2022+ Thor Omni cooling problems

[alphainfinity]

Hi all,

I am currently in the process of buying a 2023 Omni BT36 with the F600 chassis. I have read a few long threads here about Omni cooling issues with the dual 13.5 btu AC units and I was wondering if these issues have been resolved in the 2022+ Omni units? It looks like Thor is still selling the OMNI with 13.5k units. Our main concern is that our 5 year old will be sleeping in the area over the cab and we want to make sure that this coach has ample cooling capacity. We have owned 5th wheels, travel trailers and a class a diesel pusher, so this isn’t our first rodeo and we do understand that with limited insulation, there will be limitations. There is a difference though between limitations vs a design flaw where a coach can’t maintain a fairly decent differential between outside ambient vs internal coach temperature for its occupants.

Really appreciate the feedback from current owners.

[The Gritz Carlton]

Don't understand this huge coach getting saddled with 13.5's. Mine has dual 15's and never had an issue. Is this a supply and demand problem or does a couple hundred dollars really make a difference to them on a $250K coach? I would demand an upgrade. BTW, the insulation is all foam block and seems to work well...I've never felt "warm walls" or ceiling in the hottest of Florida. Is the generator still the QD6000 or have they downgraded it to a 5500?

[Judge]

Gritz’s Chateau Super C May be a bit better insulated than my SV34. Some areas in my coach do get pretty warm to touch…. and putting that huge piece of glass in the can-over may have been one of the all-time stupid design moves.

I would bet the house your unit will be no better than my 2020 SV34…. possibly not even as good if there has been no change in the COVID quality and workmanship that was bad enough in pre-COVID times when I got my SV34 in October 2019.

Here are my recommendations for the best cooling in the Omni / Magnitude. I would do these things even if you upgrade to the 15K units.

1. Purchase the WeatherTech Full Cab Sunshade for the windshield and the cab door windows.

2. Purchase Frost King Adhesive Duct Insulation and then get on the roof, take off both covers and insulate the evaporator box completely. If you think you need / want a SoftStart to run both A/C’s off 30A for some reason, install those before insulating the two units.

3. Get a long, thin and sharp serrated saw and take off all of the A/C vent covers around the coach. Then use the saw to smooth the insulation in the ceiling for better airflow. Use a shop vac to suck up as much as the loose insulation and construction debris in the openings as possible. You also may want to use some spray foam insulation in the two front and two rear vents to prevent cold air being pushed into the ceiling over the front and rear cap.

4. Remove the covers from both units in the ceiling and make sure the divider block is centered. Then use good quality duct tape to seal around the divider to keep the cold exhaust air from being sucked into the warm air return.

5. On the hottest days keep all the shades down. Keep the curtains closed at the can-over bunk because the cab-over is a very large heat source from the window and poor insulation. Make sure the WeatherTech Sun Shade is installed (sliver side out):

6. Don’t believe the thermostat temperature readings. Use how it “feels” and a digital thermometer in the center of the coach. The two temperature sensors are foolishly placed under the cabinets almost aginst the walls. They may read temps 5 - 10 degrees higher than the actual temps in the coach. For example, last year in Nashville the air temps wete in the mid-90’s with high humidity. The sun was beating on the side of the coach where the temperature sensors were installed. The thermostat read 80 inside the coach but I could tell it was much cooler from the feel. I put my digital thermometer on the kitchen counter and it read 69 degrees.

7. Never open the shade to the cab-over window. It will allow sun to overheat the coach. I also never open it because several people have had the motor or track fail and then the shade is stuck open. I had a motor fail just as I dropped the coach off for warranty work at the Thor Factory Service Center in Wakarusa. I’ll never open it again.


Do all those things and the A/C’s can usually keep up ok. They may never shut off but they will keep the coach reasonably cool on hot and humid days.

[The Gritz Carlton]

The build specifics change so much from year to year. The duct work in my ceiling is actually a formed aluminum channel welding into the framing. That must have been to expensive. The thermostat sensors are mounted under the cabinets...right next to the windows in the LR and BR...that areas stays hotter so A/C's never shut off or require continuous adjustments. That over cab window was a huge mistake made by someone who's never owned an RV. I'm glad I don't have it. There as are many small issues with mine as there are with post models. It would be nice if you could manage the build from frame up and pay what you want for quality build. Then, we would keep them forever.

