Dometic Air Conditioner Issue

[Butchy]

Folks,
Here is a copy of an email I sent to Dometic about a problem with my rear AC unit. They have been VERY responsive but I do not think their solution of having the cover replaced (under warranty) will solve the problem. Has anyone else experienced this with a "Blizzard NXT" AC? I see that they have recently replaced the cover style so that water cannot leak as I describe below.

To Dometic:
I recently purchased a Montana 3160RL 5th wheel with two Dometic AC units. I have only been on two trips but on both The rear unit leaks water into the RV through the return ducts only after a rain storm. The dealer worked on it and said they tightened the mounting bolts but it still leaks. I hate to say this but I believe there is a design flaw with the cover of this model and inside housing. The clam shell cover is designed so that the top section fits inside the bottom section allowing rain to enter in the front of the unit. This water puddles up and seeps or is pulled under the inside foam housing. After performing a test with a garden hose I believe the vacuum created by the operation of the fan housing is sucking the water into the return chamber housing. Once inside the housing it has several paths to leak into the return duct.

Tests I have performed include spraying water around the front cover of the unit with the unit operating. Inside the RV you can hear water “gurgling” until you turn the unit off then a flood comes through the return ducts. Also in Florida today, and several times since I owned the RV, we had a heavy rain WITHOUT the unit running, no water inside…

[CaptnJohn]

When the last hurricane came through it brought a lot of wind with 11" of rain. When I checked the 5er I found maybe 3ozof water over 3 days that had dropped on the island from an AC vent. Could not find any in any other area. Have not been able to find any since or to replicate.

[Butchy]

I am convinced that my leak will occur any time during a rainstorm if the AC is running. The cover is designed improperly allowing water to leak into the cooling unit. If the fan is running the return section sucks the water inside the fan compartment and into the return duct. Dometic is going to replace the cover. I hope they send the new design that prevents the problem!


Sent from my iPad using Tapatalk

[CaptnJohn]

Mine was NOT running but in storage when the water was noticed.

[dglsrichmond64]

Hey Butchy, I have the same AC unit on my 16 3820FK. i had a Dometic tech look at mine, and my unit was not properly installed over the 14x14 hole 2 weeks ago it rained really hard and i had the rear AC on and the problem has not been resolved, it still leaks in through the cool air return if the AC is on.

[CaptnJohn]

When the last hurricane came through it brought a lot of wind with 11" of rain. When I checked the 5er I found maybe 3ozof water over 3 days that had dropped on the island from an AC vent. Could not find any in any other area. Have not been able to find any since or to replicate.

I found the same without the AC running ~~ 5er was in storage. Wind / rain combo is all I could come up with.

[Bowlesj]

I have the fix for this problem. Dealers, Keystone, and Dometic are typically useless on this matter. Heartland, on the other hand has it figured out. I will post the whole thing as soon as I get to a PC.

A new top cover from Dometic would be nice as long as I don't have to haul the unit to a dealer.

John

2016 3820fk

[Bowlesj]

Atfeller,

You caught me at a good time, good internet!

Sorry your having trouble. I've got the post prepared below. Not sure if the pictures will post. If not, I may have to re-post or edit as required to get everything shown. The pics are important.

Start of copied MOC post starting now:

There are a variety of model numbers with this design. Ours is a 541916. I think the marketing name is Blizzard NXT 15,000BTU. The unit looks like this. This unit is typically installed in the rear position but I have worked on Heartlands that have them in both front and back. The only way to know you have water intrusion is to hose your A/C down and remove the inlet grills and filter. You can reach a finger into the outboard aft corners of the opening and feel for water but I recommend using a flashlight and mirror to have a peek in the duct. Have a bucket in place just in case.

https://photos.smugmug.com/Forums/i-q7xXGn3/0/O/541916.jpg

Water can get in from rain through the seam shown in the next image below. There is no flashing (overlap) designed into the top cover and rain can run directly into the inside bay where the A/C equipment resides. This in it's self would not be so bad as there are plenty of drain holes outside the roof seal. However, the designers failed to recognize that they have alternate mounting holes that can end up inside the return air duct on most installations.

