Autoflo 250, Sc-15 Owner's Manual

FOR USE WITH GAS, OIL, and HYDRONIC FORCED AIR FURNACES

Installation Instructions

Owner’s Manual

MODEL SC-15 & MODEL 250

FLOW-THRU HUMIDIFERS

SEQUENCE OF OPERATION

The AUTOFLO Model’s SC-15 & 250 use the evapo
rative principal to add moisture to the warm air heat
ing system. Upon a demand for humidity from the
humidity control, the water solenoid valve opens and
water flows in at the top of the media pad and is
evaporated, as warm air passes through the media
pad. When the moisture laden air re-enters the duct
it is mixed with dry air already flowing through the
duct. This moisture laden air gradually increases the
relative humidity level in the home.

RECOMMENDED LOCATION

TEMPERATURE AND SAFETY REQUIREMENTS

Refer to the rating plate on the furnace for minimum
clearances to combustible construction. All parts
and connections of an AUTOFLO humidifier must
be installed outside of the minimum clearance
requirements for rear, top, sides, and flue of furnace.
Do not install where humidifier or water connections
may be exposed to freezing temperatures or outside
weather. Attic installations are NOT recommended.
If you have central air conditioning, carefully plan
the location of the plenum opening to prevent
damage to the cooling coil or other components
inside the duct.

STEP BY STEP INSTALLATION

-

-

CAUTION: Installation should be performed by
qualified personnel only. Use eye protection and
gloves when drilling and handling sheet metal. All
work must be performed to local & national codes
and ordinances. Use multi-conductor 18 awg solid
copper wire. Provide over-current protection as
required. DO NOT omit the drain or overflow tubing.

DRILL MOUNTING HOLES AND CUT OPENING

MODEL SC-15

Turn off power to the furnace before installing the
humidifier. Test fit the SC-15 housing on the side of
the warm air plenum. Before proceeding, verify that
adequate clearances are available for servicing the
media pad. There must also be adequate room (5
1/2 inches) inside the plenum for the louver. If
necessary, relocate the unit. Use a plumb line or a
level to make sure the housing is level. With a
permanent marker outline the inside edge of the
housing. Also mark the twelve holes to be drilled.
Center punch and drill all twelve holes as indicated
by the marks. Drill or punch a starter hole and then
use tin snips to cut out the rectangular shaped open
ing. The opening should be 1/8 inch larger on all
four sides than what was marked.

-

HUMIDIFIER MOUTING LOCATION

The AUTOFLO model SC-15, is to be mounted on
the supply duct of the furnace only. Model 250 can
be mounted on the supply or the return duct of the
furnace.

HUMIDISTAT MOUNTING LOCATION

The humidistat can be mounted on the cold air return
duct to sense the cool dry air returning to the
furnace. It can also be mounted on an interior wall
near the furnace thermostat as well. The electrical
connections and basic wiring are the same for duct
mounted or wall mounted humidistats.

TB 218 Part#090375A0218 Rev. B 12122006SC15250

®

281 Keyes Ave. Hampshire, IL 60140 • 847-683-7990 • Fax [phone] • www.bestairpro.com

Copyright 2007 © , All Rights Reserved

MOUNTING HUMIDIFIER

Hold the housing next to to duct and start four #8 x
3/4 inch long sheet metal screws through the holes
in the bottom edge of the humidifier. With these four
screws started the unit should remain in place while
starting the other eight screws. With all twelve of
the screws started they can now be tightened. With
the housing mounted the louver can be installed.
This should be done by rotating the louver to the
proper position depending on the direction of air
flow. The air flow should enter into the curved
multi-louvers and exit out of the large opening.

®

1

SC-15

Horizontal flow

Blower
Motor

Place
Baffle
Here

BY PASS

SC-15 mounts

e supply

to th
duct only.

Up Flow

Side Cutaway View
Model SC-15 mounted
on the supply plenum
of an Upflow Furnace

SC -15

DRILL MOUNTING HOLES AND CUT
OPENING MODEL 250

Supply
Duct

250

R etur n D uc t

Up Flow

Horizontal flow

250

250

Supply Duct

Down Flow

Return
Duct

Mount the model 250 using all the same precau­tions as in mounting the SC-15. Use the mounting
template to locate the humidifier on the duct work.
Tape down the template for the humidifier and for
the by pass duct adaptor. Drill and cut all holes that
go with each template. Mount the adaptor and the
baffle with the (6) 3/8” screws from the kit. Mount
the humidifier by first putting in the bottom of the
humidifier housing to catch the lip on the back of the
housing. Then use the (10) 1/2” screws that come
in the kit to mount the housing to the duct. Install
the field supplied bypass duct and end cap. First
route the bypass duct from the duct adaptor to one
side of the humidifier housing. Drill 2 holes through
the bypass duct and the duct adaptor. Install (2)
3/8” screws from the kit on each end of the humidi

­fier housing. There are pre-punched holes. Use
them to line up and mount the bypass duct and end
cap with (2) 1/2” screws from the kit. Open the
Bypass Baffle during the winter and close it during
the summer.

Mounting the
Model 250

Model 250
Bypass baffle
and duct adaptor.

®

281 Keyes Ave. Hampshire, IL 60140 • 847-683-7990 • Fax [phone] • www.bestairpro.com

Copyright 2007 © , All Rights Reserved

®

2

MODEL SC-15

PARTS LIST

Unpack the Autoflo model SC-15 humidifer and familiarize yourself with the following parts:

1. Model SC-15 Humidifier

2. Small parts bag containing:
a. Two #8 x 3/4” sheet metal screws
b. Twelve #8 x 3/8” sheet metal screws

3. Saddle tapping valve kit

4. 24 volt humidistat

5. 24 volt transformer

6. 1/2” drain hose

7. 1/4” plastic tubing

8. Evaporative media pad

9. Owner’s manual

ADDITIONAL RECOMMENDED PARTS

1. Relay, with 120 volt current sensing coil for furnaces
with multi-speed blower motors.

2. 4x4 wire box to mount transformer and enclose line
voltage connections.

3. #18awg thermostat wire to make up any and all
24 volt connections

4. 1/2” drain hose clamp.

®

281 Keyes Ave. Hampshire, IL 60140 • 847-683-7990 • Fax [phone] • www.bestairpro.com

Copyright 2007 © , All Rights Reserved

®

3