Carrier 40QQ Series Installation Instructions Manual

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12Positioning on Curb —Position the unit on the roof curb so that the followingclearances are maintained:S 1/4 inch (6.4 mm) clearance between the roof curb andthe base rail inside the front and rearS 0.0 inch clearance between the roof curb and the baserail inside on the duct end of the unitThis will result in the distance between the roof curb andthe base rail inside on the control box end of the unitbeing approximately 1/4 inch.Although the unit is weatherproof, guard against waterfrom higher level runoff and overhangs.After the unit is in position, remove the rigging skids andshipping materials.Step 7 — Convert to Horizontal and ConnectDuctwork (when required)The unit is shipped in the vertical duct configuration. Unitswithout the factory- installed economizer may befield- converted to horizontal ducted configuration. Toconvert to horizontal configuration, remove screws from theside duct opening covers and remove the covers. Using thesame screws, install the covers on vertical duct openingswith the insulation- side down. Seals around duct openingsmust be tight (See Fig. 9).Fig. 9 - Horizontal Conversion PanelsField- supplied flanges should be attached to horizontalduct openings, and all ductwork should be secured to theflanges. Insulate and weatherproof all external ductwork,joints, and roof or building openings with counter flashingand mastic in accordance with applicable codes.Do not cover or obscure visibility to the unit’s informativedata plate when insulating horizontal ductwork.Step 8 — Install External Condensate Trap andLineUnit has one 3/4 inch condensate drain connection on theend of the condensate pan and an alternate connection onthe bottom (See Fig. 10). Unit airflow configuration doesnot determine which drain connection to use. Either drainconnection can be used with vertical or horizontalapplications.DRAIN(FACTORY-INSTALLED)PLUGCONDENSATE PAN (SIDE VIEW)STANDARDSIDE DRAINALTERNATEBOTTOM DRAINFig. 10 - Condensate Drain Pan (Side View)To use the alternate bottom drain connection, remove thered drain plug from the bottom connection (use a 1/2 in.square socket drive extension), and install it in the sidedrain connection.The piping for the condensate drain and external trap canbe completed after the unit is in place (See Fig. 11).NOTE: Trap should be deep enough to offset maximum unit staticdifference. A 4” (102) trap is recommended.MINIMUM PITCH1” (25mm) PER10’ (3m) OF LINE BASE RAILOPENVENTTO ROOFDRAINDRAIN PLUGROOFCURBSEE NOTE2˝ (51) MINFig. 11 - Condensate Drain Piping DetailsAll units must have an external trap for condensatedrainage. Install a trap at least 4 inches (102 mm) deepand protect against freeze-up. If drain line is installeddownstream from external trap, pitch line away from theunit at 1 inch per 10 feet (25 mm per 3 m) of run. Do notuse a pipe size gsmaller than the unit connection (3/4inch).40QQ