brinasmemaw
southern Oklahoma
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I just finished installing a second AC in our 2005 Holiday Rambler Alumascape fifth wheel. I installed it where the thermostatically controlled Fantastic Fan was in the living area. The install was fairly straight forward other than trying to fish the thermostat wires across the roof & down the wall. I never did get the wire down the wall so ended up having to hide the wire behind that wire cover stuff that is on the wall (name escapes me right now). When I turned the ac on it works great, blows really cold air & works as it should EXCEPT there is no air coming through the ducts. I initially thought there was likely a block at the end of the duct where the original ac ended but that wasn't the case. I am at a loss now as to where/how to hook the ducts into the second unit or what I might have done incorrectly. Has anyone else had this problem & if so how did you find/fix the problem? You help is always appreciated. Mac
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Mac & Becky
Seeing North America one mile at a time
2006 42' Allegro Bus towing a 2011 Cadillac SRX
2011 F350 6.7L Crew Cab FX4 & 2005 Holiday Rambler Alumascape for Alaska trips
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hershey
Albuquerque,(fulltime) NM, USA
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Can you look into the ducts with a mirror?
hershey - albuquerque, nm
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fla-gypsy
North Florida
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So how do you know it blows cold air if nothing is coming through the ducts?
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Old-Biscuit
Across the USA
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This second A/C has a discharge plenum that you connected the existing ducts to....correct?
No ducts connected then air will just blow out the grill openings on A/C.
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dougrainer
Carrolton, Texas
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1. There are NEVER any connections to the roof AC ducts from a Roof Vent. You have to make and install and cut out the ducting to tap into the existing ductwork
2. IF you have cold air coming out, then you used the standard lower duct kit(not for ceiling ducting) and NOT the Roof Ducting kit. So, to tap into your roof ducting you will have to buy the correct ceiling ducting kit
3. IF you did use the Roof ducting kit, you need to design and make a discharge plenum from the new AC kit to your roof ducting.
4. Not so straight forward is it Doug
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Road Runners
Tampa Bay, Florida
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I am not sure how you hooked up your AC. Is the hole where the fantastic fan used to be now the return air plenum for the new AC? And, then how did you hook up the cold air outlet of your new AC unit? I assume, from what you wrote, that you hooked the cold air outlet of the new AC into the present AC ducting? It's all sort of confusing.
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jimmyfred
Tx
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..............The origional A\C unit is the only one that should be pumping air into the duct system ! As others have pointed out ALL air from 2nd. A\C is ejected from a surface ceiling register ! IF , you have somehow hooked the 2nd. A\C outflow air into the existing duct system , (1)you have overloaded the system because if was designed for the CFM volume of ONE A\C unit. Posible that the metal partition separating the cold air outflow from the return air is NOT working thereby allowing a circular flow which allows cold air too be pulled directly , Back INTO the return air and so NO cold air is being directed INTO the interior of the trailer . , jf
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Pirate
Appalachia
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dougrainer wrote:1. There are NEVER any connections to the roof AC ducts from a Roof Vent. You have to make and install and cut out the ducting to tap into the existing ductwork
2. IF you have cold air coming out, then you used the standard lower duct kit(not for ceiling ducting) and NOT the Roof Ducting kit. So, to tap into your roof ducting you will have to buy the correct ceiling ducting kit
3. IF you did use the Roof ducting kit, you need to design and make a discharge plenum from the new AC kit to your roof ducting.
4. Not so straight forward is it Doug Doug, over the past few (several) months I have noticed that you take the time to provide some real good answers to issues. I appreciate reading your replies, please continue to share your knowledge.
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brinasmemaw
southern Oklahoma
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I appreciate all of the replies guys. I made sure that there was factory ducts in place for the 2nd ac, or at least is says in the brochure that it is wired & ducted. @hershey, I am not sure if I could ever get a mirror up there since it is a rather small hole but I might give it a try just to see whats there. @fla-gypsy their is plenty of COLD air coming out around the speakers that are in the ceiling & around the unit itself. @roadrunners, yes the plentum/return air is covered with a grid type panel to allow return flow in the square where the fan was. @jimmyfred, I don't believe that the second ac should only blow from the ceiling register to be true due to the information I found in the original brochure regarding the ducts being in place from the factory. @ dougrainer, I follow your line of thought on this but for the brochure to say it is ducted from the factory for a second air unit I am not sure what that means. I used my fish tape to run the length of the vent thinking maybe there was some block but the tape ended at 16' & I didn't find anything blocking the duct. I am going to attempt to find someone at the number Holiday Rambler lists that can tell me more about what is needed to duct the ac. Doug as I said I think you are correct but I don't want to start cutting holes until I know for sure where to cut them. And no Doug, it isn't so straight forward at this point. Thanks again to everyone for taking the time to reply. Mac
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bearwayne
Pensacola, FL
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brinasmemaw said "their is plenty of COLD air coming out around the speakers that are in the ceiling & around the unit itself."
I think that's the key to what's happening. The air is not flowing into the duct work but rather into the space between the roof and the ceiling. I had a similar problem when my AC unit was replaced after an unfortunate encounter with a tree. I couldn't figure out why the new unit didn't cool as well as the old one. It turned out that the new unit was blowing into both the duct work and the "attic" because the installers didn't close off the openings between the ceiling and the roof. Once I did that, performance improved considerably.
Maybe duct work is *supposed* to be installed where your vent fan used to be but that it wasn't *actually* installed.
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