turns on after light flashes for one minute.
Off Fill valve not energized.
Solid Green Fill valve is energized, filling or replenishing canister with water. (During drain cycle when fill valve
is open allowing cold water into canister to temper drain water, the fill light does not illuminate.)
Flashing Green Fill and Drain Valves are pulsing to dislodge mineral deposits from drain. Flashes 10 times in 4
seconds. Occurs if high water probe detects water during drain cycle.
Solid Red Humidifier cannot fill canister. Humidifier stops operating. Occurs after fill valve has been energized
for 40 minutes and high water probe does not detect water.
Off Humidifier is not producing steam
Solid Green Humidifier is turned on and receiving a call for humidity from the control.
Solid Yellow Humidifier is producing steam but at less than the rated capacity. Occurs if humidifier has operated
for 168 hours and does not detect nominal 11.5 amps between electrodes.
Off Drain valve not energized.
Solid Green Drain valve is energized, allowing water to drain from canister.
Flashing Green Humidifier is preparing to drain. Flashes for 15 seconds indicating fill valve is open allowing cold
water into canister.
Flashing Red
Canister has reached end of life. Humidifier continues to operate but at reduced capacity. Occurs
after humidifier has operated for 168 hours plus another 24 hours at less than 75% of the maximum
operating current level between electrodes.
Solid Red Humidifier is not operating and requires service.
Green lights indicate normal operation.
Yellow Steam light indicates humidifier is operating at less than rated capacity. Yellow Steam light also indicates humidifier is in Test mode.
Flashing red Service light indicates canister has reached the end of its life and needs to be replaced.
Solid red lights indicate humidifier has shut down and requires service.
Disconnecting power to humidifier resets internal timers.
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MAINTENANCE
Inspect humidifier when servicing.
•Checksystemoperationandinspectallplumbingconnectionsandpipingforsignsofcracksorleaks.
•Inspectdrainlinetomakesureitisnotblockedandhasconstantdownwardslope.Cleanorreplaceifnecessary.
•Inspectsteamhosetomakesureithasnolowspotsandhasconstantupwardslopefromhumidifiertodispersiontubeinduct.Ifdispersion
tube is mounted below humidifier, inspect drip tee and drain.
Replace the canister annually and when prompted by the “Service” light. Use Only Genuine Aprilaire Model 80 Canister.
1. Press On/Off switch to turn humidifier off.
2. Allow humidifier to drain. When the green Drain light stops flashing, disconnect main electrical power to humidifier.
3. Remove front panel.
4. Pull three wires off posts on top of canister. (Two large electrode conductors and one water level probe conductor.)
5. Loosen hose clamp at top of canister.
6. Slide hose off top of canister.
7. Slide canister up and out of drain assembly. Discard canister.
8. Remove O-ring from groove in drain assembly using small screw driver.
9. Inspect drain assembly and remove any debris.
10. Insert new O-ring into groove in drain assembly. (O-ring is provided with Model 80 canister.) Dampen O-ring with water before inserting
canister. Do not use oil, grease, or any lubricant besides water.
11. Make sure strainer is inserted into bottom of new canister.
12. Insert canister into drain assembly. Position canister with label facing outward.
13. Slip steam hose over top of canister and tighten hose clamp.
14. Reattach three wires to posts on top of canister. (Larger electrode conductors are interchangeable.)
15. Replace front panel.
16. Restore electrical power to humidifier.
17. Turn humidifier on and verify green On/Off light is illuminated.
18. See Start-up procedure.
TO REPLACE THE CANISTER
TO SERVICE THE FILL VALVE
If water flow from fill valve is restricted, disconnect inlet fitting and remove in-line strainer from inlet port using small screw. Clean or replace
strainer.
CAUTION
• Allow humidier to drain and disconnect power before servicing.
• Service should be performed by a qualied HVAC technician.
17

CHECKING SYSTEM OPERATION & TROUBLESHOOTING
The following troubleshooting guide is intended to help diagnose and resolve general operational problems with Model 800 Humidifier. If a
problem persists, call Aprilaire Tech Support toll-free at 1-800-334-6011. Please be prepared to describe the exact nature of the problem.
For general operational problems, check to make sure humidifier is installed correctly.
CAUTION
Contact with electrical circuits can cause property damage, personal injury or death. Service and Troubleshooting must be
performed by qualified electrician.
TEST MODE
To check general function of humidifier and components, the following Test Mode procedure can be performed. Humidifier must be powered and
ADHC knob must be turned to OFF position. The humidifier should be plumbed to a water supply and the drain line should be connected. Test
Mode involves repeatedly pressing the On/Off button and listening for audible clicks as the various components are energized and de-energized.
