Skuttle 55 Operating instructions

OWNER’S MANUAL
AND INSTALLATION
INSTRUCTIONS
for Models 55 and 86 Under Duct
Whole-House Humidiers
Includes Safety, Installation,
Operating and Maintenance
Instructions plus Warranty
CAUTION: Read these instructions thoroughly
before beginning installation or maintenance
SAVE THIS MANUAL
FOR FUTURE REFERENCE
Model No.
Serial No.
Installation Date

Table of Contents
Thank You!................................................................................................ 1
Warranty Validation Notice ....................................................................... 1
Skuttle Limited One-Year Product Warranty............................................. 2
How Your Humidier Works...................................................................... 3
Safety Precautions ................................................................................... 4
How Your Skuttle Under Duct Humidier Must Be Installed ..................... 5
How to Operate Your Humidier............................................................. 16
How to Maintain Your Humidier ............................................................ 17
Trouble Shooting Guides........................................................................ 22
FAQs about IAQ ..................................................................................... 24
Skuttle Automatic Flushing Timer ........................................................... 25
Skuttle Model 216 Make-Up Air Control ................................................. 26
Skuttle High-Efciency Air Cleaners ....................................................... 27
The Skuttle “Happy House”—Your Assurance of Enhanced IAQ ........... 28
Contact Information ..................................................................Back Cover
CAUTION: To protect your investment, please read
the Limited One-Year Product Warranty on page 2.

Page 1
Thank you for purchasing a Skuttle Under Duct Humidier. We appreci-
ate your business and are pleased to add your name to our list of valued
customers. We sincerely hope you are satised with our product and its
performance.
Skuttle is the oldest manufacturer of residential humidiers, having been in
business since 1917. In addition to humidiers, we manufacture air lters,
make-up air controls and other IAQ accessories.
As always, quality, performance and customer satisfaction are our highest
priorities. The following information will aid you with the periodic mainte-
nance necessary to keep your humidier operating at peak efciency.
When you need parts or service, rst try calling the heating and air
conditioning dealer who installed your humidier. This information may
be located on the back of this booklet, or the dealer may have placed
a reference label on your heating system. (Parts lists can be found on
pages 18, 19, 20 and 21.)
If you cannot locate your original installer, check the Yellow Pages or
the Internet (e.g., switchboard.com) under “Heating & Air Conditioning
Contractors.”
If these attempts at nding parts or service fail, call us toll-free at (800)
848-9786. We’ll be glad to assist you.
For further instructions regarding the benets, operation and maintenance
of your new Skuttle humidier, please read the applicable sections of this
manual.
•
•
•
IMPORTANT:
Warranty Validation
The completion and return of the Warranty Registration Card—
enclosed separately in your Skuttle humidier carton—is a
condition required for warranty coverage and performance. The
warranty described herein is not valid unless the Warranty Card is
completed and mailed to Skuttle Mfg. Co. within fteen (15) days of
equipment installation.

