Aprilaire 500M Installation Instructions

The current Model 500 is identical to the previous Model 500A (except the 500A came with a 2nd spare water panel).
READ COMPLETE SAFETY INSTRUCTIONS AND INSTALLATION TEMPLATE BEFORE STARTING
This product must be installed by a qualified heating and air conditioning contractor. Failure to do so could result in serious injury from electrical shock.
WARNING
ELECTRICAL SHOCK HAZARD.
1.
Disconnect electrical power to the
furnace before starting installation.
Failure to do so could result in
serious injury from electrical shock.
SHARP EDGES HAZARD.
2. Sharp
edges may cause serious injury from
cuts. Use care when making plenum
openings and handling ductwork.
RISK OF SCALDING.
3. Water
temperature over 125°F can cause
severe burns and scald instantly.
Shut off the hot water supply before
disconnecting or tapping into any
hot water supply line.
(SEE STEP 7 ON BACK AND "HUMIDIFIER CONTROL SAFETY AND INSTALLATION INSTRUCTIONS" FOR DETAILED WIRING INSTRUCTIONS)
Model 500M
MANUAL CONTROL
IMPORTANT
USE 120 VAC POWER SOURCE OTHER THAN FURNACE MOTOR
CIRCUIT. HOWEVER, THE TRANSFORMER CAN BE POWERED
OFF THE HOT 120 VAC LINE BEFORE IT ENTERS THE FURNACE.
• DO NOT WIRE TRANSFORMER INTO FURNACE BLOWER CIRCUIT.
24 VAC FURNACE
ACCESSORY TERMINALS
OR TRANSFORMER
(10VA MINIMUM)
WATER SUPPLY
COMMON
HI
LO
FURNACE
BLOWER MOTOR
MODEL 50
CURRENT
SENSING RELAY
(IF REQUIRED)
IMPORTANT
WHEN MODEL 50 CURRENT SENSING RELAY IS USED:
• WIRE MODEL 50 CURRENT SENSING RELAY INTO
24 VAC HUMIDIFIER CONTROL CIRCUIT ONLY!
DO NOT INSTALL IN TRANSFORMER PRIMARY CIRCUIT.
90-1207
RESEARCH PRODUCTS CORPORATION • P.O. BOX 1467 • MADISON, WI 53701-1467 • CALL 800/334-6011 • FAX 608/257-4357
ATTENTION INSTALLER:
This product must be installed in compliance with all local, state and federal codes.
SMALL BYPASS HUMIDIFIER MODEL 500M AND 500A
For Aprilaire Humidifier Parts Drawing 2007, click here.
RISK OF PROPERTY AND EQUIPMENT DAMAGE.
1. Do not install humidifier where freezing temperatures
could occur. The water line could freeze and crack
causing water damage to the home.
2. Do not install humidifier or bypass connection on the
furnace jacket.
3. Do not install humidifier or bypass connection on a
plenum face where the blanked off ends of the cooling
coil will restrict air movement through the humidifier.
4. Do not set humidity level above recommended or to
recommended level if condensation exists on inside
windows of any unheated space, as condensation
damage may result. Excess humidity can cause
moisture accumulation which can allow the possibility
for mold growth in the home.
RECOMMENDED WIRING DIAGRAMS
Model 500A
AUTOMATIC DIGITAL
HUMIDIFIER CONTROL
SHUT-OFF
(SADDLE VALVE)
CONTINUOUSLY POWERED
24 VAC TRANSFORMER
PROVIDED WITH HUMIDIFIER
IMPORTANT
DO NOT WIRE TRANSFORMER
INTO FURNACE BLOWER CIRCUIT.
YELLOW 24V
SOLENOID
VALVE WIRES
NORTH, EAST
OR WEST SIDE
OF HOME
OUTDOOR
TEMPERATURE
SENSOR OR
MANUAL MODE
CONNECT DRAIN LINE HERE
RESISTOR
ABOVE EXPECTED
SNOW LINE
CAUTION
5. Do not connect Model 500M or 500A
transformer to blower motor wiring.
Premature component failure may result.
6. When installing Humidifier Control on downflow
furnace, ensure blower continues to run after a
heat call is satisfied to eliminate high temperatures
from damaging the Humidifier Control.
7. Do not install humidifier where water pressure
exceeds 125 psi, since damage to the humidifier
may result. Follow codes in effect concerning
pressure reduction.
8. Do not install humidifier on systems with
greater than 0.4 in. wg pressure differential
between supply and return plenums.
R C A B ODT W/G Cf H
WATER SUPPLY
CONSULT FURNACE MANUFACTURER FOR VOLTAGE AND
OPERATION PARAMETERS OF ACCESSORY TERMINALS.
24 VAC FURNACE
TERMINALS MAY BE LABELED: "HUM", "ACC" OR "EAC"
ACCESSORY TERMINAL
NOTE: IF 120V, INSTALL 24V TRANSFORMER.
COMMON
24V ACTIVATED WITH HEAT CALL.
NOTE: SEE CONTROL INSTRUCTIONS FOR OTHER
WIRING OPTIONS.

SPECIFICATIONS

HUMIDIFIER DIMENSIONS
Width
(including solenoid valve):
Height
(including drain spud):
Depth
BYPASS DUCT OPENING
6" diameter
PLENUM OPENING
9 1 ⁄ "W x 9
2
WATER FEED RATE
3 gph
ELECTRICAL DATA
24 VAC-60 Hz, 0.5 AMP
INSTALLATION OPTIONS
The Model 500M and 500A Aprilaire can be
installed on either the supply or return
plenum of a forced air handling system and
is easily reversible for installation with
right hand or left hand bypass duct
connections. The humidifier dimensions
and serviceability must be considered
when selecting the best location for the
humidifier. Here are 2 examples of many
types of installations.
Upflow
SHUT-OFF
(SADDLE VALVE)
RETURN
YELLOW 24V
SOLENOID
VALVE WIRES
Horizontal
RETURN
CONNECT DRAIN LINE HERE
NOTE
When installing Aprilaire humidifier
on a heat pump system, use hot
water. The heated water supplements
90-1204
the reduced supply air temperature
as added heat for evaporation.
15 ⁄ Ó
5
8
13"
10 1 ⁄ "
:
4
1 ⁄ "H
2
SUPPLY
SUPPLY
90-1079