Improving AC Air Flow

Its common knowledge among vigilant and DIY RV'ers that the air conditioning units in RV's are not installed with much care and the ducting is not very efficient.

There is a product from RVAirflow that takes care of these deficiencies in one upgrade.

Like many RV-DIYers I decided to make and install my own. There are many versions of this mod on the Jayco RV forum such as this one: https://www.jaycoowners.com/forums/f64/seneca-a-c-airflow-mods-81502.html printed on a 3D printer.

My Unit, Better Than Most

I have to admit that I was surprised at how well my unit was taped when compared to pictures I had seen of other installs. 

Frankly, we did not think the noise was objectionable and the output at the vents seemed pretty strong. I decided to go for an improvement anyway.

A Different Material Than Most

After reviewing the other approaches to improving this ductwork I decided to use cardboard as the ducting material. Then while walking through Walmart I noticed the foam board and thought why not!

The Approach

I decided to try just cutting transition sheets from the foam board. These would be sections that would direct the air from the main output duct into the side ducts. I would use a combination of foam board and metalized ducting tape.

I decided to leave the stock centerpiece in place as it looked to provide a good seal.

Transitioning to The Side Ducts

I cut pieces of foam board that would fit from the source duct down to each of the ceiling's side plenums. I annotated the cut pieces with dimensions so that if you have the same unit they might keep you from fiddling to get a good fit.

Note that I cut the passenger piece on the wrong side of the material so it's installed with the blue backing outward.

These parts were taped in place with the Al tape insuring that all gaps and transitions were covered. Finish taping these parts fully before going to the next step.

The driver side

The passenger side. I cut this upside down.

Shows temp install .... before the final taping

First Section Taped

The Lower Baffles

Baffles were cut that provided the lower part of the new ducting. The apex of these two pieces fit against the center of the source opening splitting the airflow in 1/2. The dimensions for these pieces are also written on the part.

The passenger side to left

The driver side

Both installed 

Finishing The Install

The lower baffles are taped. Ensure that all the openings are taped shut. I taped the gaps at the edges near the ducts from the board to the frame to complete those transitions.

The Center Baffle

After assembly, I noticed that there was air leakage around the tape where it was applied to the center baffle. The tape does not stick to the stock center baffle material. Therefore I taped from the output side of the air conditioner down and around the center baffle and connected it to the input side which has a metal surface.

Fully Encapsulating the Center Baffle With Tape

Measurement Tool

I used an anemometer I bought from Amazon attached to a piece of 3/4" foam board to get a seal at each vent. 

Conclusions

In regard to using the foam board, I found it easy to cut and form with a sharp utility knife. It is also light, cheap, and readily available. The Al duct tape sticks to it well and it takes up less space.

I measured the airflow from each vent before I started. The airflow varied and it was hard to get a perfectly solid measurement. Later I discovered the AVG function on my meter, that would have been a better way to measure. In any case, I logged the most steady peak value for each vent.

I think there is enough improvement evident in the results below to consider this a worthwhile modification. I do not know if the results for Row 2 & 3 on the passenger side are the result of measurement error or what? In any case, one got a lot better and one did not change.

Enjoy and comment,

Don

Insulating the RV Doghouse

My wife and I insulated the floor of the cab in our 2019-20 Jayco 26Y last summer. We were quite pleased with the results. Much quieter and most importantly got rid of the "hot feet" on the passenger side. She is happy!

Some users reported that their doghouse got hot and even melted candy that was laying on its surface. We did not experience this problem with our RV.

We had plenty of the materials left over (Killomat) and decided to insulate the "doghouse".

This post summarizes that project.

The cab insulation project is here: https://www.jaycoowners.com/forums/f5/yet-another-post-about-sound-and-heat-abatement-2020-greyhawk-86233.html#post957747

Materials:

Killomat 50 mil: https://amzn.to/3iRFiRB. This was used on the cab floor and the leftover used on the doghouse.

Noico RED 150 mil: https://amzn.to/3hYAbPW. Used on the cab floor but not the Doghouse. I felt that the stock material and the Killomat would be enough sound and heat insulation for our needs. I also worried that three layers of material would be to thick and make reinstalling the doghouse difficult.

Tools

• Application Roller: https://amzn.to/3eKHxoq I bought this when we did the cab and found it to be a very useful tool to form and ensure the insulation fully adhered to the substrate
• Philips screwdriver
• Utility knife with a fresh blade
• Scissors
• Beer

Removal of the doghouse

The doghouse was removed by:

Remove the storage compartment that is on the front of the doghouse. I had no idea this compartment was removable. Getting it out of the way made getting the doghouse out from between the two seats much easier.