https://photos.smugmug.com/Forums/i-7z3P4xH/0/L/IMG_0410-L.jpg

Dometic recommends sealing these mounting holes along with raising any harnesses in the area so they do not lay in puddles. All I have seen are fine on the harness. This work is accomplished after removing the forward styrofoam upper insulation and will require replacement of the sealing tape and putty. See the image below for the 2 areas as indicated by the 2 outboard arrows. The 2 inboard arrows mark the area where I do additional sealing as explained below. (Vehicle forward is down in the image.)

https://photos.smugmug.com/Forums/i-SPhXbDK/0/L/IMG_0576-L.jpg

I'll try to explain why you need to seal underneath, inside the duct as well as best I can. There are 2 layers of plastic here about 3/8" apart vertically. The mounting hole is drilled through both layers. Then a rivnut is installed in the top layer only and the lower shank of the rivnut protrudes into the lower hole but does not fill it. Water gets between these 2 layers and is able to drip past the rivnut shank into the bottom hole and thus into the return air duct. The RV techs I've spoke with have only sealed the upper hole and said they have had no returns. However, one tech that works at a dealer had the opportunity to test one after sealing and sure enough it was wet in the duct, much less but still wet. He convinced his boss to let him add the extra sealant I had discussed with him previously and further testing saw no water. I never advocate sealing a leak from the exit but you really have no choice on this case and there is very little pressure built up by the pooling water. So, in this last image you can see the additional silicone added to the underside of the mounting hole which is actually in the upper aft corner of the return duct. Hope this all makes some sense for those interested.

As far as warped roofs? Maybe, but this is a problem for sure if this A/C unit is installed.

John

https://photos.smugmug.com/Forums/i-2w6hvWh/0/L/IMG_0575-L.jpg

[Atfeller]

Atfeller,

You caught me at a good time, good internet!

Sorry your having trouble. I've got the post prepared below. Not sure if the pictures will post. If not, I may have to re-post or edit as required to get everything shown. The pics are important.

Start of copied MOC post starting now:

There are a variety of model numbers with this design. Ours is a 541916. I think the marketing name is Blizzard NXT 15,000BTU. The unit looks like this. This unit is typically installed in the rear position but I have worked on Heartlands that have them in both front and back. The only way to know you have water intrusion is to hose your A/C down and remove the inlet grills and filter. You can reach a finger into the outboard aft corners of the opening and feel for water but I recommend using a flashlight and mirror to have a peek in the duct. Have a bucket in place just in case.

https://john-njudy.smugmug.com/Forums/i-q7xXGn3/A

Water can get in from rain through the seam shown in the next image below. There is no flashing (overlap) designed into the top cover and rain can run directly into the inside bay where the A/C equipment resides. This in it's self would not be so bad as there are plenty of drain holes outside the roof seal. However, the designers failed to recognize that they have alternate mounting holes that can end up inside the return air duct on most installations.

https://john-njudy.smugmug.com/Forums/i-7z3P4xH/A

Dometic recommends sealing these mounting holes along with raising any harnesses in the area so they do not lay in puddles. All I have seen are fine on the harness. This work is accomplished after removing the forward styrofoam upper insulation and will require replacement of the sealing tape and putty. See the image below for the 2 areas as indicated by the 2 outboard arrows. The 2 inboard arrows mark the area where I do additional sealing as explained below. (Vehicle forward is down in the image.)

https://john-njudy.smugmug.com/Forums/i-SPhXbDK/A

I'll try to explain why you need to seal underneath, inside the duct as well as best I can. There are 2 layers of plastic here about 3/8" apart vertically. The mounting hole is drilled through both layers. Then a rivnut is installed in the top layer only and the lower shank of the rivnut protrudes into the lower hole but does not fill it. Water gets between these 2 layers and is able to drip past the rivnut shank into the bottom hole and thus into the return air duct. The RV techs I've spoke with have only sealed the upper hole and said they have had no returns. However, one tech that works at a dealer had the opportunity to test one after sealing and sure enough it was wet in the duct, much less but still wet. He convinced his boss to let him add the extra sealant I had discussed with him previously and further testing saw no water. I never advocate sealing a leak from the exit but you really have no choice on this case and there is very little pressure built up by the pooling water. So, in this last image you can see the additional silicone added to the underside of the mounting hole which is actually in the upper aft corner of the return duct. Hope this all makes some sense for those interested.

As far as warped roofs? Maybe, but this is a problem for sure if this A/C unit is installed.