Page 2
Skuttle Limited One-Year Product Warranty
This limited one-year warranty covers the Skuttle product as designated on the return portion of
the warranty registration card, excluding wiring, plumbing and installation.
Skuttle Manufacturing Company warrants that this product is free from defects in material and
workmanship under normal, non-commercial use and service. Skuttle will remedy any such
defects if they appear within 12 months from the date of the original installation as evidenced
by receipt of the warranty registration card, subject to the terms and conditions of this limited
one-year warranty stated below:
THIS LIMITED ONE-YEAR WARRANTY IS GUARANTEED BY SKUTTLE MANUFAC-
TURING COMPANY, 101 MARGARET STREET, MARIETTA, OH 45750, 740-373-9169.
This warranty shall extend only to any non-commercial owner who has purchased this
residential product other than for purposes of resale.
The completion and return of the warranty registration card is a condition precedent to
warranty coverage and performance. Warranty is not valid unless this card is completed
and mailed to the factory within fteen (15) days of equipment installation.
All components are covered by this limited warranty except expendable items.
If within the warranty period this product or any component requires service, it must be
performed by a competent heating and/or plumbing contractor (preferably the installing
contractor). Skuttle will not pay shipping charges or labor charges to remove or replace
such defective parts or components. If the part of component is found by inspection to
contain such defective material and/or workmanship, it will be either repaired or exchanged,
free of charge, at Skuttle’s option, and returned freight collect.
In order to obtain the benets of this limited one-year warranty, the owner must notify the
dealer or distributor in writing of any defects within thirty (30) days of the discovery. If after
reasonable time you have not received an adequate response from the dealer or distributor,
notify in writing, Skuttle Mfg. Co., 101 Margaret St., Marietta, OH 45750. SKUTTLE WILL
RECEIVE, FREIGHT PREPAID, ONLY REMOVABLE PARTS OR COMPONENTS OF
SUCH DEFECTIVE PRODUCTS.
This limited warranty does not apply to any part or component that is: damaged in transit or
handling; has been subject to abuse, neglect or accident; has not been installed, operated
and serviced according to Skuttle’s instructions; has been operated beyond the factory
rated capacity; or altered in any such way that its performance is affected. There is no
warranty due to neglect, alteration or ordinary wear and tear. Skuttle’s liability is limited to
replacement of defective parts or components and does not include the payment of the
cost of labor charges to remove or replace such defective components or parts.
Skuttle will not be responsible for loss of use of any product; loss of time, inconvenience, or
any other indirect, incidental or consequential damages with respect to person or property,
whether as a result of breach of contract, neglect or otherwise. SOME STATES DO NOT
ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL
DAMAGES, SO THE LIMITATION OF EXCLUSION IN THE PRECEDING SENTENCE
MAY NOT APPLY TO YOU.
THIS WARRANTY GIVES YOU SPECIFIC RIGHTS, AND YOU MAY ALSO HAVE OTHER
RIGHTS WHICH VARY FROM STATE TO STATE.
Any warranty work will be performed within a reasonable time, usually within one-hundred-
twenty (120) days after notice of defect and delivery to the Skuttle factory, subject to delays
beyond the manufacturer’s control.
Any warranty by Skuttle of merchantability, tness or use or any other warranty (express,
implied or statutory), representation or guarantee other than what was set forth herein,
shall expire at the expiration date of this limited warranty. SOME STATES DO NOT ALLOW
LIMITATION ON HOW LONG AN IMPLIED WARRANTY LASTS, SO THE LIMITATION
IN THE PRECEDING SENTENCE MAY NOT APPLY TO YOU.
Skuttle reserves the right to make changes in design and material to its products without
incurring any obligation to incorporate such changes in the units completed on or prior to
the effective date of such change.
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Page 3
How Your Humidier Works
Your Skuttle Under Duct Humidier uses the same principle of evaporation
that you see in nature: a warm breeze passing over an expanse of water
will evaporate the water and raise the relative humidity, just as it does after
a summer shower.
Model 55
When you home is drier than your selected humidity setting, the
humidistat (your humidier’s sensor and control device) turns on
the unit’s internal low-voltage solenoid, allowing water to ow
across the evaporator pad. As the furnace blower forces warm,
dry air across the humidier’s water-soaked pad, some of the
water is evaporated. The newly-moistened air is then circulated
throughout your home by the heating system.
Model 86
When your home is drier than your selected humidity setting, the
humidistat (your humidier’s sensor and control device) turns on
the unit’s low-voltage drum motor. The motor rotates a polyurethane
foam evaporator pad which lifts water out of the water pan and
into the dry air stream. The newly-moistened air is then circulated
throughout your home by the heating system.
It’s important to note that water evaporated from the humidier leaves
behind all the impurities (calcium, iron, lime, bacteria, etc.) that were
originally contained in the water. As a result, these impurities are not
dispersed throughout your home, which keeps your living environment
cleaner and your family safer from harmful contaminants.

