Outdoor Unit Installation Details for CSAA/PSCA

Problem:

The Installation Operation Manual (IOM) for our product has become increasingly intricate and has undergone significant expansion since the initial launch of the Outdoor CSAA & PSCA product line. Given this complexity, we are seeking any additional guidance or instructions that could be provided to the contractors responsible for installation. The goal is to simplify the installation process and ensure that all necessary details are clear and comprehensible. Trane e-library CLCH-SVX016* CLCH-SVX018*; Public e-library CLCH-SVX016*  CLCH-SVX018*.

Solution:

This article aims to delve deeper into the variations present in the installation process to assist customers in effectively installing the outdoor CSAA/PSCA units. It is important to note that the installation process can vary significantly based on the size and configuration of the unit being installed. While the details provided in the IOM are generally accurate for most scenarios, the comprehensive nature of the manual—which includes information for all possible roof designs—can be overwhelming for installers. This complexity may lead to the potential oversight of critical details that are specifically relevant to the unit being installed. Therefore, it is essential to provide clearer guidance to help streamline the installation process.

Lifting: Follow all lifting guidelines and practices outlined in the equipment IOM. 

NOW AVAILABLE ON E-Library: Internal - CLCH-SVX024* Public - CLCH-SVX024*

Outdoor Section-to-Section Assembly
When it comes to the assembly of air handlers, they are shipped with all the necessary hardware for assembly, including butyl tape material. The assembly hardware is typically packaged in a clear plastic envelope or yellow bag(s), which can be found inside the fan section, access section, or mixing box of the unit. Due to the number of sections that often need to be assembled, it is common for the assembly materials to be distributed across multiple sections. Therefore, it is crucial to thoroughly inspect all sections of the shipment before reaching out to your Trane sales representative to report any missing items. This careful inspection process will help ensure that all components are accounted for, thus facilitating a smoother assembly and installation experience.

IOM:

KITS:

Sections are joined with butyl applied to one of the mating surfaces and hardware is used to bolt the sections together. 
 

To assemble the unit:

• Locate the mounting hardware and butyl material inside the unit.
• All shipping supports and crating on the face of the sections must be removed and discarded to permit proper fit-up and sealing of the surfaces. Remove any shipping bolts located on the mounting surfaces of the sections.
• Make all wiring connections for high and low voltage, in accordance with the IOM section-to-section quick connects detail. This must be completed before pulling the sections together, especially when there is no room to make the connections afterward, such as the case with back to back coil modules with no access door. It is impossible to make the connection once the sections are pulled together without disassembling a wall panel, which creates the opportunity for panel damage and leakage issues.

• For unit sizes 3-30, bolt the unit base frames together using 5/16-inch bolts.
• For unit sizes 35-120, bolt the unit base frames together using ½-threaded rod.
  • NOTE: READ the Unit Placement and Assembly - SHIPPING GUSSETS excerpt BEFORE the alignment process begins.

Threaded Bolt and Rod
Size 3-120 Outdoor: 0.500-13 X 10.5 in Threaded Rod (Qty. 1 per side)

Washer
Size 3-120 Outdoor: 0.656 ID X 0.312 OD Washer (Qty. 2 per side)

Nut
Size 3-120 Outdoor: 0.50 -13 NUT HEX FLANGE (Qty. 2 per side)

Wedge Block Installation

NOTE: Wedge block is being redesigned (09-02-25); Wedge Block (Information Only) Service Alert outlines Temporary Alignment Methods to use until the new wedge block kits are released to production Q1 2026.

The wedge block kit is designed to be used on unit size 40 thru 120. The kit include a set of offset wedge brackets that are attached to all four top corners of all sides of 2 adjacent shipping splits. The kits are intended for temporary alignment only during the joining process, so the kit will be used for all of the additional field joints as needed. The wedgeblock will interfere with proper sealing of the exterior seams, so it is not optional to leave in place. So discard the kit after use, or keep a set on standby if you install CSAA/PSCA outdoor units often. 

