Roof Air Again!

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Kaputnick

Kaputnick

Active member
Joined
Jun 5, 2016
Posts
40
Location
Bakersfield, Ca.
    After servicing the basement air it will not keep up on hot days. I have been looking at an additional roof air in the current max air vent which is controlled by a switch next to the door. I have tried to find the switch and wiring for this vent with no luck.
    The questions I have are: will the current wiring support the load of a roof air? (Doubt it based on 12v but hopeful) If not, will it be possible to use the existing wires to pull new wires or are they fastened in the roof?
Thanx!
 
You might consider a Split Inverter type of Air Conditioner

Pioneer Inverter AC
https://www.amazon.com/dp/B01DVW6BG0/ref=asc_df_B01DVW6BG05036274/?tag=hyprod-20&creative=395009&creativeASIN=B01DVW6BG0&linkCode=df0&hvadid=167149293059&hvpos=1o1&hvnetw=g&hvrand=14142376611030567415&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9020774&hvtargid=pla-307589362235

The compressor unit can be mounted on the back of the motorhome. Cost is comparable to roof air and are a lot more efficient. Two can be run on a single 15 amp circuit. They are also very quiet. These are used extensively in Europe.
 
Kaputnick said:
    After servicing the basement air it will not keep up on hot days. I have been looking at an additional roof air in the current max air vent which is controlled by a switch next to the door. I have tried to find the switch and wiring for this vent with no luck.
    The questions I have are: will the current wiring support the load of a roof air? (Doubt it based on 12v but hopeful) If not, will it be possible to use the existing wires to pull new wires or are they fastened in the roof?
Thanx!
Click to expand...

Your vent fan will be powered by 12 Volt DC and the Air Conditioner will run off 110 Volt AC
 
Kaputnick said:
will the current wiring support the load of a roof air? (Doubt it based on 12v but hopeful)
Click to expand...
No.
If not, will it be possible to use the existing wires to pull new wires?
Click to expand...
Not likely.

New 120v wiring will have to come from the supply panel.  Some have done it on the surface. It can be finished to look decent.  I believe some have figured out how to punch through the styrofoam to the air ducts to run hidden or partially hidden wiring. It does depend to a large degree on the layout of your rig ... where you are putting the ac unit vs. where power has to come from.
 
Kaputnick said:
    After servicing the basement air it will not keep up on hot days. I have been looking at an additional roof air in the current max air vent which is controlled by a switch next to the door. I have tried to find the switch and wiring for this vent with no luck.
    The questions I have are: will the current wiring support the load of a roof air? (Doubt it based on 12v but hopeful) If not, will it be possible to use the existing wires to pull new wires or are they fastened in the roof?
Thanx!
Click to expand...

What did you have serviced on your basement AC unit?
 
John Hilley said:
You might consider a Split Inverter type of Air Conditioner
Click to expand...
I just had a 27 SEER inverter type split A/C installed in my small radio room/electronics lab. I am astounded how quiet both the inside and outside unit are, it's really quite amazing. However the physical characteristics would make for a difficult install in an RV. Install in a park model - you betcha.

Here's my write-up when I added a roof air to our Horizon. We've had to run the roof air lately beginning about 3 PM and shutting it off about 7 PM.
 
I am in the group that has this project on the "to do" list. Looking at the Coleman Mach 8 low profile. In my case, I can follow open cavities to the Washer/Dryer plug which is a dedicated 20AMP circuit. Since I do not have a Washer/Dryer and at this point no plans on putting one in, this will work fine. I have about 24 inches from where I plan to install to the "One Place" center that has the channel to run the cabling to the outlet. Probably be next year (2018) before I tackle this one. Read John's write up. Great information -
 
mickey53usa said:
I am in the group that has this project on the "to do" list. Looking at the Coleman Mach 8 low profile. In my case, I can follow open cavities to the Washer/Dryer plug which is a dedicated 20AMP circuit. Since I do not have a Washer/Dryer and at this point no plans on putting one in, this will work fine. I have about 24 inches from where I plan to install to the "One Place" center that has the channel to run the cabling to the outlet. Probably be next year (2018) before I tackle this one. Read John's write up. Great information -
Click to expand...
I have 3 Mach 8 ACs and hate them.  Reliable but man are they noisy, especially sitting on a fiberglass roof.  I was much happier with full size AC.
 
I see lots of complaints about the noisiness of the new Mach 8. Hard to believe that RVP/Coleman introduced a new top-end model that is actually worse than its predecessors. Maybe the motivation for the new model was a manufacturing cost reduction rather than improved performance?

Air conditioners in general have continuously improved in efficiency, with reduced noise and power consumption, yet RV roof a/c units seem to stay mired in mediocrity for the past 15+ years. Neither the a/c vendors nor the RV makers are motivated to invest in an improved product except perhaps to reduce their costs.
 
After having my basement AC pulled out and repaired I would think that anyone that has basement AC should probably have it pulled out and gone through...most have been in place for a minimum of ~7 years and just cleaning it would more than likely result in better performance...if you can do it yourself you will save $$....JMHO (just my humble opinion) :)
 
I'm sure it wouldn't take much to design a split unit with a compressor and condenser to mount on the back of an RV. When I was in Italy a couple weeks ago, I saw thousands of split units on the apartment buildings.
 
They are so prevalent in Europe (and other countries) in many cases because the buildings are old and retrofitting for ducted HVAC would be expensive and/or impossible. Having said that, if I was building a new house, multiple split units would absolutely on the table. If you had a split unit fail, you would still have others to pick up the slack unlike a single point of failure with one large traditional unit.
 
When we designed & built our new office, we had split systems installed - 22 interior "cassettes" running off of three outdoor units. They are quiet and each office has its own thermostat - no more "its too cold, I am to hot." Looked at putting one in my house last year when we replaced the HVAC - the cost to retrofit from central to split was just more than the budget could stand.
 
Gary RV_Wizard said:
I see lots of complaints about the noisiness of the new Mach 8. Hard to believe that RVP/Coleman introduced a new top-end model that is actually worse than its predecessors. Maybe the motivation for the new model was a manufacturing cost reduction rather than improved performance?

Air conditioners in general have continuously improved in efficiency, with reduced noise and power consumption, yet RV roof a/c units seem to stay mired in mediocrity for the past 15+ years. Neither the a/c vendors nor the RV makers are motivated to invest in an improved product except perhaps to reduce their costs.
Click to expand...
I agree!
I'm not giving up yet.  As I read this, my front AC is running and it's relatively quiet.  The other two "rumble".  I don't know how else to describe it, but I think the compressor vibrates and the fiberglass roof exacerbates it.  Maybe the chassis is loose up there.  I've already checked to make sure the tubing isn't hitting anything.
 
I just replaced the 13.5 K BTU Coleman Mach roof air I added about five years ago with a Dometic Penguin II (13.5K BTU but a 15K is available) and it's a bit quieter than the CM. There is/was no rumbling with both, just the sound of air movement.
 
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