Page 4
Safety Precautions
IMPORTANT: Please read these precautions before
installing the Skuttle Under Duct Humidier. Skuttle Mfg.
Co. assumes no responsibility under warranty if the user
and/or installer do not follow directions found in this
manual.
Do not install a humidier where the heating temperatures will exceed
180°F (82°C). Excessively high temperatures will damage your
humidier, possibly resulting in humidier overow and water damage
to the home.
Do not install a humidier where the surrounding temperature may be
32°F (0°C) or colder. Freezing water will damage the humidier and
burst the supply pipe, resulting in damage to the home.
Do not cut or drill into any air conditioning or electrical accessories
during installation of the humidier.
DANGER: Blindness can occur if refrigerant comes in
contact with your eyes; electrocution is possible if you
touch a live electrical wire.
When the humidier is in a nished basement or any area where water
damage could occur, be sure to connect the overow assembly to an
adequately sized drain.
For above-ceiling installation, always install a drain pan plumbed to a
suitable drain.
Although you may prefer a humidity level which is in the “high” range
—particularly when colder outdoor temperatures create drier indoor
conditions—it’s possible that you cannot maintain this setting in your
home. For example, upper levels of humidity cannot be maintained in
homes which do not have reasonably well insulated walls, windows
and doors. In a poorly insulated home, these areas may accumulate
condensation, eventually resulting in damage to the home.
See “How to Operate Your Humidier” (page 16) and “FAQs about
IAQ” (page 24).
The installation, wiring and plumbing of your humidier must comply
with local codes, ordinances and regulations.
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Page 5
How Your Skuttle Under Duct Humidier
Must Be Installed
WARNING: For warranty validation, this humidier
must be installed by a licensed HVAC contractor.
Tools and Materials Needed
The following tools and materials are necessary for proper installation of
your humidier:
Safety goggles
Tin snips or aviation snips
Electric drill or hand drill
3/8" (0.95 cm) and 7/64" (0.28 cm) drill bits
Pliers
Screwdriver (medium-sized flat point)
Pencil or grease pencil
Level
Hammer
Small adjustable wrench
Center punch
Knife
Straight edge yardstick
1/4" (0.64 cm) copper water line
Some installations will require the following, additional materials:
Two conductor, low-voltage wire
1/2" (1.27 cm) I.D. vinyl tubing for Model 55 drain
1/2" (1.27 cm) I.D. vinyl tubing for Model 86 overflow
Selecting an Appropriate Location
Before installing the humidifier, familiarize yourself with the heating system.
Review the typical installations shown in Figures 1-4 for Model 55 (pages
6 & 7), and in Figures 5-8 for Model 86 (pages 7 & 8).
CAUTION: When installing the humidifier, always make
sure the air will be flowing across the unit’s mounting
hinges before it enters the evaporative media.
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Page 6
Typical Installations for Model 55
FIGURE 1: Highboy Furnace 
FIGURE 2: Horizontal Furnace 
FIGURE 3: Lowboy Furnace 

Page 7
FIGURE 4: Counter-Flow Furnace 
Typical Installations for Model 86
FIGURE 5: Highboy Furnace 

Page 8
FIGURE 6: Horizontal Furnace 
FIGURE 7: Lowboy Furnace 
FIGURE 8:
Counter-Flow Furnace

Page 9
Referring to the appropriate Figure, choose a location on the horizontal part
of the duct that is at least 12 inches wide and, if possible, 2 or more feet from
the furnace. This distance allows air turbulence to subside slightly before
entering the humidier. When such distance is not obtainable, additional
ductwork bafing may be needed to permit adequate humidication.
In the same vicinity, you will also need to locate a cold water pipe and a
120-volt power source for the humidier transformer that is within 5 feet of
the humidier. (If the distance is greater, you will need additional wire.)
It is acceptable to wire into the blower circuit, providing the blower is not
multi-speed (see CAUTION, below). The Model 55 ow-thru humidier
must be electrically wired to operate only during blower motor operation in
order to eliminate wasting water while the heater is not running. However,
we suggest that you wire the Model 86 drum-type humidier to operate
independently from the furnace’s blower. This allows the unit to operate
throughout the full blower cycle, thereby eliminating the lag time involved
in starting the humidier.
CAUTION: If the heating system contains a multi-speed
blower motor, it is necessary to isolate the humidier
transformer. This will prevent premature burnout of the
transformer, caused by the inductive current produced
by the motor during high-speed operation. This can be
accomplished in various ways, such as using a pressure
sensor or fan sail switch to detect blower operation,
and using an independent electrical circuit to power the
humidier transformer.
CAUTION: You must comply with all local codes, ordi-
nances and regulations pertaining to plumbing and elec-
trical wiring.
Installing the Mounting Frame
At the selected location, hold the humidier mounting frame (see
Figure 9 on page 10) on the bottom side of the duct so that the long
sides of the frame are parallel to the length of the duct, and the frame’s
hinged end is toward the heating unit, so that the air ow is in the
direction indicated.
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Page 10
FIGURE 9: Humidier Frame
Mark and drill two or three of the mounting holes 7/64" (0.28 cm) in
diameter, and temporarily attach the mounting frame with #8 sheet
metal screws. Mark the remaining holes and center the opening, as
shown in Figures 10 (Model 55) and 11 (Model 86), below.
DANGER: Do not cut or drill into air conditioning or elec-
trical accessories during installation. Blindness can occur
if refrigerant comes in contact with your eyes; electrocu-
tion is possible if you touch a live electrical circuit.
2.
FIGURE 10: Model 55 Opening
FIGURE 11: Model 86 Opening