Overhang Removed for Clarity

LH WEDGE BLOCK ASSEMBLY

RH WEDGE BLOCK ASSEMBLY

• For sizes 66-120 only, bolt through the wedge blocks using a ½-threaded rod.
  Alternate between tightening on the lifting lug bolts and wedge block bolts until the shipping section comes
  together.
• Use straps and Come Along to compress the gasketing and pull the sections together along the height of the unit if the wedge block kit is not provided on size 3-30 as needed.
  Note: Wedge blocks are used to assemble shipping splits together unit size 35-120. Only one set of wedge blocks is shipped with each unit. Once the shipping split has been assembled, remove the wedge blocks and use for the next shipping split.

Crate Parts

The crated parts include seam caps, roof strips, c-channels, support brackets, stacked flashing, wide roof strips, etc. depending on the unit size and configuration.

Seam Cap Installation - Supporting Article Details

When installing outdoor air handlers, it is essential to note that they come equipped with a seam cap designed specifically to cover the seams between sections. This is a crucial step in ensuring the integrity and performance of the unit. Prior to applying the seam caps, it is necessary to use factory-supplied butyl tape. This tape must be applied continuously over the top and both side seams of the air handler. It is important to ensure that the butyl tape is applied as a single, uninterrupted layer, free from any tears or breaks, to maintain a proper seal.

Particular attention should be paid to the application of the butyl tape at the corners, especially where the roof meets the wall. It is vital that the tape does not end at this corner, as this area will not be covered by the seam cap. Instead, the butyl tape serves as the primary barrier against external rain infiltration, making its proper installation critical. For a better understanding of this process, please refer to the screenshot provided below, which illustrates the correct application of the seam cap and butyl tape.

Roof Panel Joint Variations

Unit Size 35 ( DSEQ L or Earlier Legacy), & Size 40 thru 120 - Support Article Details

The Wide Roof Strip is an essential component designed to effectively connect adjacent shipping split outer roof panels. This connection is crucial for forming a watertight seal along the roofline, which plays a significant role in managing rainwater and preventing leaks. For units sized between 50 and 120, it is necessary to utilize two wide roof strips to adequately cover the full width of the outer roof joint. In contrast, for unit size 40, only one wide roof strip is required to span the entire width of the roof.

• Cover the edges between adjacent overhangs along the vertical plane with field-supplied foil tape. This step serves a practical purpose by preventing birds and insects from entering the enclosed roof area. By sealing off these potential entry points, the foil tape helps to maintain a clean and pest-free environment, which is particularly important in areas where such issues could lead to further complications..
• The procedure for installing the wide roof strip is a meticulous process that begins with sliding the strip along the flange of the outer roof panels. This initial step is crucial as it sets the foundation for the entire installation. Once the strip has been positioned accurately, it is essential to manually form it down to ensure that it fits snugly against the overhang surface. This hand-formation is not merely a formality; it plays a significant role in achieving a secure and effective seal. In instances where there are alignment issues at the outer roof flanges, it is imperative to address these discrepancies before proceeding further with the installation. Proper alignment is vital because any misalignment at this stage can lead to complications down the line. Specifically, if the adjacent shipping splits are not aligned correctly, it could compromise the integrity of the weatherization function of the wide roof strips. Such failures could result in leaks or other forms of damage, undermining the effectiveness of the roofing system. Therefore, taking the time to ensure everything is aligned properly is essential for a successful installation and long-term performance of the roof.

• To further enhance the water management capabilities of the installation, it is required to apply two strips of white butyl tape along the vertical exposed edges of the outer roof panels. This additional layer serves a critical function;

• To secure the wide roof strip in place, screws are driven into the roof overhang, providing a stable and durable attachment. The attachment screws are provided in the ship with kit. This method not only enhances the structural integrity of the roof but also contributes to its overall weather resistance.  when the wide roof strip is affixed, the butyl tape that is installed creates a water dam effect, effectively preventing rainwater from seeping into the area below the roof. This proactive measure is vital for maintaining the integrity of the interior space and protecting it from potential water damage.

• When 2 piece wide roof strip is required, (size 50 and up) a bead of caulk (Manus Bond/Sika Brand equivalent) is required to seal the seam where the 2 wide strips meet along the roof.

• ** DO NOT install the wide roof strip with the screw holes located in the middle of the roof to screws down. This is a leak path that is counter to design intent and rain testing standards performed during engineering validation. 

