McQuay Skyline OAH 003, Skyline OAC 004, Skyline OAC 003, Skyline OAH 004, Skyline OAH 006 Installation And Maintenance Manual
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Installation and Maintenance Manual IM777
Skyline Outdoor Air Handler
Sizes 003 - 055
Group: Applied AIr
Part Number: IM777
Date: April 2003
© 2003 McQuay International
IM777 Page 1
Table of Contents
Nomenclature ...................................................................... 2
General Information .................................. .......................... 3
Receiving and Handling .................................................. 3
Unit Storage .....................................................................3
Installation Guidelines ........................................................ 4
Service Clearances .......................................................... 4
Rigging ............................................................................ 4
Curb Mounting and Leveling .......................................... 5
Section Assembly ............................................................5
Access Doors and Panels ................................................. 6
Duct Connections ............................................................ 7
Dampers and Hoods ........................................................ 7
Mounting Actuators ......................................................... 8
Face and Bypass Section Mounting ................................ 8
Piping Vestibules ................................ ............................. 8
Piping and Coils ....................................... ....................... 8
Drain Pan Traps ............................................................. 11
Internal Isolation Assembly Adjustment .......................11
Nomenclature
OAH 003 F D A C
Electrical Installation .....................................................12
Operation Guidelines .........................................................13
Startup Checks ...............................................................13
Fan Wheel Alignment ....................................................14
Fan Operating Limits .....................................................16
Fan Vibration Levels ......................................................17
Service and Maintenance ..................................... ..............18
Periodic Service and Maintenance .................................18
Ball Bearing Lubrication ................................................18
Fan Drive Adjustments ..................................................18
Drive Belt Adjustment ...................................................21
Front Load Filter Option ................................................22
Winterizing Water Coils ................................................23
Coil Maintenance ...........................................................23
Component Removal & Replacement ...........................24
Warranty ............................................................................26
Warranty Return Material Procedure .............................26
Replacement Parts ..........................................................26
Model
OAH = Outdoor air handler
OAC = Outdoor component
Nominal Unit Size
(nominal square foot of coil)
003, 004, 006, 008, 010, 012,
014, 017, 021, 025, 030, 035, 045, 055
Vintage of McQuay Air Handling Unit
Unit Cross Section
C = Standard unit cross section
M = Custom size cross section
Motor Location
A = Motor along side of fan housing
D = Motor downstream of belt drive plenum fan
F = Motor on inline fan
G = Motor downstream of direct drive plenum fan
T = Motor behind twin housed fans
Unit T y pe/Co il Positi on
B = Blow-thru cooling coil location
D = Draw-thru cooling coil location
H = Heating only
V = Vent only
Page 2 IM777
General Information
The system design and installation must follow accepted
industry practice, such as described in the ASHRAE Handbook, the National Electric Code, and other applicable standards. The installation of this equipment must be in
accordance with regulations of authorities having jurisdiction and all applicable codes. It is the responsibility of
the installer to determine and follow the applicable codes.
Installation and maintenance must be performed by qualified personnel familiar with applicable codes and regulations, and experienced with this type of equipment. Sheet
metal parts, self-tapping screws, clips, and such items
inherently have sharp edges, and it is necessary that the
installer exercise caution.
CAUTION
SHARP EDGES AND COIL SURFACES
are a potential injury hazard. Avoid contact with them.
ATTENTION
Les bords tranchants et les surfaces des bobines sont un
risque de blessure. Ne les touchez pas.
Receiving and Handling
1. Carefully check items against the bills of lading to verify
all crates and cartons have been received. Carefully
inspect all units for shipping damage when received.
Report damage immediately and file a claim for damage
with the carrier.
2. Skyline air handler units are constructed of heavy-gauge
galvanized steel and are thoroughly inspected before leaving the factory. Care must be taken during installati on to
prevent damage to units.
3. Take special care when handling the blower section. All
fans are dynamically balanced before leaving the factory.
