One-piece precision die-cut EPDM sponge rubber plenum divider for RV roof-mounted A/C and heat pump units. Separates intake and return airflow chambers. Designed to work with Standard A/C Gasket Kit 70-3905-207. Hand crafted and made in USA.
The Steele Rubber Products 70-4284-207 is a precision die-cut EPDM sponge rubber plenum divider engineered specifically for RV roof-mounted air conditioning and heat pump units that require a physical separation between the intake and return airflow chambers. Many RV A/C units rely on this divider to maintain proper airflow routing through the ceiling assembly — without it, conditioned air re-circulates back into the A/C unit before it can reach the living space, resulting in reduced cooling output, weak airflow through the vents, and inefficient operation.
Manufactured from the same top-quality EPDM sponge rubber material used in the Steele Rubber Standard A/C Gasket Kit (70-3905-207), this plenum divider is purpose-built to work alongside that kit as the ideal supplement for units that require a dedicated intake-to-return divider piece. The one-piece, precision die-cut construction eliminates gaps and leak points that can occur with field-fabricated or multi-piece divider arrangements. The angled 1-1/2" x 1" profile fits the standard plenum channel geometry used on most roof-mounted RV A/C and heat pump units. Sourced to Steele Rubber's exact specifications, it is guaranteed to fit and backed by their 100% Satisfaction Guarantee.
Divides the A/C ceiling plenum into intake and return chambers so conditioned air flows through the living space rather than re-circulating
One-piece die-cut construction eliminates gaps and leak points that result from field-fabricated or multi-piece divider arrangements
Same top-quality material as the A/C Gasket Kit — UV, ozone, and weather-resistant for lasting performance in rooftop environments
Sourced to Steele Rubber Products' exact specifications — hand crafted with a 100% Satisfaction Guarantee
On RV roof-mounted A/C and heat pump units, the ceiling assembly contains a plenum — the air distribution chamber between the rooftop unit and the interior ceiling grille. In units designed with divided plenums, one side handles return air (warm cabin air drawn up into the A/C unit to be cooled) and the other side handles supply air (conditioned air blown back down into the living space). Without a divider: Return air and supply air mix in the plenum, creating a short-circuit loop where the A/C unit cools the same air repeatedly. The result is noticeably reduced airflow through the vents and poor cooling performance throughout the RV even when the compressor is running normally. With a properly installed divider: The intake and return chambers are fully separated. The A/C unit draws warm cabin air from one side, conditions it, and delivers cooled air back through the other side — producing maximum airflow and full cooling output. If your RV A/C seems weak or the airflow from the vents is noticeably less than it used to be, inspect the plenum divider before replacing the A/C unit itself. A missing, damaged, or improperly seated divider is a common and easily overlooked cause of poor A/C performance.
This plenum divider is designed as a supplement to the Standard A/C Gasket Kit 70-3905-207 and is intended for units that require a dedicated intake and return airflow divider piece. • Not all RV A/C units use a plenum divider. Check your existing ceiling assembly before ordering — if your unit does not have a divided plenum, this part is not needed • Match the old divider profile: Selecting the correct divider is as simple as matching the shape and dimensions of the original divider removed from your unit • Disconnect power first: Always disconnect power to the A/C unit before performing any work on the ceiling assembly or plenum The Standard A/C Gasket Kit 70-3905-207 also includes additional lengths of EPDM rubber that can be used as divider material or cut into additional leveling blocks — consult the kit contents before ordering this divider separately.
This plenum divider is designed to work with the Steele Rubber Standard A/C Gasket Kit 70-3905-207. If you are replacing your RV A/C gasket at the same time, the full kit includes: • One (1) 17" x 17" one-piece gasket (1" H x 1-1/2" W; 14" x 14" inside opening) • Two (2) leveling blocks (1-1/2" x 1" x 9") • One (1) straight divider strip (1-1/2" x 1" x 14") • One (1) angled divider strip (1-1/2" x 1" angled) • Pressure-sensitive adhesive backing • Installation instruction sheet The 70-4284-207 plenum divider is the angled strip sold separately for units that need a replacement divider without replacing the full gasket.
Before You Begin: • Disconnect all power to the A/C unit before working on the ceiling assembly • Have a helper available — working with the ceiling assembly is easier with two people Installation Steps: 1. Access the Plenum: Remove the interior A/C ceiling grille to access the plenum chamber 2. Identify Divider Location: Locate the channel in the plenum assembly where the divider seats to separate the intake and return sides 3. Remove Old Divider: Pull out the damaged or missing original divider piece 4. Clean the Channel: Remove any debris or residual material from the divider channel 5. Match Profile: Confirm the 1-1/2" x 1" angled profile of the 70-4284-207 matches the original divider shape 6. Seat the Divider: Press the new divider firmly into the plenum channel, ensuring full contact along its entire length 7. Reinstall Grille: Replace the ceiling grille and restore power — test A/C operation to confirm improved airflow
In The Package: • One (1) 70-4284-207 A/C Gasket Plenum Divider • One-piece angled EPDM sponge rubber strip (1-1/2" x 1" angled profile) Not Included: • Standard A/C Gasket Kit 70-3905-207 (sold separately — required if also replacing the roof gasket) • Installation tools
A properly installed plenum divider is one of the most overlooked factors in RV A/C performance. If the divider is missing, damaged, or has gaps from field-cutting, the A/C unit will appear to run normally while delivering noticeably reduced airflow and cooling capacity. Replacing it with a precision die-cut one-piece divider is a simple fix that can restore full A/C output without any other repairs.