Added 3rd A/C to 389rd

[chop249]

Originally Posted by USNHMC8408RET

After getting my 3rd ac installed yesterday at the RV shop, I asked them about not getting ice. In my refrigerator -top / freezer-bottom, there is a hidden switch located behind a protruding bar on the 'ceiling' of the freezer section. No bale wire. You have to blindly reach and feel for the switch. Then, as suggested, there was also an on/off valve that is a 'push' tab to stop water or 'pull' to open it for water to go to the freezer. The Tech had a photo of each on his iPhone so that I could see what he was doing. Awesome guy.

3rd a.c. is awesome. Problem solved. Won't know until this weekend how cold I can get the inside temp to but it's suppose to be over 100 so we will see. I could have done this job myself but I'm glad I had them do it. The tech had a couple of issues to deal with that probably would have taken me much longer to figure out and I just didn't have time to do the fix myself. I had ordered all the parts myself to save money but couldn't get an a.c. unit here in time for me to leave on my trip. So, naturally I paid a fortune for the a.c. unit and hourly wage of the tech. It looks professionally done and I'm happy. End of that story.

Yeah sit isn’t a hard process to install it. It just takes time. Let us know how it goes.

[USNHMC8408RET]

Originally Posted by chop249

Yeah sit isn’t a hard process to install it. It just takes time. Let us know how it goes.

You're probably right.

I have installed 2 RV a.c. units personally in my younger days. Not hard to do unless it's 100 outside and your much older and shouldn't be climbing up on ladders risking heat stroke. lol

Well we are here at the campground and the 3rd a.c. has performed flawlessly. On this model there are maximum of 2 factory a.c.'s that could be ordered (2018 and older). As mentioned before, the 2019 models now offer 3 a.c.'s.

We arrived yesterday with an ambient temp of 96 with over 50 percent humidity a 'feels like' of over 100 degrees.

Fired all 3 units up and watched the clock/inside temp. Keep in mind this unit has 6 slides. 15 minute mark, noticeably cooler but inside temp still 96. Probably because the digital thermometer is a wall model so it takes time to cool off furniture and walls. At 30 we're at 94. At one hour we're at 84. At two hours we're at 80. At 3 hours we're at 76 and the furniture/walls/counters are noticeably cooler. The sun began to go down so of course the radiant outside heat was subsiding. The temp fell inside like a rock to 65 which is what it was set on.

Today, ambient outside temp is 95, feels like 106. Had to raise the temp on the 3 zones as I was cold with temp 65 inside. That's probably close to max of what the 3 zones can do in this particular situation.

The 3 a.c.'s now cycle in and out properly whereas before with just 2 a.c.'s they ran maxed out. I've got all 3 zones set to 67 today.

The locations of the original a.c.'s are at either end of the 42 feet plus rig. Putting the 3rd one in the middle with a dump was the trick. I have further tweaked my vents. 2 vents in the middle of the trailer have been blocked off now thus increase air flow in the other areas.

Worth the cost? Definitely. The idea of selling this model in the deep south with one a.c. is playing dirty. Selling with 2 a.c.'s is borderline dishonest. 3 a.c.'s is what the job requires and feels like a slice of heaven. Of course who knows, maybe my 379 FLOK is a lemon and I'm the only one with this issue in the deep south... I bet not. lol

P.S. A HUGE debt of gratitude to those trail blazers on this thread that took matters into their own hands and solved the problem!

[chop249]

Originally Posted by USNHMC8408RET

You're probably right.

I have installed 2 RV a.c. units personally in my younger days. Not hard to do unless it's 100 outside and your much older and shouldn't be climbing up on ladders risking heat stroke. lol

Well we are here at the campground and the 3rd a.c. has performed flawlessly. On this model there are maximum of 2 factory a.c.'s that could be ordered (2018 and older). As mentioned before, the 2019 models now offer 3 a.c.'s.

We arrived yesterday with an ambient temp of 96 with over 50 percent humidity a 'feels like' of over 100 degrees.

Fired all 3 units up and watched the clock/inside temp. Keep in mind this unit has 6 slides. 15 minute mark, noticeably cooler but inside temp still 96. Probably because the digital thermometer is a wall model so it takes time to cool off furniture and walls. At 30 we're at 94. At one hour we're at 84. At two hours we're at 80. At 3 hours we're at 76 and the furniture/walls/counters are noticeably cooler. The sun began to go down so of course the radiant outside heat was subsiding. The temp fell inside like a rock to 65 which is what it was set on.