John

https://john-njudy.smugmug.com/Forums/i-2w6hvWh/A
Thank you soo much... our rig is at the dealership again for the 3rd time, and they are scratching their heads... we have the fully ducted system and during heavy rain water comes through the ac intake...very frustrating... thankfully we keep our fifth wheel at our house so we can inspect.it every time we have a down pour... we ended up.having to.put a tarp over the ac to help prevent more water coming in...they said that the one mount bolt was a little loose but we still.kept getting water in the rig. Do you think that the cover too and how it fits could still be an issue..
Thanks again for the info
Alan

[Atfeller]

Hi John, sorry didn't see the pictures on the thread

[Bowlesj]

OK. Pics should be there now. (And now they are not! what the heck happened there? couple posts are completely gone.)

The cover is still a problem, but unless someone has tried drilling additional drain holes inside the perimeter of the A/C to roof seal, that won't matter.

Just to be extra safe, what I did is put some Gorilla tape over the seam on the forward portion of the A/C unit. In other words, flashed it as Dometic should have in the first place.

What the dealer has to do is look at penetrations to the A/C base inside the perimeter of the roof seal and make sure they are all 100% sealed. The extra gap around the rivnuts shocks everyone until I draw them a picture.

Good luck and pass it on. There are a lot of these units out there.

John 3820FK

[Atfeller]

Thanks so much John for posting the pictures. I also went on the other forum too and was shocked at how many other people have the same problem. The dealership did drill more holes the last go around but we still had water leaking during the last heavy rainfall. Waiting for the dealership to look at it again. They have had it over a week and still haven't looked at it and we have another heavy rainfall this weekend. Thankfully its covered and secured with tarp... I'm sure it must be coming from the gaps in the plastic that you had mentioned. So you put gorilla tape over the seam of the ac cover that covers the bottom cover correct? Thanks again for your help. Hopefully it will get fixed soon

[Bowlesj]

So you put gorilla tape over the seam of the ac cover that covers the bottom cover correct?

Yes, I did add the clear tape over the seam between the top and bottom cover as an extra precaution after I thoroughly water tested the sealant job. Some people I have helped have chose not to add the tape with no further problems but that equipment bay isn't designed to be a wet bay.


John

[Atfeller]

Hoping to get our camper back soon and will be testing it. Thanks again for your help. Much appreciated.

[Atfeller]

Got our camper back. Indeed John was right. Technician looked at the rivnut/bolts and saw where the bolts had started to turn rusty and could see where some of the water was entering the ac to the inside. Placed silicone as John described around bolts and underneath.
When I got the camper back I checked the clam cover and was amazed at the gaps between the bottom and top cover compared to the other ac at the front of our camper. Applied gorilla tape and will see if the problem is fixed in the next heavy rain. It's raining steady and light today and no problems so far. Keeping fingers crossed..
Check out the before and after pics of the seam gaps compared to the other ac at the front of our camper/bedroom area..
I will be contacting montana and dometic to advise of the design fault and see if this cover can be replaced.

[Atfeller]

Folks,
Here is a copy of an email I sent to Dometic about a problem with my rear AC unit. They have been VERY responsive but I do not think their solution of having the cover replaced (under warranty) will solve the problem. Has anyone else experienced this with a "Blizzard NXT" AC? I see that they have recently replaced the cover style so that water cannot leak as I describe below.

To Dometic:
I recently purchased a Montana 3160RL 5th wheel with two Dometic AC units. I have only been on two trips but on both The rear unit leaks water into the RV through the return ducts only after a rain storm. The dealer worked on it and said they tightened the mounting bolts but it still leaks. I hate to say this but I believe there is a design flaw with the cover of this model and inside housing. The clam shell cover is designed so that the top section fits inside the bottom section allowing rain to enter in the front of the unit. This water puddles up and seeps or is pulled under the inside foam housing. After performing a test with a garden hose I believe the vacuum created by the operation of the fan housing is sucking the water into the return chamber housing. Once inside the housing it has several paths to leak into the return duct.

Tests I have performed include spraying water around the front cover of the unit with the unit operating. Inside the RV you can hear water “gurgling” until you turn the unit off then a flood comes through the return ducts. Also in Florida today, and several times since I owned the RV, we had a heavy rain WITHOUT the unit running, no water inside…

You mentioned in your post that they have recently replaced the cover style for the ac. Would I contact the dealership to initiate the request or dometic themselves. Thanks

[Bowlesj]

Atfeller,

Glad to see it appears you have your leak stopped. Also, your tape job looks much better than mine:).