[Judge]

Originally Posted by The Gritz Carlton

The build specifics change so much from year to year. The duct work in my ceiling is actually a formed aluminum channel welding into the framing. That must have been to expensive. The thermostat sensors are mounted under the cabinets...right next to the windows in the LR and BR...that areas stays hotter so A/C's never shut off or require continuous adjustments. That over cab window was a huge mistake made by someone who's never owned an RV. I'm glad I don't have it. There as are many small issues with mine as there are with post models. It would be nice if you could manage the build from frame up and pay what you want for quality build. Then, we would keep them forever.

Amen Gritz!

The ductwork should be aluminum as it is in most Super C’s but in the Omni / Magnitude they cut corners by using the styrofoam ceiling insulation as channels to mimic ducts and then just cut a hole in the insulation for the vent. Just terrible……

[chunker21]

I and others have made specific posts detailing the deficiencies to the A/C ducting, and heating ducting. If you have actually read any of them and still buy a omni/magnitude then you'll have no justification to complain later. Putting 2 13.5K in a coach that size is ridiculous and the coach insulation and associated leaky seams and front glass means if you go to the deep south, you will be uncomfortable. But it's purty ain't it.

EDIT adding; at night with some fans to circulate air the cabover might be comfortable. During the day with the sun shining on it, the cabover will be an oven even with the cover closed. The cap has no insulation.

[Scubawise]

Originally Posted by Judge

Gritz’s Chateau Super C May be a bit better insulated than my SV34. Some areas in my coach do get pretty warm to touch…. and putting that huge piece of glass in the can-over may have been one of the all-time stupid design moves.

I would bet the house your unit will be no better than my 2020 SV34…. possibly not even as good if there has been no change in the COVID quality and workmanship that was bad enough in pre-COVID times when I got my SV34 in October 2019.

Here are my recommendations for the best cooling in the Omni / Magnitude. I would do these things even if you upgrade to the 15K units.

1. Purchase the WeatherTech Full Cab Sunshade for the windshield and the cab door windows.

2. Purchase Frost King Adhesive Duct Insulation and then get on the roof, take off both covers and insulate the evaporator box completely. If you think you need / want a SoftStart to run both A/C’s off 30A for some reason, install those before insulating the two units.

3. Get a long, thin and sharp serrated saw and take off all of the A/C vent covers around the coach. Then use the saw to smooth the insulation in the ceiling for better airflow. Use a shop vac to suck up as much as the loose insulation and construction debris in the openings as possible. You also may want to use some spray foam insulation in the two front and two rear vents to prevent cold air being pushed into the ceiling over the front and rear cap.

4. Remove the covers from both units in the ceiling and make sure the divider block is centered. Then use good quality duct tape to seal around the divider to keep the cold exhaust air from being sucked into the warm air return.

5. On the hottest days keep all the shades down. Keep the curtains closed at the can-over bunk because the cab-over is a very large heat source from the window and poor insulation. Make sure the WeatherTech Sun Shade is installed (sliver side out):

6. Don’t believe the thermostat temperature readings. Use how it “feels” and a digital thermometer in the center of the coach. The two temperature sensors are foolishly placed under the cabinets almost aginst the walls. They may read temps 5 - 10 degrees higher than the actual temps in the coach. For example, last year in Nashville the air temps wete in the mid-90’s with high humidity. The sun was beating on the side of the coach where the temperature sensors were installed. The thermostat read 80 inside the coach but I could tell it was much cooler from the feel. I put my digital thermometer on the kitchen counter and it read 69 degrees.

7. Never open the shade to the cab-over window. It will allow sun to overheat the coach. I also never open it because several people have had the motor or track fail and then the shade is stuck open. I had a motor fail just as I dropped the coach off for warranty work at the Thor Factory Service Center in Wakarusa. I’ll never open it again.


Do all those things and the A/C’s can usually keep up ok. They may never shut off but they will keep the coach reasonably cool on hot and humid days.

Is there a youtibe link vedio showing exactly what box to cover?

Purchase Frost King Adhesive Duct Insulation and then get on the roof, take off both covers and insulate the evaporator box completely. If you think you need / want a SoftStart to run both A/C’s off 30A for some reason, install those before insulating the two units.

[chunker21]

Originally Posted by Judge

Gritz’s Chateau Super C May be a bit better insulated than my SV34. Some areas in my coach do get pretty warm to touch…. and putting that huge piece of glass in the can-over may have been one of the all-time stupid design moves.

I would bet the house your unit will be no better than my 2020 SV34…. possibly not even as good if there has been no change in the COVID quality and workmanship that was bad enough in pre-COVID times when I got my SV34 in October 2019.

Here are my recommendations for the best cooling in the Omni / Magnitude. I would do these things even if you upgrade to the 15K units.

