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Old 03-14-2017, 08:49 AM   #1
jtrevill
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Ac vents

With the help of some forum members I discovered that my ac vents aren't connected and taped as well as they should be in my Raptor. Currently in the process of taping up and hoping to get better cooling, as it was dismal at best when I tried it this week.

Still Considering a second ac in the bedroom. Anyone done it? As I look at the ducting in the bedroom it runs right up to the install location for the 2nc unit. Is the second ac unit supposed to hook into the existing ducting or act as a standalone unit?


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Old 03-14-2017, 09:23 AM   #2
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I just cleaned up my ducts when we were having Summer a few weeks ago. The one to the garage wasn't bad but the main one to the LR and BR was awful. Half of it was taped off and there was a big gap going into the ceiling. Spent some time on it and checked each vent. I had barely any airflow out of the BR vent before, I probably have 10X as much now. I also blocked off the duct right after the BR vent. Couldn't tell how much farther it went. Can't wait to try it out and see how much difference it will make. Still probably need a 2nd but it's a start.

You 2nd AC won't be connected to the ducting. It will be a stand alone unit just dropping air into the BR.
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Old 03-14-2017, 09:37 AM   #3
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Thanks - yes, I turned it on a few days ago and it was only about 80 outside, but it never cooled down and there was very little air flow out of the ducts. I actually had some freezing up on the fins up inside the unit too. Now that I see what is happening, I suspect it was pulling a bunch of the cold air right back up inside into the fins.

Most of my ducts are connected, but just not very well and probably leak a little. My biggest leaks are right at the main unit, but I'm going to add to all of the ducts since I'm up there.

Too bad about it not adding to the existing ducting - they should have thought that out better - my ducting runs right up next to the install point!

How did you go about closing off the ends? Mine extend an unknown length beyond the last ceiling vents as well.
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Old 03-14-2017, 09:42 AM   #4
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canesfan; I sent the OP a link to your previous post on this same topic which included your pictures.
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Old 03-14-2017, 09:45 AM   #5
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yes - thank you. My vents were not near as bad as that! Mine were more coming loose from the ceiling than anything and allowing air to pass through to nowhere. It's like having my kids controlling all of the doors and windows on the house with the air on!
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Old 03-14-2017, 09:47 AM   #6
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You're welcome. I forgot, check the vertical divider up there, too. Make sure it's where it should be and not crooked and no gaps to allow air from one side to the other.

I blocked it off with some foam I had saved that was packing material from something (I ALWAYS knew it would be useful one day ). It's a grey flexible celluar type foam about an inch thick and it was the exact right height, all I had to do was trim it to length and stick it up there. Friction fit, too.

I also blocked off the garage duct after the second vent. Although I never had a problem with the garage getting cold. I keep the coolers back there to save on ice.

Edit - thanks Paraptor for supplying the link. I forgot about that and was looking for my pictures.
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Old 03-14-2017, 10:22 AM   #7
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Talking

canesfan; I am not saying that you cannot find Lickum Stickum inspection shops in PA , but believe me it will not happen with this state inspector, who is signing that sticker. Good to hear there are still a few around.

Your story reminds me of a situation after college, many ,many years ago, I moved to Ohio. After many years going through Pa inspections (normal plus Emissions) I had to register the vehicle in Ohio, which required a Ohio inspection. Pulled up in front of this designated inspection station and I go in to ask where to put the vehicle, pull into garage?? Attendant said its fine where it is.

Okay I am thinking they would drive test it first then move it into the garage and onto a lift. Nope, shortly after this attendant comes out with a pencil and tablet. Walks up to windshield copies down the Vin number and goes back in . Later he comes out and says OKAY you are ready to go. Cannot remember how much, if any, they charged.

Interesting concept, possibly paying no $$$$$$ to someone doing absolutely nothing.
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Old 03-14-2017, 10:26 AM   #8
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Originally Posted by jtrevill View Post
...
Too bad about it not adding to the existing ducting - they should have thought that out better - my ducting runs right up next to the install point!
Something to consider in connecting the second A/C to the existing ductwork is the size of the ducting. On most RV's, the ceiling ductwork is not "that big" and may not carry the volume of air necessary to distribute the output from two A/C units through the vents. That would be "wasting cold air"... Sort of like trying to fill a swimming pool with a 1/2" garden hose. Sure, it'll eventually get full, but using a 4" fire hose from the hydrant out front will fill it in an hour rather than 3 days.

