Unit installation
8 McQuay IM 777-3
Installation Guidelines
Injected-Foam Insulated Panels 
Skyline air handlers now are furnished with double-wall, 
injected-foam insulated panels. Foam panels are stronger, 
more rigid, and lighter than panels with fiberglass insulation. 
The insulation R-value is improved to 13. However, foam 
insulation can burn when exposed to flame or other ignition 
sources and release toxic fumes. Take care in cutting and 
sealing all field-cut openings in these panels.
Panel Cutting Procedure
1
Determine the number and location of holes required for 
electrical conduit, piping, and control wiring as follows:
• Check that adequate space is available inside the unit for 
conduit or pipe routing.
• Do not locate holes in a panel that provides access to key 
maintenance components such as filters and fan 
assemblies.
• Do not locate where the conduit or piping blocks airflow 
or obstructs hinged access doors.
2 Once a proper location is determined, drill a small pilot 
hole completely through the panel. Then use a sharp hole 
saw or a saber saw and cut from each side of the panel.
3 Seal the double-wall panel on each side with an industrial/
commercial grade silicone sealant or duct seal compound. 
It is extremely important to seal each panel hole or 
penetration securely so it is airtight, watertight, and so that 
there is no exposed insulation.
Figure 12: Cutting/Sealing Injected-Foam Insulated Panels
Field Mounting Junction Boxes and
Other Components
For field mounting 4" × 4" or smaller junction boxes to the 
standard panel exterior, use a minimum quantity of 4, 3/16" 
diameter pop rivets. Do not use self-tapping drill screws. 
They will not tighten nor secure properly and panel 
damage can occur.
If larger, heavier components require mounting on unit panels, 
use through-bolts with flat washers through both outer and 
inner panels. To maintain panel integrity, seal both ends with 
an industrial/commercial grade silicone sealant or duct seal 
compound.
The unit frame channel is another excellent location for 
securing heavier components; self-tapping screws are not 
acceptable. Ensure that the location permits the full operation 
of all access doors and panels and does not interfere with other 
vital components.
Duct Connections
Use flexible connectors on the outlet and inlet duct 
connections of all units. Do not position down flow fans over 
air ducts that are routed down intothe building. Use a 
discharge plenum when bottom connections are necessary. See 
Figure 13.
Figure 13: Discharge Plenum
WARNING
Flame and smoke can cause equipment 
damage, severe personal injury, or death.
Before operating unit, seal all piping and 
wiring holes on both inner and outer panels 
with an industrial grade silicone sealant or 
duct seal compound. Do not use a cutting 
torch or expose panel to fire. Panel 
damage can occur.
WARNING
La fumée et les flammes peuvent 
endommager le matériel et causesr des 
blessures graves ou la mort.
Avant d’utiliser le dispositif, obturer tous les 
trous de passage de tubulures et de fils 
ménagés dans les panneaux intérieurs et 
extérieurs au moyen d’une pâte à base de 
silicone ou d’un mastic d’étanchéite â 
conduits de qualité industrielle.
Ne pas se servir d’un chalumeau coupeur 
ni exposer les pannequx à une flamme 
nue pour ne pas risquer de les 
endommager.
Cut hole from both sides of panel
Seal completely with silicone 
sealant or duct seal compound
Prop 65—Substances in fuel or from fuel combustion can cause personal injury or death, 
and are known to the State of California to cause cancer, birth defects or other reproductive harm.
D i s c h a r g e
P l e n u m