1. Purchase the WeatherTech Full Cab Sunshade for the windshield and the cab door windows.

2. Purchase Frost King Adhesive Duct Insulation and then get on the roof, take off both covers and insulate the evaporator box completely. If you think you need / want a SoftStart to run both A/C’s off 30A for some reason, install those before insulating the two units.

3. Get a long, thin and sharp serrated saw and take off all of the A/C vent covers around the coach. Then use the saw to smooth the insulation in the ceiling for better airflow. Use a shop vac to suck up as much as the loose insulation and construction debris in the openings as possible. You also may want to use some spray foam insulation in the two front and two rear vents to prevent cold air being pushed into the ceiling over the front and rear cap.

4. Remove the covers from both units in the ceiling and make sure the divider block is centered. Then use good quality duct tape to seal around the divider to keep the cold exhaust air from being sucked into the warm air return.

5. On the hottest days keep all the shades down. Keep the curtains closed at the can-over bunk because the cab-over is a very large heat source from the window and poor insulation. Make sure the WeatherTech Sun Shade is installed (sliver side out):

6. Don’t believe the thermostat temperature readings. Use how it “feels” and a digital thermometer in the center of the coach. The two temperature sensors are foolishly placed under the cabinets almost aginst the walls. They may read temps 5 - 10 degrees higher than the actual temps in the coach. For example, last year in Nashville the air temps wete in the mid-90’s with high humidity. The sun was beating on the side of the coach where the temperature sensors were installed. The thermostat read 80 inside the coach but I could tell it was much cooler from the feel. I put my digital thermometer on the kitchen counter and it read 69 degrees.

7. Never open the shade to the cab-over window. It will allow sun to overheat the coach. I also never open it because several people have had the motor or track fail and then the shade is stuck open. I had a motor fail just as I dropped the coach off for warranty work at the Thor Factory Service Center in Wakarusa. I’ll never open it again.


Do all those things and the A/C’s can usually keep up ok. They may never shut off but they will keep the coach reasonably cool on hot and humid days.

To add to judges list, start the A/C early and leave on. If you are gone during the day, leave them on. It's much easier to try to maintain temperature that try to lower it.

[Judge]

Originally Posted by Scubawise

Is there a youtibe link vedio showing exactly what box to cover?

Purchase Frost King Adhesive Duct Insulation and then get on the roof, take off both covers and insulate the evaporator box completely. If you think you need / want a SoftStart to run both A/C’s off 30A for some reason, install those before insulating the two units.

I didn’t creat a video but it’s pretty easy.

If you have a Coleman Mach A/C unit on the top of the roof there will be a plastic cover (roughly square) that is brown, white or black. Remove the cover after removing the four screws.

Once the cover is removed there is basically two sides to the A/C. One side has a fan and the condensor. The condesor has a honeycomb of cooling fins. By the way…. as part of your annual maintenance you should use some spray foaming cleaner on the condensor and then hose it off to remove any dirt, dead bugs, etc. so air can flow through it freely.

On the other side you will see a silver metal box. This is where the evaporator is located. There will also be some wires running inside of it (there is an access panel near the wires on the side where a SoftStart can be installed).

You then take the roll of the Frost King Insulation and start covering the metal enclosure/ box. I started to unroll the insulation and stuck one end on a flat surface and unrolled itnto the end of the other side. Then I would use scissors to cut it and start again until the entire box was covered. You’ll have to cut some small pieces to cover some parts of the box.

I also used a small piece of pipe insulation to cover the large tube running from the compressor to the evaporator.

This helps keep the cold insulated from the roof heat so it can cool as efficiently as possible.

[chunker21]

Originally Posted by Judge

I didn’t creat a video but it’s pretty easy.

If you have a Coleman Mach A/C unit on the top of the roof there will be a plastic cover (roughly square) that is brown, white or black. Remove the cover after removing the four screws.



This helps keep the cold insulated from the roof heat so it can cool as efficiently as possible.

Last summer on this forum there were some similar discussions and some links to threads that have pictures of the exact procedures you outline. Also links to threads that detail pictorially the securing of the divider and use of foil tape, home made versions of the "airflow", and streamlining and sealing the airbox.

[Scubawise]

Originally Posted by Judge

I didn’t creat a video but it’s pretty easy.

If you have a Coleman Mach A/C unit on the top of the roof there will be a plastic cover (roughly square) that is brown, white or black. Remove the cover after removing the four screws.

Once the cover is removed there is basically two sides to the A/C. One side has a fan and the condensor. The condesor has a honeycomb of cooling fins. By the way…. as part of your annual maintenance you should use some spray foaming cleaner on the condensor and then hose it off to remove any dirt, dead bugs, etc. so air can flow through it freely.