It's the same with cold air from two A/C units "trying to push" the volume through a "too small duct".... You may find more BTU's of cold air are delivered to the coach interior by using a "stand alone" grill on the bedroom unit.
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Old 03-14-2017, 10:40 AM   #9
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Something to consider in connecting the second A/C to the existing ductwork is the size of the ducting. On most RV's, the ceiling ductwork is not "that big" and may not carry the volume of air necessary to distribute the output from two A/C units through the vents. That would be "wasting cold air"... Sort of like trying to fill a swimming pool with a 1/2" garden hose. Sure, it'll eventually get full, but using a 4" fire hose from the hydrant out front will fill it in an hour rather than 3 days.

It's the same with cold air from two A/C units "trying to push" the volume through a "too small duct".... You may find more BTU's of cold air are delivered to the coach interior by using a "stand alone" grill on the bedroom unit.
Our 2nd AC in the bedroom is not ducted into the rest of the ductwork off the main 15k unit. When we want to watch TV, and it's not blistering hot, we just turn on the bedroom AC and place a fan inside the bedroom to push the air into the living/kitchen area. It is a 13.5k unit and it works well unless, as I mentioned, it is just very warm outside.
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Old 03-14-2017, 11:25 AM   #10
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Ac vents

Here's the end result of correcting the air flow issues at the main unit. I also redid every vent, but didn't take any pictures. Did notice quite a bit of air flow increase (probably not 10x, but much better). I also suspect the unit pulling cold air back into the return was causing the freeze up on the fins. Hopefully this helps. I ended up using a thick piece of sticky foam to put on the divider. It too was askew. I straightened and taped it up as well.

Thanks for the thoughts on the 2nd unit - yes, I agree the ducts probably can't hold that amount of air flow. I will definitely be putting a second unit in before summer - we are frequently in 100+ temps (even though I hate it) and would hate to cook. Looks like I'll just shut off the bedroom and bathroom vents and allow the 2nd unit to cool those areas and the main unit can focus on the living and garage. After just about 30 minutes today, I too have a much cooler garage than elsewhere! Its funny because when running the heat - the garage is actually the cold area too and it gets limited heat.

Anyhow - thanks again for all of the help. I have my next project planned and will "bother" everyone again for their thoughts in a new thread later today probably LOL
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Old 03-14-2017, 12:42 PM   #11
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Cool

I like you, also considered a second AC for the bedroom which in our Raptors is prewired. After investigating I found out that the prewired area was intended for a non-Ducted AC, local vents and thermostat. I just could not see investing that kind of money into a unit just for the bedroom, in my eyes an overkill for that area as well as not helping the rest of the Raptor

Since then it has been bugging me why vents, especially the one in the bedroom had almost no air flow. After reviewing the main AC unit and all the output registers, I found them poorly taped and as a result significant conditioned air was being lost into the attic. After basically tapering (AL Duct tape, recommend around 3” wide) all duct interfaces the main unit and registers, there was a significant increase in air flow out of the registers as compared to before tapping.

I never really had significant cooling issues but had to open and close different output registers to meet the needs. Now again other than longer trips a few times into central southern states, we are mainly in the northern states.

Now here is the only thing I would consider doing, if I had nothing to do , get a ducted unit and modify it accordingly to mount in that prewired area. That current output register, which is inches from the prewired area, I would tap the new unit into the duct at that point. I would add a second output register in that same duct near the sliding closet doors. This is the duct that canesfan has blocked off at the referenced register. Then I would block off the duct after the register in the bathroom heading toward the main unit. Would try to also tap off the duct at this point to a new register added just above the steps, maybe somehow with flex duct ?? Run a thermostat wire from the new unit to the hallway and look into converting to a single dual zone unit.

Okay, so far we now have a new ducted unit installed into the prewired area, ducted into the existing bedroom duct feeding two registers in the bedroom (one existing and one new), one in the bathroom and possibly the one added at the top of the steps.

Now for the existing original AC unit in living area, block off existing duct just after the register in front of the entertainment center, Duct heading toward bathroom. So now we have the original AC unit still feeding the two original ducts feeding all output registers in the living area and the garage.

Would take a little work but that is the only way I would buy a second AC to install it in the prewired area in the bedroom. Just read this again, checked my age, well may never happen. New rig at my age , do not think so.

Seriously could be fun, hardest thing I think would be designing a plenum from that new unit into the existing adjacent duct as well as tapping into the bathroom register area for that proposed register above the steps. If ever completed would have one unit controlling the upstairs (hall, Bathroom, bedroom) and the original for the downstairs ( living area and garage)

Just thinking about this effort is making me tired . Now that I am not cooling the attic, I think all may be fine
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Old 03-14-2017, 01:52 PM   #12
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I like it!! I have to see how close the ducted unit would come to the existing ducting.... maybe very feasible! I need someone to step up and try it and give me some step by step instructions [emoji23]. Otherwise if I try I'll let you know how it goes lol.


