Community Forums

Capt Steve · 03-14-2021, 09:11 PM

You need tp keep in mind that 20 degrees is about all you can realistically expect out of just about any RV AC. If it is 100 outside and your AC gets the interior of the coach down to 80 that is probably about as good as it will ever get. Parking in shade, insulation on windows and vents certainly helps but keep it real... if you get 20 degrees down from the outdoor temperature you are done.

Ron Dittmer · 03-14-2021, 10:38 PM

Frank,

Just adding my 2 cents into the pool.

I agree that most RV roof-top a/c units will last a very long time, much much longer than 6 years.

It sounds like your rig needs two a/c units which is actually commonly found on higher-end class-C rigs in the 26-32 foot range.

There is one thing you can do yourself. Get on your roof and take off the a/c cover, and inspect the radiator-looking thing. If there is an accumulation of debris on it, then clean it off with a new paint brush and vacuum cleaner. If the paint brush is too gentile, cut the bristles shorter to make it stiffer for a more aggressive brushing.

Compressed air also works, but not everyone has access to that. If you do, don't blow the dirt into and through the radiator, blow it "off" from the back side.

Also, be careful not to bend those fins. If you do, straighten them out using a brand new all-bristle toothbrush. Melt the handle of the toothbrush on your stove to bend it nicely for the job. Let cool and you are well equipped.

At home, I have lots of toothbrushes bent at various angles for various detail work.

Avenger61 · 03-16-2021, 08:29 PM

My a/c is ducted throughout the mh. When I cleaned the ductwork I simply removed all the ceiling vent covers and the a/c cover and used a leaf blower to blow everything out of the ductwork. I couldn’t believe how much debris, dust and duct material left from the manufacturer I blew out. It certainly made a difference in air flow through the ductwork.

Bobby F · 03-16-2021, 09:06 PM

Six years!?

My 1993 rooftop is original, and works great.

If I parked it on the southern US border and ran A/C daily for six months every year, I expect it would be worn out by now. But with "normal" use, no, it should have a much longer life than six years.

(At 100 degrees and above, it's laboring, and I always wish it would get cooler inside. But for what it is, I've learned to be realistic. Most C's aren't insulated enough to get cold in such weather.)

Wmjp · 03-17-2021, 03:16 AM

Quote:

Originally Posted by frank1018

This unit is a 13.5 . I have a side window but no front window over cab. It does have that cheap vent over cab. Bedroom is the farthest. It has 3 windows. After reading some advice I will definitely add some reflective on the windows back there. It may help. Those who have said they cleaned the ductwork, are you talking in the cabin area and what did you use? Thanks guys.

Make sure you check the airflow within the unit. The ductwork inside is sketchy at best. Insure that there’s no cross flow between the intake and exhaust openings. My a/c just died. Original unit on 2011jamboree. Check out anything else that you can get to because your not dealing with the highest level of construction/ assembly.

Ron Dittmer · 03-17-2021, 08:17 AM

As others have stated, when it comes of RVs of all types, they generally have inadequate thermal properties given the way they are constructed. How effective the a/c unit and furnace are depends on a few obvious factors.

- The size of the a/c unit given the volume of air to cool. For class C's, some have high ceilings, wide bodies, over-head bunks, and multiple slide-outs. Other rigs like our rig SEEN HERE has a low ceiling, narrow body, an insulated B+ cap, is only 23'-8" long, and has no slide outs, so cooling and heating is much more effective.

- A slide out is not as energy efficient as a typical wall. More than just the extra volume of air to cool, the moving box and gaskets have reduced thermal characteristics. Having two or three slide outs compounds the inefficiency.

- Regular glass versus thermal glass. Thermal pane glass is surely better. We have thermal glass. It is much better compared to our previous motor home that had single pane glass.

- The color of the motor home makes a big difference. Pure white is surely ideal when dealing with heat. Our rig is silver/gray with a white roof. The painted sides are not as cool as white but fortunately is only just warm to the touch. Lately, some rigs are being painted darker colors which is going to absorb more heat from the sun.

As optimal as our rig is with regards to heating and cooling, the area of the van is the same as everyone else. When dealing with heat, you want to block the sun "outside" the windshield to avoid heat from building up inside the van. There are very few expensive products that do this well. I use cheap pop-open sun shades that Walmart sells for vans. As long as it is not windy, I set them on the glass and let the wiper blades hold them in place. Any significant breeze, and it's a loosing battle, forcing me to block the sun on the inside which is surely less effective.

Phil G. · 03-17-2021, 04:55 PM

The link below is the type of windshield cover to use on a Class C's cab windshield - it goes on the outside of the windshield and is held in place by magnets and the windshield wipers. It's heavy material and blocks all sunlight.