Rough handling can cause misalignment or a damaged
bearings or shaft. Carefully inspect fans and shaft before
unit installation to verify this has not happened.
4. If necessary, screws, bolts, etc., for assembly of sections
are supplied in a bag attached to each section. All necessary gasketing is applied in the factory for section to section mounting. Units require caulk sealant between
sections.
Unit Storage
Store unit on a level surface. If air handling units are to be
stored for any period of time, it is important to periodically
rotate the fan wheel. The fan wheel should be periodically
rotated to prevent permanent distortion of drive components. In
addition, grease may settle in the lower part of the bearing,
which may lead to oxidation on the upper portion of the bearing
surface. It is also important to keep the fan bearings lubricated.
IM777 Page 3
Installation Guidelines
Service Clearances
In addition to providing adequate space around the unit for
piping coils and drains, access is always required on at least
one side of the unit to allow for regular service and maintenance. Filter replacement, drain pan inspection and cleaning,
fan bearing lubrication and belt adjustment are examples of
routine maintenance that must be performed. Sufficient space
must also be provided on the side of the unit for shaft
removal and coil removal if necessary . Space at least equal to
the length of the coil is required for coil removal. Refer to the
"Coil data" section in Catalog 570 for information about coil
sizes. See Figure 1 for servicing space requirements.
At least 54" of clearance must be maintained in front of electrical power devices. Electrical power devices that are
mounted on the side of the unit are typically up to 12" deep.
See Figure 2.
Figure 1. Servicing space requirements
4.00" Lifting Bracket
Width
30.00"
4.00"
Width of coil section
30.00"
Width of
fan section
Figure 2. Service clearance for electrical power devices
1 2 "
5 4 "
Rigging
Skyline air handlers ship completely assembled, or in sections. The unit must be rigged as it ships from the factory.
Do not rig units after assembly. Unit s ar e p rovide d wit h a
factory installed base rail and can be lifted using the 2" diameter lifting holes located in the corners of each shipping section.
To prevent damage to the unit cabinetry, use spreader bars.
Spreader bars must be in position to stop cables from rubbing the frame or panels. Before hoisting into position, test
lift for stability and balance. Avoid twisting or uneven lifting of the unit.
Figure 3. Unit and section rigging
3
0
.
0
0
"
Page 4 IM777
Height
Curb Mounting and Leveling
Do not place a Skyline unit over an open curb unless it is
equipped with a curb-ready base. Installation instructions for
mounting units on a roof curb are provided in IM770. For a
copy , contact your local McQuay Representative or visit
www.mcquay.com. Make provisions under the unit to divert
any moisture from entering the building below.
For units without roof curb mounting, place the equipment on a flat and level surface. Where surface irregularities exist, shim the base of the unit at one or more points
along the length of the rails to prevent distortion or sagging. Uneven or distorted sections will cause misfit or
binding of the doors and panels and improper draining of
drain pans. See Figure 4.
Figure 5. Apply sealant to mating faces
1 / 4 " d i a m e t e r
b e a d c e n t e r e d
i n f a c e o f
c l e a r a n c e
U s e S p l i c e
J o i n t a s a
g u i d e
Figure 4. Leveling the unit
Shim sections until
they are straight
and level
Shim to prevent
distortion if width
is over 108"
Section Assembly
If the unit is shipped in more than one shipping section, rig
each section into position separately. Shipping sections are
provided with a connection splice joint attached on the leaving air side of the shipping section that seals against the
frame channel on the entering-air side of the adjoining section. The splice joint is insulated, and provides an air-tight
seal between two sections once they are assembled together.
The Splice Joint must be aligned to seat into the mating gasket to provide an air seal. If the Splice Joint was bent during
shipping or rigging, verify it is restored to its origin al position. Figure 6 on page 5.
2. Pull sections together to fasten. Use straps and a ratchet to
help pull the sections together securely. Apply sealant to
any gaps that may admit moisture.