The compartment is affixed with two keyholes at the top and a clip at the bottom. When the clip is released the unit can be pulled upward and off.

To remove pull upward on the compartment while depressing the clip on the bottom of the assy. It's a bit "fiddly" but the key is to get the bottom clip to release the compartment so it can be lifted off.

Then release the locking arms at the upper and lower left and right of the doghouse and pull toward the rear of the RV and upward.

Notice the front storage compartment is removed

Remove the stock insulation

The stock insulation can be removed by freeing one edge and then systematically pulling the edges out from under the seal on the outer rim of the doghouse. The stock insulation is not glued in place but rather just held in place due to its form and the seal.

The stock insulation can be removed in one piece. Set it aside as we will replace it on top of the Killomat.

Do not remove the seal that is on the perimeter of the doghouse.

Install the Killomat Insulation

Clean the inner surface with alcohol or something that will remove any oils etc. Then systematically install the Killomat inside of the doghouse. You can fit each piece by placing it on the surface, with the backing on, and then press it in place to get it formed. Then cut it to shape. The Killomat cuts easily with a utility knife and scissors. 

Note: I left a 1-2" area at the edge of the seal free of Killomat. I did not want the thickness of the Killomat to inhibit installing the stock insulation back under the seal. This insured that the stock material was its original thickness as it is reinstalled under the seal.

The basic installation process is easy:

• Place the Killomat in its intended location and form it to the surface.
• Cut it to size. 
• Remove the backing. 
• Apply it to the surface. 
• Roll it on with the roller.

Killomat installed up to within 1-2" of the seal

Replace the Stock Insulation

After the Killomat is installed place the stock material over the top and fit the seal around the edges.

I used a Phillips head screwdriver to pull the seal up and over the edge of the stock insulation. Proceed around the perimeter of the doghouse until the entire edge of the stock insulation is under the seal.

The doghouse is now ready to re-install.

Reinstall the Doghouse Into the RV

Re-install the doghouse back into the RV

Reinstall the storage compartment onto the front of the doghouse. 

Enjoy the COOL & QUIET

Testing & Conclusions

I took 2 measurements with the sound meter on my phone. The first is at idle and the second is with the engine at 3000 RPM. The third measurement was previously made after the cab was insulated and running at idle. The apples-apples comparison is between the 1st and 3rd measurements.

The noise level measurement shows an improvement. I am not convinced that these measurements are consistent and accurate enough to make a conclusion about the value of insulating the doghouse. 

I have found that the real test is climbing up Parley's Canyon while the engine is groaning at 4000+ RPM and trying to have a conversation with the wife.

I don't know yet if this addition further reduced sound but it was easy to do and I had plenty of materials leftover from the cab insulation to do it.

I still have more material left. I plan to insulate the interface between the cab and the house. You will notice a step up from the cab to the house. This is a piece of fiberboard that is open to the road. Although I insulated it on the inside I plan to add insulation underneath and on the outside of this area.

Enjoy the Quiet

Don

Norco Refrigerator Door Hinge

Background

While surfing the Jayco RV Forums one morning I found out that the lower door hinge on my RV has the potential to crack under load and then the door falls off.

The section of the door frame that has the hinge pin integrated into it is not replaceable. Therefore the recommended fix is to replace the door which costs >$100. 

There is a bracket that can be purchased on Amazon; Norcold 634166 Door Hinge Kit. I do not know what model frig this fits but it did not fit my Norcold Polar 8 Series N8V, This bracket is offered by Norcold as a means of preventing the door from breaking. 

I have an N8X and that exact model # is not listed however the site says;

"This kit will only work on Norcold N6, N8, and N1095 models that have doors with a smooth interior texture. If your door is waffle in texture, this will not work on your hinge."

My frig is an N8V but I did not check my door's texture .... my bad!

There are multiple videos that show how to install the kit and also how to add a DIY bracket to the bottom frame. Some forum posts said this kit does not fit an N8, they were right.

Many RVers find out about this defect when their door falls off, often while on the road. Unfortunately, this may require a door replacement if the hinge cannot be glued back on. 

Don't think that just because you bought a new door this problem is fixed Norcold still wants you to add the $20 kit to your new door!?

To date, I have had no problem with my door but decided to inspect my lower hinge anyway.

At first, it appeared fine:

... then when I blew up the picture I could see that a crack was just starting to appear on the inside of the hinge pins plastic carrier.

The Door Hinge Kit

Norcold has a design defect in their product and they have the audacity to sell you a kit to fix it! Then the fix doesn't even fit. I have no idea how my model of frig is supposed to be fixed other than replacing the door. Lousy design fixed at the expense of customers seems to be an accepted practice in the RV market.

The kit comes with a left and right lower door hinge brace. It is intended to slide over and sandwich the frame adding support to the hinge pins housing.