Vertical Seam on Outer Roof Panels

• All vertical roof seams on the roof are to be sealed with a bead of caulk. The factory vertical seams in the outer roof panels should be sealed, but it is advised to check the entire unit roof to ensure it is sealed. Without this seal, the unit will be prone to water infiltration.

Unit Size CSAA 3-35 PSCA IW 27.5-96 inch - Support Article Details

This newer roof design was inspired by the UCCA outdoor roof design. Because CSAA offers multiple shipping splits, a section to section joint solution had to be created. The design engineers utilized a ship with C-Channel (PTAF perpendicular to air flow) design to interlock the adjacent shipping splits, and brackets with gaskets to seal the gutter system. The gutter effectively sheds water away from the top based on the integral sloped outer roof panels on each shipping split. One of the most notable differences between earlier roof designs are the integral build in overhang on the outer roof panel. This design enables less parts for the factory to manage and easier installation. 

C-Channel Installation

• The installation process for the c-channel involves sliding the channel from the side of the outer roof panel at the shipping split, after the shipping splits have been pulled together. Alignment must be good in order for these channels to fit. If there are roof elevation or issues with plum wall panel, they must be corrected before continuing with the installation.
• The c-channel should be flushed with the outer roof edge on the higher pitched side (High Side) of the outer roof based on horizontal plane.
• Fasten the c-channel to the shipping split outer roofs using the screws "HPU" .250-14 x .75 leached self driller with plastisol provided in the ship with kit.

Support Bracket Installation

• Make sure the appropriate support bracket gasket is used on the correct side. The gasket is vital for water management and longevity of the c-channel performance.
• Assemble the support bracket without notch and corresponding gasket for the High Side on the flush end of the c-channel and outer roof panels. Attach the assembly using the provided screws .250-14 x .75 leached self driller with plastisol.  
• Assemble the support bracket with notch and corresponding gasket for the Low Side on the overlapping outer roof panel end of the c-channel. Attached the assembly using the provided screws .250-14 x .75 leached self driller with plastisol.

STACKED UNIT ASSEMBLY

Trane Select Assist enables users to select stacked units for sizes ranging from CSAA 03 to 50, & PSCA 27.5 to 96 inch. It is crucial to adhere to the instructions provided in the Installation and Operation Manual (IOM) to ensure the proper preparation and installation of the second level section on top of the first level section. Before lifting any of the second level sections into place, it is essential that the first level is completely installed. This includes the energy wheel (EW), the Cool, Dry, Quiet (CDQ) wheel, and the Air-to-Air (ATA) sections. Only after the first level is fully assembled should you proceed with the installation of the upper sections.

• To create a reliable air seal between the upper and lower sections, it is necessary to apply a gasket measuring 1 inch thick and 4 inch wide on the roof of the lower section where the top level baserail meets it. This gasket is only required when the configuration is a single or shared air path between the two sections. It is important to ensure that the gasket is adequately compressed, as this will help establish a solid barrier against air leakage.
• Carefully lift the upper section according to the mechanical layout specified in the as-built submittals, positioning it on top of the lower section(s). This step requires attention to detail to ensure that the sections align properly and are positioned securely.
• Once the upper section is lifted into place, if there is an adjacent shipping split on the second level that includes lifting lugs, use the provided threaded rods to pull the sections together tightly at the lifting lugs, ensuring a snug fit. Note: it is crucial to install the white butyl tape according to standard installation practices before lifting sections in place.
• When applicable, utilize the wedge block kit for nominal unit sizes 35-50. It is advisable to use straps or clamps in conjunction with a wood cleat to protect the painted surfaces while aligning and pulling the top of the section together. This will help prevent any damage to the finish during the installation process.
• After sealing the sections with 1.5 inch wide gray butyl and the seam caps, the lifting lugs on the upper level section(s) should be removed. It is important to retain the lifting lug bolts and screws, as these will be required for the subsequent steps in the installation process.
• Once the lifting lugs have been removed, attach the stacking brackets that were provided with the ship with kits at the locations of the lifting lugs. Use the factory mounting hardware and any additional screws that may be necessary to secure the stacking brackets. The stacking brackets are powder-coated in black and are designed with an offset to align with the baserail of the upper section and the roofline of the lower section. It's important to note that additional stacking bracket requirements will be necessary at both the front and back of the unit for full-length design, or at either the front or back for units that are less than full length on the upper level.

