When your RV's ducted air distribution starts underperforming, a cracked, warped, or missing duct collar is often the culprit. The Coleman Mach 8330-3501 is an OEM-specified replacement duct collar designed for select 8000 series rooftop air conditioners, restoring proper airflow routing from your AC unit into the RV's duct system.
The duct collar is the interface between your rooftop air conditioner and the ceiling duct system inside your RV. Over time, plastic duct collars can crack from UV exposure, vibration, or repeated heating and cooling cycles -- leading to air leaks that reduce cooling efficiency and waste energy. This Coleman Mach 8330-3501 collar is engineered to the same specifications as the original component, so you get a precise drop-in replacement without modification.
Part number 8330-3501 (vendor reference CMN8330-3501) is a genuine Coleman Mach accessory/replacement part. Always verify your specific unit's model number against Coleman Mach's parts compatibility list before ordering, as the 8000 series includes several variants with different duct configurations.
Engineered to original Coleman Mach tolerances for a precise, leak-free connection to your 8000 series AC unit.
Seals the transition between rooftop unit and interior duct system, recovering lost cooling efficiency.
Designed specifically for compatible Coleman Mach 8000 series rooftop air conditioner models.
Replaces worn, cracked, or missing original duct collar -- no cutting or adapter hardware required for correct-fitment units.
On ducted RV air conditioning systems, the duct collar mounts at the base of the rooftop AC unit and channels conditioned air into the ceiling plenum or duct runs that distribute cooling throughout the coach. A damaged or improperly seated collar allows conditioned air to bypass the duct system entirely -- dumping cold air into the ceiling cavity rather than into your living space. The result is longer run times, higher power draw, and uneven temperatures inside the RV.
Replacing a failed duct collar is one of the most cost-effective AC repairs you can make. It requires no refrigerant handling, no electrical work, and typically no special tools -- just removing the interior AC shroud/ceiling assembly to access the collar mounting location.
Part number 8330-3501 is a Coleman Mach OEM accessory. Using the correct OEM collar ensures the sealing surface geometry, mounting tab positions, and duct opening dimensions match your unit exactly -- aftermarket collars may not seal correctly on Coleman Mach units.
Duct collar replacement on a Coleman Mach 8000 series unit is typically a DIY-accessible repair:
The Coleman Mach 8000 series encompasses multiple BTU ratings and ducted/non-ducted configurations. This duct collar (8330-3501) is intended for specific ducted variants within that series. Confirm your unit's full model number matches before ordering. Your unit's model label is typically located on the outside of the rooftop shroud or on a label visible when the shroud is removed.
Not all Coleman Mach 8000 series units use the same duct collar. If your unit is non-ducted or uses a ceiling assembly duct collar (separate from the rooftop transition collar), verify part 8330-3501 is the correct component for your specific model before installation.
While the interior ceiling assembly is removed for this repair, inspect the foam gasket between the rooftop unit and the roof opening, the drain pan for cracks or standing water, and all visible wiring harness connections. Addressing multiple items in one access session saves significant labor time on future service calls.