3a.Fasten base rails together first using the 3/8"-16 by 5"
bolts found in the splice kit provided with the unit
See Figure 6. To fasten 2 shipping sections together, 4
bolts are needed (two on each side of the unit). The bolts
are run from one base rail into the other and fastened with
a nut. Complete each section bottom and top before
attaching additional sections.
Figure 6. Fasten bottom of section
Use the following procedure to assemble shipping sections:
1. Caulk all assembly joints of the unit. The mating faces of
the cabinet must have at least a 1/4 inch diameter bead of
sealant applied before the sections are joined. Use the
splice joint as a guide for application of the sealant. See
Figure 5.
IM777 Page 5
3 / 8 x 1 " B o l t a n d N u t
3b.If desired, shipping sections for non curb-ready units can
be fastened together internally. Internal fastening is
achieved by running field provided #10 sheet metal
screws or drill screws (4" long maximum) through the
interior frame channel of one unit into the splice joint of
the neighboring section.
Figure 7. Internal fastening
flanges. Bend the ends of the splice cap down to secure in
place. Assemble the small splice plate at the top rail to
secure the sections together at the top. Use 5/16" bolts.
See Figure 9.
Figure 9. Splice cap & splice plate
S l i d e S p l i c e C a p o n
a n d b e n d e n d s d o w n
Splice Collar
must be aligned
to seal to gasket.
A
View A
3c.Units with curb-ready ba ses and vesti bules must be han-
dled so that the lifting bracket can be removed after the
unit is placed on the curbing. Remove the lifting bracket
that projects inward over the curbing. Save the self tapping screws. When the adjacent section is placed in position, use self tapping screw to secure the bases together.
Figure 8. Remove vestibule lifting bracket
5 / 1 6 - 1 8 B o l t
5 / 1 6 - 1 8 N u t
S p l i c e
P l a t e
Access Doors and Panels
For routine maintenance, access is normally obtained through
access doors or by removing side panels. Removing all flat
head fasteners along the sides of a panel will allow it to be
removed.
Fan and filter sections are always provided with a service
door on one side of the unit. If requested on order, doors can
be provided on both sides of the unit. Optional service doors
are available for most section types, and are provided based
on customer request.
NOTE: Opening fan section doors requires the use of a 1/2"
socket wrench. This satisfies ANSI standards and other codes
that require the "use of tools" to access compartments containing moving parts or electrical wiring. See Figure 10.
1. Remove padlock if one is present.
CAUTION: DO NOT attempt to rotate the cup.
Damage to the unit will occur.
R e m o v a b l e
L i f t i n g B r a c k e t
4. Check that the sealant is compressed between the mating
channels when the unit sections are joined. Touch up any
places where gaps are noted. After sections are seated
tightly together, slip the splice cap over the top panel
Page 6 IM777
2. Insert 1/2" socket into cup and rotate 1/4 turn clockwise as
shown in Figure 10. If the cup and handle are on the left
side of the door, rotate 1/4 turn counter-clockwise.
3. Rotate door handle 1/4 turn clockwise, then 1/4 turn
counter-clockwise to release any internal pressure or vacuum and open the door. If the cup and handle are on the
left side of the door, rotate door handle 1/4 turn counterclockwise, then 1/4 turn clockwise.
4. To prevent air leakage, tighten the door panels by adjusting the jam nuts.
Figure 10. Opening fan section door
Figure 12. Flashing over top panels and sides of units
Do Not Rotate Cup
Jam
Nuts
View from inside door
OPEN
Duct Connections
Flexible connectors should be used on the outlet and inlet
duct connections of all units. Do not position down flow fans
over air ducts that are routed down into the building. A discharge plenum is recommended when bottom connections
are necessary. See Figure 11.