It's also good in cold weather to better insulate the cab in cold outside air conditions so as to reduce the effect of a chilled cab's air cooling the coach interior - even though you might have a curtain between the cab and coach areas.

The one we use on our Class C is over 13-14 years old and is still in great shape, with no rips or tears. It comes in a nice heavy duty storage bag so you can just stuff it into an exterior storage cabinet when not being used:
https://www.campingworld.com/overdri...Fwindow-covers

By the way, it goes without saying that in hot weather as many areas of the coach as possible that aren't needed during specific times should be blocked off with a curtain - such as the cab and bedroom areas, for example. The less interior volume that needs to be cooled the better, with respect to the capacity of the coach's air conditioner.

chs · 03-17-2021, 05:59 PM

Quote:

Originally Posted by Phil G.

The link below is the type of windshield cover to use on a Class C's cab windshield - it goes on the outside of the windshield and is held in place by magnets and the windshield wipers. It's heavy material and blocks all sunlight.

It's also good in cold weather to better insulate the cab in cold outside air conditions so as to reduce the effect of a chilled cab's air cooling the coach interior - even though you might have a curtain between the cab and coach areas.

The one we use on our Class C is over 13-14 years old and is still in great shape, with no rips or tears. It comes in a nice heavy duty storage bag so you can just stuff it into an exterior storage cabinet when not being used:
https://www.campingworld.com/overdri...Fwindow-covers

By the way, it goes without saying that in hot weather as many areas of the coach as possible that aren't needed during specific times should be blocked off with a curtain - such as the cab and bedroom areas, for example. The less interior volume that needs to be cooled the better, with respect to the capacity of the coach's air conditioner.

Same one I have. Works great just make sure it's put away dry. Very suseptable to mold if put away wet.
I try to take it off the afternoon the day before we leave a site so it's really dry.
If it does get mold, use a bleach and water concentration to clean it. Not too often or the thread will rot from the bleach.

chs · 03-17-2021, 06:07 PM

One thing I learned. Especially in cold weather. Be sure to put chassis AC in the max position, then turn off before you turn the engine off. Otherwise the vents will stay open and the cold air get drawn into the rv. In the hot weather, when you turn ac on it will suck the outside hot air in also.

Phil G. · 03-17-2021, 08:56 PM

Quote:

Originally Posted by chs

One thing I learned. Especially in cold weather. Be sure to put chassis AC in the max position, then turn off before you turn the engine off. Otherwise the vents will stay open and the cold air get drawn into the rv. In the hot weather, when you turn ac on it will suck the outside hot air in also.

Excellent recommendation above! We've been doing this for years in our Class C motorhome.

In the Ford E350/E450 chassis I believe that the vents also are closed when you turn the dash vent control to it's OFF position before turning the engine off.

Also, we always set this control to the A/C Max position in warm weather when traveling on dusty roads so as to keep the interior cleaner - while at the same time staying cool.

RV2009 · 03-19-2021, 12:19 PM

Quote:

Originally Posted by frank1018

What kind of life expectancy can you expect out of these units? My unit is 6 years old. I purchased used. 30 foot with one unit. Does not seem to cool all the way to the back bedroom that well. Just wondering how often one has to replace these.

Don't know what the life expectancy is. Ours is still the original one from 2001, and blows ice cold.

Had to replace something a few years ago, don't remember what it was, but that is all that ever went wrong with it.

Of course we clean ours once every year and keep it maintained.

Happy Camping!

frank1018 · 03-20-2021, 08:01 AM

Well service called and should be ready by the end of next week. I hope cleaning will help. I also saw a few things on you tube about the ducts I will check. Seems air can leak in a few areas and make it less efficient. I have some work to do in checking for poor workmanship with ducting.

Josephls · 03-20-2021, 09:13 AM

30 foot rig needs 2 ac units if you travel in the summer. Ours is 28’ and one is not enough when the temps are in the mid 90’s and up. Which is a majority of the country in the summer.
A new ac won’t make any difference . I installed a new unit to get one that’s quiet and the newer units don’t cool anymore than older units which is to be expected.

I’ll never own another rig of this size without 50 amp and 2 ac units. For me this was Lesson learned.

NYBobbo · 03-20-2021, 09:32 AM

my Mach 5 died in 5 years :( replaced it this past summer. The dealer had a stack of dead units sitting out back. Mine sprung a leak somewhere and the coolant leaked out. Apparently they do go bad and trying to find someone to find the leak and do the plumbing to refill isn't worth doing.

Like everything else on RVs if you use them they seem to wear out, and if you don't use them they tend to wear from not being used. Seems you can worry about things failing or just use your rig and deal with the issues as they come up.

Just replaced my propane sensor.... right on the cover it says it's good for 60 months. They were right, possibly an internal timer went off.