As far as the replacement cover. I just communicated today with Dometic customer support on the cover flashing. The rep said they have not redesigned this at all and the model in their showroom looks exactly like ours. Regardless, they said they will send a replacement cover in hopes it will fit better.

So, I am not sure what Butchy was talking about concerning an improved cover design, maybe a whole different A/C unit.

I am hopeful I can modify the new cover to add some sheet metal flashing with rivets and sealant. Might be tricky with all the compound curves but will see.

A lot of unanswered questions as far as WTH they were thinking but it doesn't seem like a fix is imminent.


John - 3820FK

[_MP_]

THANK YOU FOR THIS INFO! We purchased our 2017 3950BR in October, and had this happen to us today for the first time. AC was not running, but we had a drip from a screw head on one of the inside return vents. we have two of the Blizzard NXT 15k BTU units. I will try this fix when the rain stops.

This design flaw needs to be fixed ASAP.

[Butchy]

Read through this link.
http://www.keystoneforums.com/forums/showthread.php?p=217768

[battlebeetle]

Just finding this thread, although I am having the exact same problem with water leaking through the intake vents in my 2016 Montana. I took it to the dealership 8/2016 and they drilled the extra drain holes in the pan but it still leaks every time it rains and the AC is running and it's past the 1 year warranty now. Worried about long term water damage. Any updates on how well the posted fix in this thread has worked? Or any other fixes that worked? At this point I'm considering just ponying up for a new AC of a different brand.

Clay

[chuckster57]

Battlebeetle: first off welcome to the forum. I hope you can get your issue resolved, but if you do change A/C units to a different brand you will have to change the thermostat too.

[JRTJH]

Just ... I took it to the dealership 8/2016 and they drilled the extra drain holes in the pan but it still leaks every time it rains and the AC is running and it's past the 1 year warranty now...
Clay

Your trailer has a one year warranty, the air conditioner has a 2 year Dometic warranty. If the problem is the installation, that ends with the trailer's 1 year. If the problem is a defect with the A/C, it will be covered for another year. However I'd suspect that Dometic wouldn't consider water damage to be their responsibility. Either way, it's best to have your dealership fix it or replace it.

[Bowlesj]

Just finding this thread, although I am having the exact same problem with water leaking through the intake vents in my 2016 Montana. I took it to the dealership 8/2016 and they drilled the extra drain holes in the pan but it still leaks every time it rains and the AC is running and it's past the 1 year warranty now. Worried about long term water damage. Any updates on how well the posted fix in this thread has worked? Or any other fixes that worked? At this point I'm considering just ponying up for a new AC of a different brand.

Clay


I've now lost track of how many of these I've done. If you follow my instructions EXACTLY, there is no more water intrusion. This is even before adding tape to block rain water entrance. The tape was added as an extra precaution. The only area I have seen wet is the interior of the duct and the duct has always been sealed good enough to contain the water. Have seen no wet ceilings or insulation.

Drilling any extra drain holes is unecessary and Heartland has had some dealers go back and reseal the drilled drain holes. The 2 big issues is the scoop effect the 2 A/C halves have to channel the water in and then the extra mounting rivnut leaking into the coach interior.

Any tech that reads this thread and then cannot properly fix the problem is incompetent. Total time to complete if willing to remove the A/C styrofoam evaporator cover is 1 hour to repair, 2 hour cure, 30 minute leak check.

Dometic has sent me a new top cover and it fits no better than the originals.

If anyone has any improvements to this method, please advise.


John - 3820FK

[chuckster57]

What is the fix?

[Bowlesj]

What is the fix?

Posts #8 and #15 of this thread provide instructions with pictures to correct this problem.

John - 3820FK

[chuckster57]

Thanks. When I get time I'll look.

[battlebeetle]

I've now lost track of how many of these I've done. If you follow my instructions EXACTLY, there is no more water intrusion. This is even before adding tape to block rain water entrance. The tape was added as an extra precaution. The only area I have seen wet is the interior of the duct and the duct has always been sealed good enough to contain the water. Have seen no wet ceilings or insulation.

Drilling any extra drain holes is unecessary and Heartland has had some dealers go back and reseal the drilled drain holes. The 2 big issues is the scoop effect the 2 A/C halves have to channel the water in and then the extra mounting rivnut leaking into the coach interior.