Page 11
Remove the frame and drill the remaining mounting holes 7/64" (0.28
cm) in diameter. Drill a 3/8" (0.95 cm) diameter hole within the center
section, and cut and remove the rectangular section as previously
marked.
NOTE: When mounting Model 55, an additional notch is
required as shown in Figure 10 (page 10). Measure and
mark as indicated, and cut out this section.
Using #8 sheet metal screws, attach the mounting frame to the duct,
as shown in Figures 9, 10 and 11 (page 10). Make sure the air ows
in the direction indicated.
Installing the Humidier Pan (Model 55)
Attach the humidier housing (i.e., the pan) to the mounting frame by
inserting hinge pins into the mated hinge halves.
Place the evaporator pad between the two guide rails in the bottom of
the pan, then place the pad frame/drip tray assembly over the evapo-
rator pad, with the rubber grommet facing you. Insert the rubber water
tube into the rubber grommet, as shown in Figure 12, below.
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AIR FLOW
FIGURE 12: Insertion of Model 55 Evaporator Pad and Water Tube
Raise the unit into a closed position and securely fasten in place, as
shown in Figure 13 (page 12).
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Page 12
AIR FLOW
FIGURE 13: Final Positioning of Model 55
Installing the Humidier Pan (Model 86)
To install the drum assembly, insert the drum shaft through the evapo-
rator pad and drum ends, then into the round bearing in the side of the
pan, as shown in Figure 14, below. (You’ll need to apply some force to
deect the retaining spring on the outside of the pan.) Insert the drum
shaft into the slotted opening in the motor coupling.
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FIGURE 14: Insertion of Model 86 Drum Assembly

Page 13
Install the bafe in the inside of the ductwork, as shown in Figure 15,
below. Reaching through the hole previously cut in the bottom of the
duct, mark two holes on the top inside of the duct by holding the bafe
in place about 6" (15.24 cm) from the side of the opening, then drill two
holes 7/64" (0.28 cm) in diameter through the top inside of the duct
and attach with two #8 sheet metal screws.
2.
FIGURE 15: Installation of Bafe in Duct
Follow these steps to properly plumb the Model 86 humidier:
A. At the cold water pipe you located earlier, install the saddle
connector and needle valve by following the instructions included
in the valve package. (This is a self-piercing unit when installed
on copper pipe.) To reduce the chance of minerals and other
contaminants from obstructing water ow, mount the valve so that
water will come from the top or side of the pipe.
WARNING: Use extreme caution to avoid selecting
an air conditioning line.
NOTE: Either hard or soft water may be used. Soft
water will require more maintenance (see page 17),
but cleaning will be easier.
B. Follow these important plumbing tips:
1) Lightly clean the tubing ends with ne sandpaper before
making any connections.
2) Fully insert the tubing into the valve ttings and tighten the
compression nut. Do not over-tighten. Moderate tightness
should prevent leaking. (Use the brass ttings provided.)
3.