The intricacies of installing vertical seam caps for stacked units are illustrated in the details provided below. These notes highlight the slight differences versus single level units. 

• When applying the 1.5-inch gray butyl for the lower section seam cap, it is essential to install it at least 1/2 inch below the wall panel of the second level. This precaution is necessary to ensure there is adequate space for the stacked flashing and butyl that will be installed in a later step. The gray butyl applied beneath the seam caps is too thick to fit under stacked flashing, so it will not compress properly under the stacked flashing, which will result in the flashing bowing outward and look aesthetically dysfunctional. This misalignment can potentially allow rainwater to infiltrate unsealed joints, leading to further complications.
• Additionally, make sure that the seam cap on the lower level extends at least 1 inch beyond the bottom of the wall panel seam into the base rail. This extension is critical for ensuring a secure and effective seal that will withstand environmental conditions.

STACKED FLASHING - Details

Stacked flashing comes standard on all outdoor CSAA/PSCA stacked units. The primary purpose is to seal the inherent gap between the lower section roof and upper section base rail. 

NOTE: Stacked Flashing (SFLASH_###) will be custom formulated parts numbers for every unit, so no 2 units in assembly, or even on a same order will be identical. 

• Apply gray butyl tape (.12 inch Tall x 1 inch Wide) to the perpendicular and direction of airflow flashing on all sections.
• Secure the flashing to the baserail using10-16 x .750 self driller provided in the stacked flashing kit. The flashing hole patterns should align with the hole pattern along the base rail of the upper level sections. There should be no reason to cut screw the flashing into place. If something is off, please contact technical support for help.
• For EW, CDQ, and ATA sections, preassemble end covers to the flashing with screws, before installing to the unit. 

Flashing Installation Location

Corner Seams

Seam Cover

End Guards

Used on EW, CDQ, & ATA sections, and at various locations on less then full length upper levels.

With Four Quadrant Doors

With Two Full Height Doors

Stacked Flashing Installation for Units with Upper Level Shorter Than The Lower Level

CSAA Size 40 & 50

This is the Wide Roof Strip roof style DSEQ L or earlier. 

• Ensure the lower level roof is caulked at the form horizontal seam.
• Bend the PTAF Stacked Flashing end tabs by hand or gently with channel locks/pliers to match the form on the DOAF stacked flashing mounted to the side of the unit. Underneath should be sealed with butyl tape where it mates.
• If the unit is a size 50, read instructions below ~ For unit size 50
• Secure the PTAF to the base rail with screws 10-16 x .750 self driller.
• Apply caulk to the exterior of the corner seam to ensure a water tight seal.

Example PTAF Stacked Flashing

• For unit size 50 with a two piece roof panel, additional sealing is required in the middle where the first level roof section meets with the second level baserail. Seal the vertical flanges of the roof with caulk prior to installing flashing. Once the flashing is installed, apply caulk to the joint, then install the direction of airflow roof strip and smooth caulk into crevices to ensure a water tight seal.

Important Stacked Flashing installation Notes

• Side Stacked Flashing will have locating features:
  • Right side front and back pieces will have two diamonds and a tab. Intermediate right side pieces (if present) will have two diamonds and the length of the part will match the ship group length and mounting holes will match the hole pattern on the unit.
  • Left side front and back pieces will have one diamond and a tab. Intermediate right side pieces (if present) will have two diamonds and the length of the part will match the ship group length and mounting holes will match the hole pattern on the unit.

• The stacked flashing runs full length on right/left sides of unit except on access side when an energy recovery section is present. For energy recovery and air-to-air sections without full height doors, flashing will extend to removable plug panel. For energy recovery section with full height doors, flashing will be flush with edge of vertical seam caps.
• Flashing runs the full length on the front/back of the unit. Front/back flashing will not have any locating features and will always have miter (one piece will have two miters, two pieces will have one miter)

CSAA Size 3 thru 35 & PSCA IW 27.5 thru 96 inch

Detail J - Stacked Outdoor Roof Panel Install

STEP 1

HIGH Side shown - Right Hand (RH) Drive Side in the details below

Assemble Skirt Support Bracket (Item 18) using Screw 10-16 x .750 self driller with Outdoor Roof Panel at HIGH Side of the lower level section. 