On the other side you will see a silver metal box. This is where the evaporator is located. There will also be some wires running inside of it (there is an access panel near the wires on the side where a SoftStart can be installed).

You then take the roll of the Frost King Insulation and start covering the metal enclosure/ box. I started to unroll the insulation and stuck one end on a flat surface and unrolled itnto the end of the other side. Then I would use scissors to cut it and start again until the entire box was covered. You’ll have to cut some small pieces to cover some parts of the box.

I also used a small piece of pipe insulation to cover the large tube running from the compressor to the evaporator.

This helps keep the cold insulated from the roof heat so it can cool as efficiently as possible.

Great information

Is this good for the Frost king?King??

Frost King Clear Plastic Weatherseal Tape, 2" x 100' https://www.amazon.com/dp/B000AYFPSI/ref=cm_sw_r_apan_i_D8BZKP3N2KTD9B2WB5XB


https://www.amazon.com/dp/B000AYFPSI...3N2KTD9B2WB5XB

[Scubawise]

Originally Posted by chunker21

Last summer on this forum there were some similar discussions and some links to threads that have pictures of the exact procedures you outline. Also links to threads that detail pictorially the securing of the divider and use of foil tape, home made versions of the "airflow", and streamlining and sealing the airbox.

Correct
I fixed my divider with recommended foil.
Did not remember top maintenance

[chunker21]

Originally Posted by Scubawise

Great information

Is this good for the Frost king?King??

Frost King Clear Plastic Weatherseal Tape, 2" x 100' https://www.amazon.com/dp/B000AYFPSI...3N2KTD9B2WB5XB


https://www.amazon.com/dp/B000AYFPSI...3N2KTD9B2WB5XB

Never used that. The standard for HVAC is foil tape which is available at your favorite hardware big box store.

[Scubawise]

Originally Posted by chunker21

Never used that. The standard for HVAC is foil tape which is available at your favorite hardware big box store.

Oh I have that used inside ..was not sure it could be used outside

150 Feet / 50 Yards] 1.9 inch Wide Aluminum Tape/Aluminum Foil Tape – Professional/Contractor-Grade - Ideal for Sealing & patching hot and Cold HVAC, Duct, Pipe, Insulation Home and Commercial https://www.amazon.com/dp/B01FROBUXE/ref=cm_sw_r_apan_i_9VWM05W7Q0D0MXHFTETF?_encoding= UTF8&psc=1

https://www.amazon.com/dp/B01FROBUXE...ing=UTF8&psc=1

[Judge]

Originally Posted by Scubawise

Great information

Is this good for the Frost king?King??

Frost King Clear Plastic Weatherseal Tape, 2" x 100' https://www.amazon.com/dp/B000AYFPSI...3N2KTD9B2WB5XB


https://www.amazon.com/dp/B000AYFPSI...3N2KTD9B2WB5XB

This is the Frost King Insulation I’m talking about to insulate the evaporator enclosure on the roof.

https://www.lowes.com/pd/Frost-King-...lation/1081449


Any good duct tape is good for sealing the plenum divider.

[Scubawise]

Originally Posted by Judge

This is the Frost King Insulation I’m talking about to insulate the evaporator enclosure on the roof.

https://www.lowes.com/pd/Frost-King-...lation/1081449


Any good duct tape is good for sealing the plenum divider.

Thanks got it

[Scubawise]

Originally Posted by Scubawise

Thanks got it

I can't find a vedio on where to apply this to the roof AC?

[chunker21]

Originally Posted by Scubawise

I can't find a vedio on where to apply this to the roof AC?

Last summer there were some A/C discussions and in one there was a link to another thread perhaps on a different forum. Will require some searching. The threads also had links to different threads where posters streamlined the airflow with the foil tape, secured the divider and a homemade version of the airflow device.

[EA37TS]

Originally Posted by Judge

This is the Frost King Insulation I’m talking about to insulate the evaporator enclosure on the roof.

https://www.lowes.com/pd/Frost-King-...lation/1081449


Any good duct tape is good for sealing the plenum divider.

Do not use duct tape in HVAC systems because it does not stand up to the extreme conditions of heating and cooling. Use either foil tape or duct mastic or HVAC systems.

Google ‘duct tape vs foil tape’ for all the reading you desire.

[Scubawise]

Originally Posted by chunker21

Last summer there were some A/C discussions and in one there was a link to another thread perhaps on a different forum. Will require some searching. The threads also had links to different threads where posters streamlined the airflow with the foil tape, secured the divider and a homemade version of the airflow device.

I did this part

streamlined the airflow with the foil tape, secured the divider