Today, ambient outside temp is 95, feels like 106. Had to raise the temp on the 3 zones as I was cold with temp 65 inside. That's probably close to max of what the 3 zones can do in this particular situation.

The 3 a.c.'s now cycle in and out properly whereas before with just 2 a.c.'s they ran maxed out. I've got all 3 zones set to 67 today.

The locations of the original a.c.'s are at either end of the 42 feet plus rig. Putting the 3rd one in the middle with a dump was the trick. I have further tweaked my vents. 2 vents in the middle of the trailer have been blocked off now thus increase air flow in the other areas.

Worth the cost? Definitely. The idea of selling this model in the deep south with one a.c. is playing dirty. Selling with 2 a.c.'s is borderline dishonest. 3 a.c.'s is what the job requires and feels like a slice of heaven. Of course who knows, maybe my 379 FLOK is a lemon and I'm the only one with this issue in the deep south... I bet not. lol

P.S. A HUGE debt of gratitude to those trail blazers on this thread that took matters into their own hands and solved the problem!

Happy to hear it. I'm beginning to wonder if I don't need to replace my whisper quiet. I believe they said there were units that left the factory with less than the correct amount of coolant. However, and read this with HUGE air quote fingers, the dealers kept saying that it was within spec and putting out 20* cooler than ambient air.........

[USNHMC8408RET]

Originally Posted by chop249

Happy to hear it. I'm beginning to wonder if I don't need to replace my whisper quiet. I believe they said there were units that left the factory with less than the correct amount of coolant. However, and read this with HUGE air quote fingers, the dealers kept saying that it was within spec and putting out 20* cooler than ambient air.........

Any a.c. unit I've ever had trouble with in automobiles, the tech used a device that measures how cold it is at the vent. If working properly, it should be very cold, no matter what. I just had an a.c. fixed by a Ford dealership and that's how he tested it. It was nearly 100 that day but at the vent, it was very cold.

So if the unit is producing very cold air and the auto or camper etc. is not cooling off, its something else.

My sandpiper was a combination of not enough forced cold air volume and drafts around the slides plus severe radiant heating through all the many windows and slides on it. My a.c.'s are duotherm brisk air II, 15K BTU. Here is what I have: http://www.rvpartscountry.com/Dometi...0aAn0kEALw_wcB

Not sure if you've been near the factory but my brother-in-law stopped by the factory where they made his unit and got some tremendous feedback once they examined his camper.

It seems you've done everything to remedy the problem but I will tell you this, My a.c.'s blow Cold Air at the vents, not just 20 below outside ambient. In all my campers of the past this was true.

[koller1509]

Those are the same units I have as well.

[csterl01]

Originally Posted by brad2388

Ours came with 5 return vents two on the seach side and one in the middle. Ours also is cooling the air about 20 degrees but there just isnt enough to go around i suppose.

The new blizzard nxt i believe is at fault. The brisk air 2 blows about 7-8 degrees colder air than the blizzard. It will blow 50 degree air all day long with 76-78 air coming into it. Its also stronger as well.

I hope tomorrow i can finish the third ac install. Here is a list and some new pics of the install.




Sent from my iPhone using Tapatalk

How does the ductwork run in the ceiling? I have a 2016 Sierra 371 REBH with the bedroom in the front and living area in the rear. I saw you cut into the ductwork on the sides of the skylight; does the ductwork run right along side it? Is there a diagram of the ductwork layout, or can anyone show me a crude diagram? Is there a way to put a duct in the hall?

I was told by a dealer that my unit wasn't in the Dometic recall, although the serial number says it is. I only have two small returns, and was thinking about adding a bigger one in the center below the unit. With only two air returns, air flow is dismal. Not much airflow difference with both ducted units running,

Sorry for including the pictures in my reply, I didn't know how to delete them.

[brad2388]

If you can imagine a race track where the duct works run up both sides of your unit. Either in the front or the rear there is the turn 1 and 2 to complete the racetrack.

The back will be just taped off.


As far as the vent in the center you can add that to yours. I didnt add it to my new alpine because i added a third to it also.

You can get the vents at dwinc.com

[csterl01]

Thanks, based on the taped ends at the vent where I want to install a 3rd unit, I assume the crossover must be at the other end in the bedroom. One end of the duct goes past the skylight, the other comes up to it only. I might just have to dump that ac into the room by the window unless I can figure out how to extend the duct somehow. I ordered a 5 M borescope to check out what is happening in the ducts obstructing airflow. Since the main unit drops in from the top with no grill, etc. Inside, I am wondering if I have a leak between the supply and return sides. That might explain why the unit doesn't freeze up with the long run times. Any idea how to locate exactly where to cut in the center supply vent?