The humidifier will remain in Test Mode for five minutes, then automatically return to the Off state. If the procedure is not completed in five
minutes, restart Test Mode. If the humidifier or components do not respond as indicated, investigate components being tested.
1. Press the On/Off button and hold it for 10 seconds until all display lights turn on. On/Off, Fill, steam and Drain lights will be green. Service
light will be red.
2. Press On/Off button again. All display lights will turn off.
3. Press On/Off button again. Fill light will illuminate red and Steam light will illuminate yellow.
4. Press On/Off button again. Red Fill light will turn off. Steam light will remain yellow.
5. Press On/Off button again. Listen for audible click as Power Relay is energized. If click is not heard, remove brown wires from terminals J7
and J8 and measure voltage across terminals J7 and J8. If 24 VAC is present, replace Power Relay. If 24 VAC is not present, replace control
circuit board.
6. Press On/Off button again. Listen for audible click as power relay is de-energized. If click is not heard, remove brown wires from terminals
J7 and J8 and measure voltage across terminals J7 and J8. If less than 1 VAC is present, replace power relay. If more than 1 VAC is present,
replace control circuit board.
7. Press the On/Off button again. Listen for a click as the fill valve is energized. Water should flow, filling the canister. If the valve does not
energize. measure voltage across the J6 FILL terminals on the control circuit board. If 24 VAC is present, replace fill valve. If 24 VAC is not
present, replace control circuit board.
8. Press On/Off button again. Listen for click as fill valve is de-energized. Water should stop flowing. If valve remains energized, check for
voltage across “J6 FILL” terminals on control circuit board. If less than 1 VAC is present, replace fill valve. If more than 1 VAC is present,
replace control circuit board.
9. Press the On/Off button again. Listen for a click as the drain valve is energized. Water should flow down the drain. If the valve does not
energize, remove the drain valve wires from terminals J3 and J4 on the control circuit board and measure voltage across the terminals. If 24
VAC is present, replace drain valve. If 24 VAC is not present, replace control circuit board.
10. Press On/Off button again. Listen for click as drain valve is de-energized. Water should stop flowing down the drain. If valve remains
energized, remove the drain valve wires from terminals J3 and J4 on the control circuit board and measure voltage across the terminals. If
less than 1 VAC is present, replace drain valve. If more than 1 VAC is present, replace control circuit board.
11. Press the On/Off button again. Listen for a faint click as the FAN PACK terminals on the control circuit board are energized. If the terminals
do not energize, (24 VAC measured across terminals) replace the control circuit board.
12. Press On/Off button again. Listen for click as FAN PACK terminals are de-energized. If the terminals fail to energize (more than 1 VAC
measured across terminals) replace control circuit board.
Exit Test Mode by disconnecting power to humidifier or allowing five minutes to elapse.
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TABLE 5 – Troubleshooting Guide
Problem Possible Cause Action
General operating
problems. Humidifier
will not turn on or
turn off.
Field-wired terminal
connections. Check L1, N/L2 and Ground connections.
Check HUMIDISTAT and FAN PACK Terminal connections.
HUMIDISTAT terminals must be connected to an on/off device. Control circuit board will be damaged
if If 24 volts are connected to HUMIDISTAT terminals.
Check wiring connections and settings on Accessory items such as high limit switch and airflow
proving switch.
Internal connections. Check electrode and high water probe connections on the top of the canister.
Make sure blue/white wire jumpers (2) connecting Control PCB and Current Sensing PCB are secure
and properly oriented. See Wiring diagram Figure 8, 9or 10.
Make sure ribbon cable from membrane switch is securely plugged into control circuit board.
Check that terminals from internal components are securely attached to proper tabs on circuit boards.
Make sure one of the electrode wires extends through toroid ring on current sensing circuit board.
Make sure Black/white wire from L1 is attached to terminal that matches input voltage.
No power to humidifier. Check main power supply and switch.
Check for proper voltage across L1 and N/L2 terminals.
Humidifier not turned on. Make sure front cover is attached to engage safety interlock switch. Press On/Off button.
No power to 24 volt control
circuit. Make sure ribbon cable from membrane switch is securely plugged into control circuit board.
Check reset switch on transformer.
With humidifier energized, check for 24± 6 volts AC across J2 & J5 terminals. If okay, check for 5
Volts DC across +5V and GND test points on control circuit board. If okay, replace membrane switch.
If not, replace control circuit board.
If 5 volts DC are not present between +5V and GND test points, remove blue/white wire jumpers and
check DC voltage across +5V and GRD points. If 5 Volts DC are present, replace current sensing circuit
board. If 5 volts DC are not present, replace control circuit board.