F l a s h i n g
D u c t
F l a s h i n g
D u c t
F l a s h i n g
U n i t t o p
p a n e l
F l a s h i n g
Dampers and Hoods
Side dampers may be provided in the mixing box and economizer sections of units. When dampers are provided, a
removable panel is located above the weather hood to provide access to the damper drive shaft. Other access may be
available depending on the specific construction of the unit.
See Figure 13.
Figure 13. Filler panel over the weather hood
Figure 11. Discharge plenum
D i s c h a r g e
P l e n u m
If the unit has a top mixing box or econo mi zer damper, or a
top duct connection, flashing mu st be field fabricated and
installed to divert moisture from the connection. The flashing
must lap over the standing seams of the top panels. The
flashing must also lap over the side edges of th e unit. See
Figure 12.
Remove screws
and panel to access
damper control shaft.
Hood
When units are ordered with exhaust hoods and intake hoods
adjacent to each other, a field supplied barrier is recommended to prevent re-circulation of exhaust air into the
intake openings. See Figure 14.
IM777 Page 7
Figure 14. Field installed barrier between hoods
I n t a k e
B a r r i e r
E x h a u s t
Mounting Actuators
The installing contractor is responsible for the mounting of all
field installed actuators. No provisions are made for the location of these actuators due to the number of options and
arrangements available and the variety of specific applications.
Ty pically, actu ators are mounted insi de the cabinet . Provide
proper support for the actuator to avoid excessive stress in the
cabinet, linkage, or damper shafts.
Piping Vestibules
The openings for routing the field piping must be cut as
required in the field for units that include a piping vestibule.
Carefully seal passages cut through the panels to prevent air
leakage. A single metal thickness pan is provided in the
bottom of the curb mounted vestibule. The pan can be
removed if necessary. If holes are cut into the pan for a piping
passage, seal the holes to prevent moisture leakage.
See Figure 15.
Figure 15. Seal holes for piping - curb mounted units
Seal Holes
Cut for Piping
Note: Damper blades are at full flow when open to 70
degrees. Do not open blades further than 70 degrees.
Fresh air and return air dampers can be linked together and
driven from the same actuator if the dampers are the same
size. If the dampers are different sizes, they must be driven
by separate actuators and controlled appropriately. Exhaust
dampers are always driven by a separate actuator.
A typical rotary electric actuator can handle up to 40 sq. ft. of
damper. For pneumatic actuators, allow 5 in-lb. per square
foot of damper area.
Face and Bypass Section Mounting
Internal and external face and bypass sections are mounted
together using the instructions for horizontal components and
do not require additional instruction. Skyline air handlers are
provided with a bypass duct that is integral to the unit construction and requires no field assembly.
Face and bypass dampers may or may not be linked together.
When dampers are placed before a single bank of coils, they
are always linked together and require a single actuator.
When dampers are bypassing a stacked or staggered coil, the
dampers are not linked and will require multiple actuators.
Face and bypass dampers have a torque requirement of 10 inlbs. per square foot of damper face area.
For units with standard base rails, the vestibule is open to the
coil section so all holes must be sealed to prevent air leakage.
Figure 16. Seal holes for piping - standard base rail units
Seal Holes
Cut for Piping
Piping and Coils
Follow applicable piping design, sizing, and installation
information presented in ASHRAE Handbooks in the design
and installation of piping. Observe all local codes and industry standards. Undue stress should not be applied at the connection to coil headers. Pipework should be supported
independently of the coils.
Page 8 IM777
Water Cooling Coils
Note:It is recommended that Glycol be used in water coils for
outdoor air handlers. Power failures and other mechanical issues can expose coil s to freezing temperatures.
1. Water supply, water return, drain, and vent connections
extend through the end panel of the coil section. All connections are labeled on the end panel.
2. Water supply and water return connections are typically
male N.P.T. iron pipe.
3. When installing couplings, do not apply undue stress to
the connection extending through unit panel. Use a
backup pipe wrench to avoid breaking the weld
between coil connection and header.