Any tech that reads this thread and then cannot properly fix the problem is incompetent. Total time to complete if willing to remove the A/C styrofoam evaporator cover is 1 hour to repair, 2 hour cure, 30 minute leak check.

Dometic has sent me a new top cover and it fits no better than the originals.

If anyone has any improvements to this method, please advise.


John - 3820FK
Just following up on this thread and my experience.

After having the dealership complete the "fix" of drilling extra drain holes and plugging the holes where water leaks through the into the interior, the leaking through the intake vents (only when AC running while raining, no leaking while raining with AC off) was improved but still significant. After applying tape around the connection to the pan and lid, like in the pictures, the problem has gone away and I have had not more leakage through many storms over the past months with the AC running.

So, my logic leaves me to believe that there are 2 problems present: First, the bolt holes let water that has entered the pan front compartment run into the intake vents and enter the interior of the camper. Second, the suction created by the AC pulls standing water in the compartment up into the intake vents which then enters the camper. Plugging the holes takes are of problem one but not problem 2. Taping the lid/pan area takes care of problem 2. Both seems necessary for a complete fix. Just plugging the bolt holes did not solve the problem for me. Maybe it would solve the problem for new campers with lids that fit well, but once they get a little older and the lids become ill-fitting they may develop leaking problems again without the taping solution.

Thanks BowlesJ!

[Bowlesj]

Just following up on this thread and my experience.

After having the dealership complete the "fix" of drilling extra drain holes and plugging the holes where water leaks through the into the interior, the leaking through the intake vents (only when AC running while raining, no leaking while raining with AC off) was improved but still significant. After applying tape around the connection to the pan and lid, like in the pictures, the problem has gone away and I have had not more leakage through many storms over the past months with the AC running.

So, my logic leaves me to believe that there are 2 problems present: First, the bolt holes let water that has entered the pan front compartment run into the intake vents and enter the interior of the camper. Second, the suction created by the AC pulls standing water in the compartment up into the intake vents which then enters the camper. Plugging the holes takes are of problem one but not problem 2. Taping the lid/pan area takes care of problem 2. Both seems necessary for a complete fix. Just plugging the bolt holes did not solve the problem for me. Maybe it would solve the problem for new campers with lids that fit well, but once they get a little older and the lids become ill-fitting they may develop leaking problems again without the taping solution.

Thanks BowlesJ!


Since it sounds like a dealer, not yourself, did the repair, I'd have to see pics to believe they correctly sealed the exit of the rivnut in the upper fwd corner of the return duct. Unless you confirm you saw the final repair for yourself.

Regardless, I'm very pleased that you have things resolved to your "dry" satisfaction.

Happy camping.

John - 3820FK

[battlebeetle]

Since it sounds like a dealer, not yourself, did the repair, I'd have to see pics to believe they correctly sealed the exit of the rivnut in the upper fwd corner of the return duct. Unless you confirm you saw the final repair for yourself.

Regardless, I'm very pleased that you have things resolved to your "dry" satisfaction.

Happy camping.

John - 3820FK
The dealer did the repair, but I personally took off the styrofoam cover and inspected the rivnut exit you a referring to with a hand mirror and it was properly sealed. I even added some extra silicone sealant to all of the target holes for good measure. Your fix posting was spot-on.

[mmoff46]

Thankyou Bowlesj for the information. This was exactly what mine was doing and after taking it to the dealer and showing them the pics the leak was fixed. i had the research that I found through you or this probaly would not be fixed. thanks again.

[wiredgeorge]

Just finding this thread, although I am having the exact same problem with water leaking through the intake vents in my 2016 Montana. I took it to the dealership 8/2016 and they drilled the extra drain holes in the pan but it still leaks every time it rains and the AC is running and it's past the 1 year warranty now. Worried about long term water damage. Any updates on how well the posted fix in this thread has worked? Or any other fixes that worked? At this point I'm considering just ponying up for a new AC of a different brand.

Clay

Click on the name of the poster and then the "profile" and you will note the folks who had this discussion have not been back on this board for at least a couple years. I would head over to the Heartland forum that one of the posters mentioned and see if there is followup there on this issue. Sounds like some duct tape over the front seam and some silicon inside where it was indicated would be a fix.