Styrofoam block in A/C unit?

[Double Eagle]

I just picked-up a new 337 RLS with a Coleman Mach15 in the living room and a Coleman 13,500 BTU in the bedroom. I noticed on the living room A/C there is a plastic cover over the two discharge vents behind the cover on the ceiling. I pulled the cover off the ceiling and then removed the plastic cover blocking the discharge vents and found a large block of styrofoam blocking the discharge. I assume this is here to keep the air going to the ducted vents only.

I found a sheet with the owners manuals stating to keep the two discharge vents close and only use the ducts for maximum efficiency. My previous fifth wheel a/c was not blocked like that.

My question is it ok to remove the styrofoam block and has anyone done this? Thanks for any help.

[WhittleBurner]

I just picked a new 337 RLS with a Coleman Mach15 in the living room and a Coleman 13,500 BTU in the bedroom. I noticed on the living room A/C there is a plastic cover over the two discharge vents behind the cover on the ceiling. I pulled the cover off the ceiling and then removed the plastic cover blocking the discharge vents and found a large block of styrofoam blocking the discharge. I assume this is here to keep the air going to the ducted vents only.

I found a sheet with the owners manuals stating to keep the two discharge vents close and only use the ducts for maximum efficiency. My previous fifth wheel a/c was not blocked like that.

My question is it ok to remove the styrofoam block and has anyone done this? Thanks for any help.

I am not a technician so take my advice with a grain of salt. Members have stated on this forum that to cool down the quickest when walking into a hot trailer is to open those vents so they are dumping all the cool air into the room rather than the ducts. That will give you the quickest cooling. So yes I would think it would be ok to remove the coverings from the vents.

[TheLexx]

So long as your divider bar is positioned correctly, the unit should be working alright. Make sure the divider bar is positioned so that the cold air venting out is not mixed with the intake, or you lose efficiency.

[Double Eagle]

I found some information on the internet about he styrofoam block, apparently airexcel, who makes Coleman a/c’s just approved the use of these in their A/C’s, so they won’t void the warranty. It appears Grand Design is putting them in all new units that are 15 BTU. The block quiets the unit and increases airflow through the ducts, but you loose the air dump on the ceiling cover, unless you remove it.

[Double Eagle]

Here is information on the RV airflow product.

https://rvairflow.com/products/rvairflow-coleman

[TheLexx]

Ahh, this is the new product GD is installing on their trailers. For those of us who don't want to spend $180 per ac unit, folks have been performing this mod themselves with foamboard. I'm about to do it on my trailer.

These pics are from the Facebook GD Modifications Group.

You can make the foam box that isolates the cold air from the intake air, so that there is absolutely no mixing of the warm and cold air.


This is what it looks like after you put it together from foam board that's commonly available at any big box hardware store:


The box as it's about to be taped into place:


While you loose the ability to use the AC vent dump, folks who have performed the mod state that there is a massive increase in the airflow out of the ceiling vents that more than makes up for the loss of the vent dump.

[Double Eagle]

Thanks Lexx, that’s looks like how I will have fix the front bedroom A/C. I have a lot of air leaking out the air shower in the front. Which in my opinion defeats the purpose of Grand Design blocking the living room A/C and not the bedroom.

I called grand design to see if they may have forgot to put one in the bedroom and they stated They only put it in the living room a/c. Doesn’t make sense to me; if your trying to keep the air in the ducts seems like both should be blocked.

[gabathey]

Ahh, this is the new product GD is installing on their trailers. For those of us who don't want to spend $180 per ac unit, folks have been performing this mod themselves with foamboard. I'm about to do it on my trailer.

These pics are from the Facebook GD Modifications Group.

You can make the foam box that isolates the cold air from the intake air, so that there is absolutely no mixing of the warm and cold air.


This is what it looks like after you put it together from foam board that's commonly available at any big box hardware store:


The box as it's about to be taped into place:


While you loose the ability to use the AC vent dump, folks who have performed the mod state that there is a massive increase in the airflow out of the ceiling vents that more than makes up for the loss of the vent dump.

We just completed this very mod this week in a 2600RB. Made a HUGE difference in noise level and air flow to the rest of the trailer. We won't go back to using the air dumps. I'm glad GD is including this block with new units.

[TheLexx]

We just completed this very mod this week in a 2600RB. Made a HUGE difference in noise level and air flow to the rest of the trailer. We won't go back to using the air dumps. I'm glad GD is including this block with new units.

AWESOME! Hey, after I saw the pics of the actual RV AirFlow kit, I got to thinking. What if we added foam to the upper part of the plenum to build it down to almost the level of the racetrack duct entrance? Then you could fabricate a triangular piece that acts as a diverter of the air to the left and right racetrack entrances. From the bottom you build it up with foam board to make the air chamber very small which will force the air into the diverter and into the racetracks.

Here's a rough sketch looking at it from front to back of the trailer (cross section basically).

[gabathey]

AWESOME! Hey, after I saw the pics of the actual RV AirFlow kit, I got to thinking. What if we added foam to the upper part of the plenum to build it down to almost the level of the racetrack duct entrance? Then you could fabricate a triangular piece that acts as a diverter of the air to the left and right racetrack entrances. From the bottom you build it up with foam board to make the air chamber very small which will force the air into the diverter and into the racetracks.

Here's a rough sketch looking at it from front to back of the trailer (cross section basically).

Dan Anderson posted the below pic on the GD Owner's Modification Facebook page. Very similar to what you're showing.