STEP 2

LOW SIDE shown - Right Hand (RH) Drive Side in the details below

Assemble Skirt Support Bracket (Item 19) using Screw 10-16 x .750 self driller with Outdoor Roof Panel at LOW Side of the lower level section. 

Pipe Cabinet Installation 

The pipe cabinet is an option that can be selected directly from the factory through the Trane Select Assist (TSA). This component is often referred to by various names, including dog house, pipe chase, service cabinet, or piping enclosure, reflecting its purpose and design in different contexts. External piping cabinets are specifically designed for outdoor units, serving the crucial function of protecting and enclosing the piping components associated with the access section. 

Note: When pipe cabinets are not selected, and factory valves are selected, the valves must be protected from the elements. We do not currently offer a weatherized coil valve assembly. Valve Weatherproofing

One notable feature of these cabinets is that the bottom is left open to facilitate roof penetration, ensuring that the installation process is as seamless as possible. In addition, the cabinets are equipped with maximum-sized doors that allow for easy access to the piping components when maintenance or inspection is required. If there are adjacent modules of the air handling unit that also have an external piping cabinet selected through the TSA, a single piping cabinet will be created to accommodate the piping components of all these adjacent modules. This design helps to streamline the installation and maintenance process, leading to a more efficient system overall. It is important to note that the maximum combined length of these pipe cabinets is 103 inches, which ensures that they can be effectively integrated into the overall system without compromising functionality. 

Furthermore, the foamed panel pipe cabinet assembly is not part of the airstream of the unit, meaning that it does not interfere with the airflow of the unit, nor should it be a source of sweating if properly installed. After the pipefitters have completed their work, it is the responsibility of the installing contractors to ensure that all piping penetrations are properly sealed and insulated. This step is crucial to maintaining the system's efficiency and preventing any potential issues related to air leaks or insulation failures. To assist with this process, the factory provides a neoprene grommet for all factory penetrations. This grommet adheres to the outer panel skin and fits snugly over the piping, when piping extends beyond the plane of the wall panel. Additionally, options for drain and vent holes can be selected through the TSA. However, it is important to note that if these holes are not selected, the grommets will not be included with the coil panel, which could impact the overall ease of interfacing the piping system to the coil.

Lifting Pipe Cabinets

• Ensure the pipe cabinet curb and pipe cabinet base are level and square. The cross member should be removed before pulling the pipe cabinet close to the air handler casing. The channel is attached with four bolts and nuts.
• Add 1 inch x 7.5 inch Armacell® gasketing to the inside of the pipe cabinet base rail. Add a continuous line of 3/8 inch x 3/8 inch white Butyl tape to the face of all surfaces on the pipe cabinet that will contact the unit when pulled tight. See the details in the illustrations below

Unit Size CSAA 3-35 PSCA IW 27.5-96 inch (C-Channel Style Roof)

Roof, Wall, Base Rail Butyl Application

• After all the gasket and butyl, are installed per the instructions above, Lift the pipe cabinet into place and attach the top roof flange with the #10-16 x .75 inch screws to the unit casing, after the steps below are completed.
• It will be necessary to pull the pipe cabinet tight to the unit casing using one of the outlined methods below depending on the pipe cabinet location on the unit based on unique design.

Unit Size CSAA 40-120 and PSCA IW 102-168 inch (Wide Roof Strip Style Roof)

Roof, Wall, Base Rail Butyl Application

• After all the gasket and butyl, are installed per the instructions above, Lift the pipe cabinet into place and attach the top roof flange with the #10-16 x .75 inch screws to the unit casing, after the steps below are completed.
• It will be necessary to pull the pipe cabinet tight to the unit casing using one or more of the outlined methods below depending on the pipe cabinet location on the unit based on unique design.