It's apparent that it would not take much load to break the cantilevered pin housing with a fully loaded refer door. Add to that the shock loads an RV routinely endures and you have a likely failure at this hinge point. Seriously, $20 to fix a known design problem. 

What did not fit

I pushed the bracket over the frame as instructed. It would not fit. After careful inspection, I found that the slot in the bracket did not line up with a rib that was on the inside of the frame. Sigh, I guess I will modify the bracket and cut the slot wider...

After the surgery, the plate fits better over the frame but then it became apparent that it could not be pushed in far enough to engage the boss of the hinge pin.

This bracket was not going to work on my frig without major surgery. Those that said this kit did not fit my model had it right.... and now I knew why.

New Bracket Design

I think the idea behind the Norcold bracket's design was to sandwich the frame with a clamshell bracket thereby strengthening the pins carrier at the point of the cantilever. I figured this would work but I wondered what the screw holes were for? 

I realized that one way to fix this might be to use the face of the Norcold bracket and add a nut plate to the backside of the frame. This would accomplish the same as the Norcold design but with better fastening. Additionally reusing the purchased bracket somewhat relieved my frustration with wasting $20 on a useless part.

On YouTube, I also reviewed other designs where a plate was added underneath the door and screwed to the plastic frame with self-tapping screws.

Since reusing the Norcold bracket requires accurate fabrication it may not be practical to do in the field. Therefore I decided to use two approaches. Model 1 uses the bracket from the kit & Model 2 is an entirely new bracket whose design uses the profile of the Norcold bracket.

A template for both approaches is available in a 1:1 pdf file. If the .pdf file is printed 1:1 is should provide an accurate template to make these parts. 

It is possible to avoid buying the bracket for Model 1 by using the template to make a faceplate (A).

For reference here is a photo of the parts contained in the .pdf:

Get Brackets Template

Model 1

I knew the problem was going to be lining up the nut plate with the holes in the faceplate. For that reason, my plan was to make a separate nut plate and install it into the inside of the frame with the faceplate on the outside. Then while holding the faceplate in position, with a drill sized to fit the faceplate holes, drill pilot holes through the faceplate and the frame just marking the nut plate. This ensured that the threaded holes were accurately placed on the nut plate to match the faceplate.

Nut Plate (B)

The nut plate was made from a scrap piece of 3/32 Aluminum. A slot was cut with a hacksaw and widened with a Dremel tool. After marking the nut plate as described above, 6-32 screw holes were drilled and tapped at the marked positions. The screws had to be cut to about 15/32" in length otherwise they cannot be fully installed. 

Face Plate (A)

The faceplate was made by simply cutting the back portion of the Norcold bracket off with a Dremmel cutoff wheel. No other modifications were made to this plate.

Model A Installed

Model A was fabricated and installed successfully. We will see how it holds up over time.

Model 2

Although Model 1 results in a clean and effective fix (IMO), it has not been field-tested. Model 1 is also not practical to do in the field as accurate fabrication, drilling, and tapping are required. It's not likely that RVers are carrying those tools.

Model 2 is simpler to fabricate and install. I am keeping mine in the RV as a backup. I made mine from a steel shelf bracket because it is a readily available material that is thin and strong. It also has a shape that is close to what I had in mind for the bracket. Any metal type could be used but Aluminum may be easier to fabricate using hand tools. Either can be sourced from a nearby big-box store. Just ensure that it is thin enough to be used under the lower frame.

Model 2 also installs over the hinge pin boss. However, it is screwed to the bottom of the frame using self-tapping screws. I am not crazy about using self-tapping screws in plastic. This is why I prefer model 1 over model 2. 

The hinge pin hole was drilled out to 1/2" which is a bit too small to fit over the boss. A round file was used to open up the hole. 

There are 3 mounting screw holes which should be sized for whatever screws you have available.

Ensure that all burs and sharp edges are removed especially inside the 1/2" hole. This ensures that the bracket does not gaul anything. 

Washer

I installed the washer from the kit onto the hinge pin as instructed since the bracket takes up some room below the frame.

Sorry for the poor picture.

Tools/Parts

Model 1 & 2

• Drill
• Hacksaw
• File
• Screwdriver and or Nut driver

Model 1 only

• Dremmel cutoff wheel and tool
• Drill for 6-32 tap [# 36 drill, (.1065)]
• 6-32 Tap
• 3/32 metal (steel or aluminum) for Nut Plate
• Faceplate
• 2 x 6-32 screws

Model 2 Only

• 5/64 metal for the bracket; Al or steel (shelf bracket) 
• 2 x self-tapping screw
• Drill sized for self-tapping screw

Enjoy and please comment, 

Don