Is it normal for my RV to be impossible to keep cool interior while driving?

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horsegirl

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We have been RV ers for a long time, but have never really traveled in this type of excessive heat. We are heading west from Nashville to California. Yesterday we were in Kansas and yes I know 106 is not normal. but ... we had the dash air on ( dont usually ) were running the generator with our basement air on , and had portable fans running for the dogs. It was 96 in the RV when we got there and our older dog was really having a hard time no matter what I did. Is it really just a fact that when you travel in the heat like that you cannot keep reasonably cool at all? We left at 7 this morning so we can stop mid day and hopefully avoid a repeat. It seems that since our coach is not cheap, despite being 8 years old, it would be better insulated that that!!!!! Since our basement air is insufficient to cool this coach, and until we can get to our destination and add roof air, we bought a stand up unit that vents out the window which is the only way we have survived at night etc. We have foil on the windows to prevent the sun and heat. Any similar experiences and or suggestions. At least tomorrow morning we head on in to Colorado to see son in the army and hopefully cooler there. Have a good day!
 
I think it's the basement AC that is killing you.  I've not heard good reports on those.  We have traveled in 100+ temperatures in our 40 foot DP, running the generator and both roof airs and it stays very cool.
 
There has to be something wrong with your basement air. I can see it not keeping inside freezing cold,but that is nuts!!You should be able to maintain at LEAST a 20 degree TD. Adding the roof air will make a huge difference, but get the basement air checked out, it may just need a little service and cleaning.
 
Several days ago we were driving through Indiana and the ambient air temperature was about 104.  I had to run the basement air, dash air, AND the roof air for the first time ever while on the road to keep the cabin cool.  For the last 75,000 miles of travel in our Horizon the dash air and basement air combo has worked great to keep comfortable while on the road.

Take a look at our website (RV section - link in my signature) for a list of all of the upgrades we've done to our Horizon, you should add a roof air unit like we did a couple of years ago.

One other thing you can do is to partially close the ceiling vents in the center of the coach - this will force more air to the forward two vents, but the permanent solution is the roof air.
 
John, do you think there is anything wrong with the basement air or just inadequate as we already know? Maybe we can find someone in Colorado Springs if necessary, although I am hopeful the worst of the heat will be behind us then. However, until we find a solution, do not want anymore trips in hot weather. 96 is way too much when you get to the campground and are trying to set up.
 
A quick test is to stick a thermometer (or non-contact IR thermometer) into the first ceiling duct in the bedroom, the temp should be about 20 degrees below outside air.  Check the rear of the basement air where the ducting attaches - make certain you don't have air leaking.  Feel the back of the rear cap for any cold spots - there is a molded "Y" where the single duct splits into two - there was a problem with the molding on some of the early "Ys" where they were cracking.
 
The a/c should be able to reduce the inside air temp about 20-28 degrees as it passes through the a/c system.  Measure the air temp at the inlet (air return ducts) and again at the outlets. The difference should be at least 20 degrees and more like 25-28. If your a/c can do that, it is working as designed (which does not necessarily mean the whole system is adequate for your coach).

Few RVs are sufficiently insulated to keep it much more than 20-24 degrees below outside ambient temperature in the daytime. They gain heat as fast as the a/c system can cool it, so its a continual struggle.  Sun-loading is the major problem, so an RV in the shade or in the evening, when direct sun is less of a problem, will often cool much better.  You can help with reflective foils in the windows, insulating pillows in the skylights, and awnings to keep the sun off the sidewalls as much as possible. Too bad we can't fly awnings while driving down the highway!  Increasing the cooling capacity with an additional a/c is the most help - you chill the air faster and stay ahead of the loss rate.

It sounds to me as though your a/c system has a problem beyond the usual complaints. Either it is not cooling the air that passes through as it should, or there is a leak in the ducting that allows super-hot outside air to mix with the chilled air, or the ducting itself is simply losing too much chill. Unlike roof air, your ducting is exposed to outside air as it makes the trip from the basement compressor to the ceiling air distribution.  You may be able to help it by adding insulation to the main duct (which probably runs up behind the rear cap).
 
Sorry to sound so pedantic - it's a failing of mine! Was just trying to make the point that  the measure of the a/c's proper functioning is a different thing than how cool the whole system gets. The two numbers (both 20's) are so similar that it gets confusing.
 
I would also look for some kind of hole around the dashboard letting hot outside air in making the dash a/c useless. I say this as my 2006 Voyage Ford cools so well that when traveling threw Birmingham Al it was 104 & I did not have the generator or basement air running & it was OK in the front. Not Cold but OK. Hot in the back of the rig. Just a suggestion but look foroutside air getting in up front. Art
 
Like most said, our 3 A/C roof units can keep the inside temps approx 25 Degrees cooler than the outside air (gen running) while driving.... (no prob when on shore power/stopped)
While we were in 105 - up to 112 temps, I ran the dash air which brings it down fine even then....
BUT..  that added  load on the motor raised the engine temp another 5-10 degrees...normally runs 175 while at 60-62 mph - when over 100 outside, runs around 185 . . so a couple of times when the engine temp went to 200 in the hills, I shut off the dash air and ran warmer inside until through them.....
 
I think everyone is right about a possible leak in the vent system, and here is one way to check.  The back cap is where the ducting is that runs from the AC unit to the roof, and then throughout the coach. If there is a leak, the vertical portion in the rear cap is a good bet.  Check around the elbow that comes out of the AC unit and see if you feel a cool draft. If so, repair with foil AC tape available at Home Depot or the like. 