Steam Light does not
turn on. Call for humidity not being received. Check ADHC wiring and setting. (Do not leave ADHC in TEST mode.)
Check wiring and settings of high RH limit switch and airflow proving switch.
Water is leaking from
humidifier. Loose plumbing connections. Check water supply connection at fill valve inlet. Tighten as needed.
Check internal hose clamp connections. Reposition clamps and tighten as needed.
Check steam hose connection on top of canister. Tighten clamp as needed.
Hoses are blocked. Check internal hoses and eliminate kinks or blockage.
Drain hose is blocked. Make sure drain hose has constant downward slope and is not blocked.
Water constantly runs
down drain. Malfunctioning drain valve. Check valve function using Test Mode.
Debris in drain valve
preventing it from closing. Remove canister and clean debris from drain valve.
O-ring in drain valve is not
properly seated in groove. Remove canister and reposition O-ring.
Water is flowing from fill
cup overflow port. Check internal hoses and eliminate kinks or blockage.
Disassemble brass fitting in feed line between inlet valve and fill cup. Make sure small rubber flow
orifice is in place in brass fitting.
High static pressure in duct
is causing back pressure in
canister.
Make sure dispersion tube is not discharging into duct with greater than 2.0 in.wg static pressure.
CHECKING SYSTEM OPERATION & TROUBLESHOOTING (CONTINUED)
19

TABLE 5 – Troubleshooting Guide (continued)
Problem Possible Cause Action
Humidifier is filling and
draining at the same time. Internal wiring connections. Make sure blue/white wire jumpers (2) connecting Control PCB and Current Sensing PCB are secure and properly oriented. See Wiring diagram Figure 8, 9or 10.
Water is flowing down drain
while humidifier is making
steam (Steam light illuminated
green or yellow).
O-ring is not properly inserted. Remove canister and make sure O-ring is seated in groove in drain valve.
Humidifier makes gurgling
sound. Excess condensation in steam hose. Make sure steam hose has constant downward slope to humidifier or to tees and traps in low spots of hose.
If hard pipe is used for dispersion system, make sure it is insulated.
Fill valve makes banging
sound. Water hammer from line pressure. Make sure water supply line does not contact ductwork.
Install shock arrestor.
Install section of 1/4" braided fill line. Conform to local codes.
If water supply pressure is greater that 120 psi, install pressure reducer.
Humidifier will not fill. Saddle valve not open. Open saddle valve.
Malfunctioning fill valve. Check valve function using Test Mode.
Hoses are blocked. Check internal hoses and eliminate kinks or blockage.
Humidifier fills constantly. Internal wiring connections. Make sure blue/white wire jumpers (2) connecting Control PCB and Current Sensing
PCB are secure and properly oriented. See Wiring diagram Figure 8, 9or 10.
Humidifier will not drain. Debris in drain valve blocking outlet port. Remove canister and clean debris from drain valve.
Malfunctioning drain valve. Check valve function using Test Mode.
Water in duct from dispersion
tube. Dispersion tube installed incorrectly. Install dispersion tube with tublets facing straight up.
Impurities in steam hose or pipe causing
foaming. Rinse canister and hose in clean water.
Service light flashing red
before end of humidification
season.
Canister full of mineral deposits. Remove canister and rinse with clean water.
Plumb humidifier to filtered water.
Plumb humidifier to softened water.
Humidifier runs in short cycles (does not
reach capacity). Use blower activation feature on ADHC or run constant HVAC fan.
Yellow steam light. Humidifier operating below rated
capacity. (Normal operation for systems
plumbed to low conductivity water and
systems that operate for short cycles.)
Plumb humidifier to softened water.
Use blower activation feature on ADHC or run constant HVAC fan.
Operate humidifier on 240 volts.
To determine operating current, attach clamp-on ammeter to one of the
electrode wires on top of canister.
A small amount of salt (1/10 tsp or one fast-food salt packet) can be added to
fill cup to introduce conductive minerals to canister. Do not over-salt. System
will drain and refill with clean water, further prolonging start.
Humidifier is not satisfying
demand. Control setting is too low. Adjust control to higher setting.
Control mounted in wrong location. See Installation Instructions with control for correct mounting location.
Short run times. Use blower activation feature on ADHC or run constant HVAC fan.
Humidifier capacity limited by input
power (120V). Operate humidifier on 240 volts.
Excess humidity. Control setting is too high. Adjust control to lower setting.
Control mounted in wrong location. See Installation Instructions with control for correct mounting location.
CHECKING SYSTEM OPERATION & TROUBLESHOOTING (CONTINUED)
20