[csterl01]

How hard is it to take the ceiling down? And I am having a really hard time figuring to locate the temp sensor for the third unit. Interior walls in the living area are scarce

[brad2388]

Originally Posted by csterl01

Thanks, based on the taped ends at the vent where I want to install a 3rd unit, I assume the crossover must be at the other end in the bedroom. One end of the duct goes past the skylight, the other comes up to it only. I might just have to dump that ac into the room by the window unless I can figure out how to extend the duct somehow. I ordered a 5 M borescope to check out what is happening in the ducts obstructing airflow. Since the main unit drops in from the top with no grill, etc. Inside, I am wondering if I have a leak between the supply and return sides. That might explain why the unit doesn't freeze up with the long run times. Any idea how to locate exactly where to cut in the center supply vent?

Do you have a vent out the roof? The ac units drop right into the holes there.

[csterl01]

Originally Posted by brad2388

Do you have a vent out the roof? The ac units drop right into the holes there.

Yes, I have a skylight where I can install the third AC unit. I'm trying to identify a location to install a return directly under the current unit, which doesn't have any opening through the ceiling. I am concerned that the two offset returns restrict the return air as the openings are about 5/8" by 8" at best. I get very little airflow out the current (7) vents, with the one closest to the unit itself putting out no air at all.

[csterl01]

Can I add a quick return intake to my Dometic ducted unit which does not protrude through the ceiling? Third AC or not, I'm not getting much airfow from it, and adding the return and quick cool would have to get more out of what I have now.


I have 9 outlets on my system now, five going forward to my BH, bath and MBR, If I stuff a rag into the first duct on that run, I see no improvement in airflow in the four ducts in my LR. What gives? Also, I pulled one of my lights out of the ceiling and get cold air blowing out of the hole. Obviously have leaking ductwork, any idea how to fix it without tearing the ceiling out? I am sure adding the additional 350 +/- CFM will go a long way in overcoming the leaks, etc, but I would also like to get the most out of what I paid for.

[csterl01]

After following this thread, I decided to make what I had better before resorting to adding a third AC unit on my 2016 Sierra 371REBH. It appeared that there the return air was restricted due to too small and damaged return ductwork. I have added a return with quick cool to the main unit in the living area. Since there wasn't anything exposed in the ceiling, it wasn't an easy mod. Total time to add the return was about 6 hours, which consisted of removing the unit from the roof to locate the corners of the opening and fabricating extensions to fill the gaps between the ducts and the return. AIrflow has more than doubled through the ductwork, and the cabin cooled down to 75 deg within a couple hours on a 95 deg day with only the main unit runnng. I'm not looking to hang meat in the camper, but do expect to stay in the low to mid 70's on a 100 deg day. I'll update how successful I was after my trip next weekend. Total cost of this project was less than $60.



I have a much better understanding on how the unit and ductwork ties together after this project, and can document the entire project with pictures if anyone would be interested.


BTW: Thanks brad2388 for the excellent thread on how to add a 3rd AC to a camper. If my mods don't give me the results I want, I will be adding a 3rd unit to mine over the winter.

[brad2388]

Originally Posted by csterl01

After following this thread, I decided to make what I had better before resorting to adding a third AC unit on my 2016 Sierra 371REBH. It appeared that there the return air was restricted due to too small and damaged return ductwork. I have added a return with quick cool to the main unit in the living area. Since there wasn't anything exposed in the ceiling, it wasn't an easy mod. Total time to add the return was about 6 hours, which consisted of removing the unit from the roof to locate the corners of the opening and fabricating extensions to fill the gaps between the ducts and the return. AIrflow has more than doubled through the ductwork, and the cabin cooled down to 75 deg within a couple hours on a 95 deg day with only the main unit runnng. I'm not looking to hang meat in the camper, but do expect to stay in the low to mid 70's on a 100 deg day. I'll update how successful I was after my trip next weekend. Total cost of this project was less than $60.



I have a much better understanding on how the unit and ductwork ties together after this project, and can document the entire project with pictures if anyone would be interested.


BTW: Thanks brad2388 for the excellent thread on how to add a 3rd AC to a camper. If my mods don't give me the results I want, I will be adding a 3rd unit to mine over the winter.

Thanks!

Im sure that would help out alot of people even if they dont want to add a 3rd ac!

[BrendaM68]

Glad we found this thread - we're looking to buy a 2019 Forest River RV Sandpiper 389RD from Country Roads RV - so excited! It's prob better to make a new thread...