Second, use a coat hanger with a piece of toilet paper taped to the end, and while the AC is running, slowly move it around the ducting in the rear cap while laying on your back. A flashlight may help to see.  If the TP blows around at all, there is a leak in the ducting.  From what you describe, a duct leak is really possible.  Also open up the panel on the outside of the coach and by removing the front panel of the AC, you may also discover a leak. 

Good luck and let us know what you find.
 
This thread got me wondering if our basement air was working okay,  I've had to tape up the joint where the vertical duct run meets the elbow coming out of the unit previously.  When I checked ours this morning, we had air pouring out of the joint  ::).  Simple Green to clean the dirt around the joint, lacquer thinner to degrease it then lots of duct tape.  Wow, what a huge difference in cooling.  I had 38* air coming out of a ceiling vent!

That's a great tip Marty about the tissue on the coat hanger - hadn't thought about that one.

A couple of other tips for horsegirl -

To get maximum cooling performance, both compressors must be in operation - fan on high (I think that's a requirement for both compressors to run) and turn the thermostat way down - ten degrees or so under your desired room temp.  To verify both compressors are running, plug into 30 amp power (or run the genny) and shut off the fridge (or put it on LP) and water heater, turn off the battery charger.  If both compressors are running, you should see a current draw of at least 21 amps - anywhere from 21-25 amps would be normal.

The AC filter should be one of the cheap ones that aren't very dense - you need maximum air flow so don't use one of those high-dollar hypo-allergenic types, they will restrict the air flow too much (I think that was your tip Marty if I recall correctly.)
 
I've experience extremely hot drives like the OP posted, with our 2 roof A/C units.  Part of the problem was excessive coming through our doghouse cover (the interior "hood" that allows you engine access between the front seats).  I insulated that cover and it made a difference, but it's not airtight and hot air still makes it through.  This wouldn't be an issue of you have a rear-engine motorhome.  But you can still pick up a lot of heat via sunlight, through the large windshield, skylights, and any large side windows you might have (I have all 3 of those features in my '94, see my signature photo link).

Our dash air doesn't work, and even if I did recharge it there are only 3 skinny vents across the dashboard that I don't think would make much difference anyway.

What we do to ride comfortably is PRE-COOL the interior as much as possible.  I will start the generator and run both A/C's for 1-2 hours in the cooler morning hours before we leave.  Once that heat accumulates inside the rig while driving, there's no way that the A/C will defeat it and cool it down until long after the sunlight and engine heat has subsided.
 
Jim and Linda - We're currently in Colorado Springs (where it's sunny and 90-ish) waiting for a service appointment for our basement air.

We worked with Turbo's Mobile RV Repair (in Monument, but Eric will travel to the Springs), which was highly recommended by RVP. Eric made the diagnosis (refrigerant leak that occurred 16 days after we had AC repairs made in Forest City). Turbo's doesn't do refrigerant work (many shops don't), so we scheduled an appointment with DM RV Repair in Loveland. (Also recommended by RVP - we've talked to them lots!) We'll be there Monday!

We've learned a lot about our basement air over the last year. (Maybe when it's all done we'll post about our trials and tribulations.) But, the one thing we know is that when this unit is working properly, it cools our coach just fine. (For example, 95 degrees in full sun and 77 degrees inside.) If it doesn't, something is wrong.

Good luck!
Mary and Paul

 
Another thing to consider is the outside color of the RV.  The darker the color the more heat that is absorbed from the sun.  Our budget Fleetwood Fiesta is all white.  Our single rooftop AC will keep the interior about 80* even though the outside temperature is in the high 90s.
 
This might not have anything to do with you present problem, but it is a problem we once encountered. We had an allergo bus when they still had a gas engine. They had very cheap front air ducts. We had several hot days and every where the air ducts crossed over a brace the ducts collapsed over the brace. I went to an auto repair shop and got some heavier ducts and replaced all the duct works. 100% improvement in the front air.

Frank
 
Marty  and John have just pointed out exactly what I found on our old Luxor. The rubber foam gaskets the sealed the basement AC to the duct work had deteriorated and when new was a mismatch on alignment. I realize our old girl has a lot more age on her but this could still be a problem for you. I also found leaks in the upper cabinets where the duct transitioned from vertical to horizontal into the ceiling. That cabinet was a nice place to keep things cool.

Replaced the original gaskets with Armaflex brand sheet insulation cut and glued to fit.
 
Well, did the temperature checks and found that it appears the basement air is working. There was a 24 degree difference between the air going in the intake and the air coming out of the vents. So, I am guessing that it is just a combination of the amount of heat the RV is absorbing and the fact it was over 100 degrees, and that the basement a/c is just not sufficient in size for our RV .  Of course, now that we are in Colorado to visit our son who is serving at Fort Carson, it is not quite as hot, 94, but it cools at night so at least we are starting the day cool and easier to keep it that way.
Another maybe dumb question,  sometimes I see water dripping out from the a/c and sometimes not. What determines that.
Thanks for comments and advice , cant wait to get to west coast. Since we will be living in RV full time, and fairly stationary, hope to be able to afford adding that roof a/c and  possibly residential refrigerator.
Must also say that in cooler weather, frig is working too.
As I said, given we all spend a lot of money on our rigs, seems like we should not be so affected by weather. I wonder how those full timers in Arizona do it.
 
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