Pipe Cabinet to be Installed at Shipping Split Joint

• Remove the lifting lug screws and the lifting lug that is aligned with the pipe cabinet.
• Using the 3 screws from the unit lifting lug, install the Black Lug Replacement Plate (Item #7) in place of the unit lifting lug.
• Slide Pipe Cabinet Into Place, while leaving room to work.
• Turn the threaded rod (Item#4) provided in the pipe cabinet kit clockwise through the pipe cabinet lifting lug into the weld nut inside the base rail.
• Using the washer and nut on the end of the rod, turn the nut clockwise to pull the pipe cabinet tight against the unit.

Pipe Cabinet to be Attached to Unit Base Bracket

• Put the threaded rod (Item#4) provided in the pipe cabinet kit through the pipe cabinet lifting lug into the welded bracket on the unit base rail.
• Add the washers and nuts provided in the pipe cabinet kit on both ends of the threaded rod to pull the pipe cabinet tight against the unit.

Pipe Cabinet to be installed at Factory Joint

• Remove the lifting lug/splice plate screws that is aligned with the pipe cabinet lifting lug.
• Turn the threaded rod (Item#4) provided in the pipe cabinet kit clockwise through the pipe cabinet lifting lug into the weld nut inside the base rail.
• Using the washer and nut on the end of the rod, turn the nut clockwise to pull the pipe cabinet tight against the unit.

Pipe Cabinet Corner Cap Installation - Details

Pipe Cabinet corner caps are vital for sealing the exterior of the pipe cabinet to unit seam. Follow the instructions below to complete the installation of the 2 corner caps, per pipe cabinet. The pipe cabinet installation is not complete until the exterior is complete weather tight. 

• Add 3/8 inch x 3/8 inch white butyl tape to the corner cap on both sides that will touch the pipe cabinet and unit surface.
• Secure the corner cap on the inside corner with 10-16 x .750 self driller screws provided in the pipe cabinet ship with kit. 

Hood Installation

Outside Air (OA) Intake hoods and Exhaust Air (EA) hoods are selectable in TSA, or they can be field provided Hood Details. 

Below are some of the different types of hoods and installation details.

Lifting Hoods

• Per the mechanical layouts in the customer submittals package, determine where the OA or EA hoods are located on unit. Confirm the opening matches the hood received. The hoods should be labeled Inlet or Exhaust hood.
• The hood kit parts, includes grey butyl tape, which should be applied to the hood flange that has the attachment holes.
• Using the factory provided screws, mount the hoods to the unit in the correct location.
• In some cases the hoods may be large enough that they require support angles along the bottom that are attached to the baserail. On second level units, the support angles will penetrate the stacked flashing. The angles ship attached to the hood, but need to be secured below the hood to the air handler angle by the installing contractor. See Detail A below.
• EA side hoods are flippable by design and can be oriented to blow away from OA intake hoods.
• Multiple piece Standard Inlet Hood requires that the hoods are installed one at a time from bottom to top, so they can be lifted cleanly into place. Overlapping locations on the hoods should be sealed with butyl tape between the hoods.

Upper Level Hood Front/Back Mounted

Standard Inlet Hood (Multiple Pieces)

Outside Air (OA) Hood

The OA hoods may be mounted on the front or the back of the unit, or on the side of the unit. The OA hoods provide a means to controls the amount of fresh outside air being introduced into the system. Most codes require a minimum OA% for building occupancy. Consult with the local code and Authority Having Jurisdiction (AHJ) for minimum requirements. The specification may also be listed in the submittals package.

The OA hood from the factory comes with a standard removable Industrial EZ-KLEEN® moisture eliminator/permanent filter (UL certified Rated Velocity 150-900 fpm with Optimal Velocity 350-520 fpm). The eliminator filter track is covered on both sides of the hood assembly with a removable cover panel. 

Side Mounted

Back/Front Mounted

Exhaust Air (EA) Hood

The EA hoods may be mounted on the front or the back of the unit, or on the side of the unit. The exhaust hood(s) must be directed away from fresh air intake hoods (OA) to avoid recirculating exhausted air back into the system, which can set off alarms and greatly reduce IAQ standards. 

Side Mounted

Front/Back Mounted

Fan Section side discharge exhaust hood installation (intake hood shape varies)

WARNING:

Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.