4. Follow recommendations of the control manufacturer
regarding types, sizing, and installation of controls.
Direct Expansion Coils
1. The coil distributor and suction connection extend
through the end panel of the coil section.
2. Check nozzle in distributor for proper tonnage.
3. When a thermostatic expansion valve is supplied with the
unit, it will be located outside the unit and connected
directly to the distributor (except on units with piping vestibules). Do not apply heat to the body of the expansion valve.
4. The thermostatic expansion valve must be of the external
equalizer tube type. Connect the 1/4-inch diameter external equalizer tube provided on the coil to connection on
expansion valve.
5. Use care when piping up the system to see that all joints
are tight and all lines are dry and free of foreign material. For typical refrigerant piping, see condensing unit
product manual.
Steam coils (refer to Figure 17 on page 10)
Note: Steam traps should not be placed outdoors.
1. All steam coils in units are pitched toward return
connection.
2. Steam supply and steam return connections are typically
male N.P.T. iron pipe and are labeled o n the en d panel of
coil section. Connections extend through coil section end
panel.
3. When installing couplings, do not apply undue stress to
the connection extending through unit panel. Use a
backup pipe wrench to avoid breaking the weld
between coil connection and header.
4. Support piping independently of coils and provide adequate piping flexibility. Stresses resulting from expansion
of closely coupled piping can cause serious damage.
5. Do not reduce pipe size at the coil return connection.
Carry return connection size through the dirt pocket, making the reduction at the branch leading to the trap.
6. Install vacuum breakers on all applications to prevent
retaining condensate in the coil. Generally, the vacuum
breaker is to be connected between the coil inlet and the
return main, the vacuum breaker should be open to the
atmosphere, and the trap design should allow venting of
large quantities of air.
7. Do not drip supply mains through the coil.
8. Do not attempt to lift condensate when using modulating
or on/off control.
9. Size traps in accordance with manufacturers' recommendations. Be certain that the required pressure differential
will always be available. Do not under-size.
10.Float and thermostatic or bucket traps are recommended
for low pressure steam. On high pressure steam, bucket
traps are normally recommended. Thermostatic traps
should be used only for air venting.
11.Bucket traps are recommended for use with on/off
control only.
12.Locate traps at least 12 inches below the coil return
connection.
13.Multiple coil installation.
a. Each coil or group of coils that is individually con-
trolled must be individually trapped.
b. Coils in series: Separate traps are required for each
coil, or bank of coils, in series.
c. Coils in parallel: A single trap may generally be used
but an individual trap for each coil is preferred.
d. Do not attempt to lift condensate when using modu lat-
ing or on/off control.
14.With coils arranged for series airflow a separate control is
required on each bank or coil in the direction of airflow.
15.Modulating steam valves are not recommended on high
pressure systems.
16.Modulating valves must be sized properly. Do not
under-size.
17.Freezing conditions (entering air temperatures below 35°F).
a. 5JA, 8JA, 5RA and 8RA coils are strongly recommended.
b. 5 psi steam must be supplied to coils at all times.
c. Modulating valves are not recommended. Control
should be provided by face and bypass dampers.
d. Consideration should be given to the use of two or three
coils in series with two position steam control valves on
that coil or coils which will be handling 35°F or colder
air. The desired degree of control can be at tain ed wit h a
modulating valve on the downstream coil.
e. Thoroughly mix fresh air and return air before it enters
the coil. Also, temperature control elements must be
properly located to obtain true air mixture temperatures.
f. As additional protection against freeze-up, the trap
should be installed sufficiently below coil to provide
an adequate hydrostatic head to provide removal of
condensate during an interruption in the steam pressure. Estimate three feet for each 1 psi of trap differential required.
g. On startup, admit steam to coil ten minutes before
admitting outdoor air.
h. Close fresh air dampers if steam supply pressure falls
below minimum specified.
IM777 Page 9
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