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Old 03-14-2017, 03:10 PM   #13
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My guess is say 9", duct runs parallel with rewired area. BUT as you recall when adding the tape that duct opening was offset from the edge of the AC Unit. I purposely picked that vent because you already had an access hole at that register to the duct and the opening where the new unit would go. The further the duct is toward our sliding door closet the more challenging working with the two will be, That is why in that last post if you could build a metal plenum with a turn getting it near that register hole for connection to the duct. Do not think you you to be playing with opening up than ceiling??

Then again that is my concept, when we get to the design stage actual dimensions of that AC unit will be needed then some drawings, Again goal was to hit existing duct near that existing register opening
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Old 03-20-2017, 05:59 AM   #14
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Just got home from my weekend out - and while taping the ducting helped increase airflow, it still does not cool near enough. I'm probably going to have to take it in, as it was only in the 60-70's and never cooled the trailer off. I want to see an improvement in the existing system before I go throwing another unit at it.
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Old 03-20-2017, 06:29 AM   #15
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Paraptor, I have folding doors.

I like your idea. When can you come down and do mine?

jtrevill If you have issues keeping your rig cool when it's 60-70 outside you have some serious issues going on. It hasn't warmed up enough for me to try mine after the refurb. I'm not expecting an earth shattering improvement but I'm hoping for a little bit better. The trailer is just too big for the single 15K AC, and since cool air sinks, what air does make it to the bedroom goes back down the steps to the living area. I know my AC works, because when I keep the door to the garage closed it will be 10-20 degrees (very rough guesstimate) colder in the garage than up front. So I guess one solution is to close the garage vents trying to force more air up front. Not sure that would accomplish much if anything. So my solution to date has been to keep the garage door closed and keep it cold in there, keeping the coolers in there saves on ice.

To note, the reason I didn't get the second AC in the first place was my thought process was "I don't camp in the Summer and I seldom use the AC, so I'll try it with one and see". Then all of a sudden I started camping in the Summer. Should have got a bigger truck, too.

Paraptor, I don't really have folding doors. Sounds like your bedroom setup is completely different than mine. I have a dresser in the middle and a 'wardrobe' on each side.
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Old 03-20-2017, 06:44 AM   #16
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Yeah I definitely have an issue. It should be freezing cold at these temperatures. And its barely comfortable. The air feels cool coming out but I haven't put a thermometer in it. It's got an extended warranty, so i'll just go through that.

However, my garage does get colder than the rest of the trailer too! My plan is that once i get this figured out, I'll still add the bedroom unit and use it to cool the bedroom and bathroom. And then close the vents and allow the main unit to cool the living and garage.

I think that Paraptor should come do both of ours at the same time (more efficient that way). But yes, I think I have a significantly different bedroom layout than you guys too - I don't have sliding closet doors.
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Old 03-20-2017, 07:40 AM   #17
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Canesfan, Jtrevill , Good Morning,

Just read your recent posts, with all recent references to "Fake ......" in order that we provide the most accurate information I suggest both of you examine the labeling on your rig. Specifically my reference is to possible Raptor Identification FAKE Labeling" Is it really a Raptor.

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Old 03-20-2017, 07:46 AM   #18
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canesfan --

I think he's just misdirecting now away from our posts suggesting he perform the ducting upgrades to our rigs!
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Old 03-20-2017, 07:58 AM   #19
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Something to keep in mind if you are seriously thinking of adding another A/C unit into existing ductwork, is the duct size itself. It's probably not large enough to support the amount of airflow generated by two units. And even if it was, if two A/C units are running at the same time, from opposite ends of the ductwork , they are effectively trying to push air against each other. Of course, some of the air will be coming out of the registers, but probably not enough to give you good airflow across the evaporator coil of each unit. Low airflow across the evaporator(s) will result in them freezing up because there is not enough of a heat load to boil off the refrigerant circulating through the evaporator.
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Old 03-20-2017, 08:12 AM   #20
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Paraptor - I'm not understanding your last post. Are you getting into the "adult beverages" already?

jtrevill - I think yo may be right. Wait...look over there...

xrated - Most of the recent discussion is more "tongue in cheek" than reality. However, if it were to be done, if you read back through, the main ducting would be broken into two "sections", blocked off or not connected to each other, making a "front" duct and a "rear" duct, one for each AC. You are right, it would not work well to have them both connected to the same duct trying to blow air at each other, as well as the volumes not being adequate. However, I don't really see this as becoming "reality".
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