Page 14
C. After attaching the tubing to the saddle valve, thoroughly ush the
supply tubing to clear the line of debris, which could block water
ow at the oat valve.
D. Route the tubing to the humidier oat valve.
CAUTION: Be sure to keep the tubing off of hot sur-
faces and away from sharp edges.
E. Connect the waterline.
1) For Model 55, connect the waterline as shown in Figure 16,
below.
NOTE: Pay close attention to the proper orienta-
tion of parts for assembly and disassembly. This
will assist you when cleaning the orice tting and
evaporator pad.
FIGURE 16: Waterline Connection for Model 55
2) For Model 86, connect the waterline by following the instruc-
tions for copper tubing, found in the parts bag.
F. Check the tubing for leaks. Stop leaks by further tightening the
ttings.
Prior to mounting the pan on the duct, set the pan on a at surface
to check and adjust the water level to approximately 2" (5.08 cm), as
shown in Figure 17 (page 15.).
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Page 15
FIGURE 17: Water Level Adjustment for Model 86
Attach the humidier housing (i.e., the pan) to the mounting frame by
inserting the hinge pins in the mated hinge halves.
Raise the unit into its closed position and securely fasten it in place.
Test the humidier for proper operation by activating the furnace
blower.
Installing the Drain Tubing
Models 55 and 86
Attach vinyl drain tubing (1/2" [1.27 cm] I.D., not supplied) with a clamp.
Run the tubing in a continuously downward direction to an adequate drain.
Make sure there is nothing to inhibit the ow of water.
CAUTION: Do not allow drain tubing to touch any heated
surfaces or sharp edges.
NOTE: See separate instructions for installing the humidi-
stat and transformer.
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Page 16
How to Operate Your Humidier
Your humidier’s output is controlled by a humidistat which monitors the
relative humidity in your home, and activates or deactivates the humidier
accordingly. It is installed either on the cold air return of your HVAC system
or on an interior wall of your home.
Refer to the chart below for recommended humidistat settings. Notice that
the settings increase as the outdoor temperature rises. This is to guard
against condensation. (See FAQs on page 24.)
Outdoor Recommended Outdoor Recommended
Temperature Setting Temperature Setting
-20°F (-29°C) 15 +10°F (-12°C) 30
-10°F (-23°C) 20 +20°F (-7°C) 35
0°F (-18°C) 25 Above 20°F (-7°C) 40
Your humidifier may be equipped with a humidistat that has different
relative humidity settings than those shown above. If so, use the following
recommended settings:
Outdoor Humidity
Temperature Setting
-20°F (-29°C) Low
-10°F (-23°C) Low
0°F (-18°C) Med
+10°F (-12°C) Med
+20°F (-7°C) High
Above 20°F (-7°C) High
An unusually high frequency or prolonged period of indoor activities such as
showering, cooking, clothes drying, etc., may cause indoor humidity to rise
to an excessive level, causing condensation to accumulate on windows.
If this condition lasts for more than a few hours, turn your humidifier off
until normal indoor activity resumes. If the condition persists, you should
ventilate your home to remove excess moisture.

Page 17
How to Maintain Your Humidier
DANGER: To avoid electrical shock or burn, turn
off the power supplying this equipment before
servicing.
To maintain high evaporating efciency of your Model 55 or Model 86
humidier, replace the evaporator pad at least once a year (e.g., at the end
of each heating/humidifying season). In hard water areas, cleaning may
be required every three-to-four weeks; in soft water areas, cleaning may
be required every four-to-eight weeks.
At the end of each humidication season (i.e., in the spring), clean the
humidier thoroughly, and turn off the water and electrical power to the unit
until the following season.
CAUTION: Do not leave water in the humidier pan
over the non-humidifying months!
For standard maintenance of Model 55, follow these instructions:
Shut off the water supply.
Lift out the distribution tray and evaporator pad assembly by reversing
the procedure found in #2 under “Installing the Humidier Pan (Model
55)”, page 11.
Wash all plastic and metal parts (except electrical parts) in humidier
cleaner or a 50/50 solution of vinegar and water. Rinse all parts
thoroughly with fresh water.
Wipe loose sediment from the water tray.
CAUTION: Make sure no particles are allowed to plug
the drain hole.
Replace the evaporator pad.
NOTE: Annual replacement of the evaporator pad is
recommended. Severe clogging of the pores may require
replacing the pad more frequently.
Restore the humidier to automatic operation mode by following the
nal assembly instructions for Model 55 on page 11.
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Page 18
For standard maintenance of Model 86, follow these instructions:
Shut off the water supply and drain the unit by removing the threaded
plug in the bottom of the humidier.
Remove the drum and disassemble the unit by reversing the nal
assembly instructions for Model 86 on page 12.
Remove the evaporator pad from the drum by squeezing the nger
prongs on the clip, holding the drum end in place and pulling. (See
Figure 19, page 20.)
Clean all non-electrical parts with humidier cleaner or a 50/50 solution
of vinegar and water. Rinse all parts thoroughly with fresh water before
putting the unit back into operation.
Discard the water in the water pan and remove mineral deposits from
the bottom of the pan. Clean mineral deposits from around the water
valve. When reversing or replacing the rubber valve seat, be sure
the rubber is facing the valve jet opening. Turn the adjustment screw
clockwise () to lower, or turn it counterclockwise () to increase the
water level.
Model 55 Parts List
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FIGURE 18: Model 55 Parts