Coach Too Hot

[bartman62]

I have a 2011 430qs motorhome, Charleston by Forest River, we have (2) 15,000-BTU Dometic Duo-therms that can't cool the coach when the o.a. is over 90*F.

Both units run on full power but can't make more than a 5*f. difference from o.a.

Is my only option to add another roof-top unit?

[tbutler]

There are a number of things you can do to reduce the load on your air conditioners and thus make them more effective.

1. If possible park the coach with the windshield facing north. This will minimize the amount of sunlight coming in the windshield and side cabin windows. (Of course the obvious answer would end here... Drive in the direction you are facing until dark. Repeat until the daytime temperature is below 90 degrees! )

2. Request a shady site to minimize the amount of sun affecting the remainder of the coach.

3. Use all your awnings whenever possible. The large awning may not be useful in high winds but the smaller awnings should be used anytime the air conditioners will be operating.

The above are all no-cost items that you can do to reduce the impact of the sun on your coach. Here are a few more no-cost items.

4. Cook outdoors or use the microwave when possible. Eat cool, no cook meals when possible.

5. Shower at the campground showers and hang all wet clothing and towels outdoors until dry.

6. Keep lights, TV's and other electronics off during the heat of the day.

7. When parking after a day of driving, open the engine cover to allow maximum ventilation to the engine compartment. Do the same for the generator if you have been using it while driving. You can close these after sunset or the next morning if you are in a secure area.

Now for a few items that will cost you money but will further reduce the heat load on your air conditioners. Start working on these after you have done all of the above you are able to do.

8. If you have any large windows without awnings, install awnings on those windows if possible. Awnings are one of the most effective ways to reduce heat coming into your coach. If your slide outs don't have awning covers, consider installing those as well.

9. Purchase a set of external sun screens for your windshield and cabin area. These are usually a set of four sun screens that cover your biggest heat gain windows. Use these screens whenever you are using your air conditioners. Any time you are parked with a view anywhere other than north, these screens will be highly effective. External screens are significantly better at reducing heat as they stop the heat before it comes through the window. Internal screens are more convenient but not as effective.

10. Purchase and use external sun screens to cover any other windows on the coach that do not have awnings covering them. Windows on the end of slides usually have no awning cover. They are usually small but still allow a significant amount of heat when the sun shine into the window. All windows without awnings should have sun screens.

11. Purchase foam board art panels (in the art supplies at Wal-Mart). Cut them to fit your windows. We cut several to height for a window and then stack them side by side, overlapping a little as necessary. Put them in the inside of the window valence during the day. Use them in rooms when you are not in the room. Put them in the windows when you leave the coach for the day. They will provide some additional insulation for the windows.

12. You can use the night to cool the coach to a much cooler temperature. This will get you off to a good start for the daytime temperature battle. Run the air conditioners through the night to bring the coach temperature to 65 degrees or cooler. It may mean living with cooler than comfortable temperatures at night and in the early morning. Keep the temperatures as low as possible during the morning and into the afternoon.

[Guest BillAdams]

Since this is a 2011 coach what has the dealer/manufacturer done so far and what is their current plan to resolve the issue. There is no chance that 2 A/C units working properly would fail to reduce the temp by more than 5 degrees.

[rorr1821]

I have a 2011 430qs motorhome, Charleston by Forest River, we have (2) 15,000-BTU Dometic Duo-therms that can't cool the coach when the o.a. is over 90*F.

Both units run on full power but can't make more than a 5*f. difference from o.a.

Is my only option to add another roof-top unit?

It is my understanding that a 430QS is a 42' tag axle 4 slide motorhome. If this is correct you have too much motorhome interior to cool for just two AC's, in my opinion. The general rule of thumb is anything over 40 feet has that third AC. This is not to say you do not have other issues with the current AC's. I am a big believer when there is a potential design flaw your best source is the factory service center if they have one. Unless you have an exceptional dealer they may not be able to resolve the issue.

[Guest BillAdams]

I could not disagree more. While more is certainly better, I cannot imagine any scenario where 2 15,000 BTU A/C units would only reduce the interior temp by 5 degrees. While 3 might be better, 2 should do a dramatically better job than described here.

[FMCANationalOffice]

I could not disagree more. While more is certainly better, I cannot imagine any scenario where 2 15,000 BTU A/C units would only reduce the interior temp by 5 degrees. While 3 might be better, 2 should do a dramatically better job than described here.

I agree with Bill. Start at the beginning-- verify that the two A/C's you have are working properly.

You can start, even before taking it to a dealer. Get an A/C thermometer. Record temperature at the air return. Record temperature at the closest outlet with the A/C set to high. PLEASE LET US KNOW WHAT YOU FIND.

And absolutely the first thing to check is that the filter(s) are not clogged. Second is that the ducting is connected properly to the A/C unit.

Brett

[hermanmullins]

I agree with Bill. Start at the beginning-- verify that the two A/C's you have are working properly.

You can start, even before taking it to a dealer. Get an A/C thermometer. Record temperature at the air return. Record temperature at the closest outlet with the A/C set to high. PLEASE LET US KNOW WHAT YOU FIND.

And absolutely the first thing to check is that the filter(s) are not clogged. Second is that the ducting is connected properly to the A/C unit.

Brett

Brett, isn't there a number that a a/c unit will cool down x number of degrees below the ambient air? Yes the two 15,000 BTU units should cool down a 43 foot coach. If I had a 2011 new coach my dealer would be checking an checking and checking until I was satisfied. Keep us up on what you find.

[rorr1821]

Maybe I was not clear in my statement. I am saying I believe you have two problems. The current AC's are not working correctly that is a given if you only seeing 5 deg temperature change. Once you get that problem resolved I still stand by my previous statement. Based on what I believe is your current length and slide configuration, you do not have adequate number of AC's to handle a worse case temperature situation.

[Guest BillAdams]

The air going into your A/C return vents should be leaving through the exhaust vents (cool air) about 5 degree cooler than it entered. So if the air in the coach is 90 the air blowing from the vents should be 85. With time the air temp in the coach should be reduced to 85 and the air blowing from the vents should be 80 which would reduce the air temp to 80 and the air blowing from the vents should be 75 and so on and so forth until the air temp reaches the temp where the thermostat tells the compressor to kick out. The fan should run 24/7 (never use the auto setting) and the compressor will kick in and out as necessary.

[FMCANationalOffice]

Actually, barring extreme humidity, an A/C should be able to give a minimum of 15 degrees and usually 20 degrees F lower outlet than intake temperature.

Again, to the OP, please post temperature delta A/C intake vs outlet.

Brett

[Guest BillAdams]

Whatever the number, be sure that you are seeing a great volume of air exiting your A/C unit with a drop in temp. Let us know what the difference is and what the dealer says about fixing the obvious problems.

[Guest Wayne77590]

Inquiring mind wants to know why the fan should not be set to "auto."

Thanks.

[Guest BillAdams]

It's more efficient when you keep the air moving and not allow the heat to build up from the ceiling down until it finally hits the thermostat.

[Guest Wayne77590]

That makes sense, but it also will not hurt except for efficiency, right?

Again, just trying to get more edumacation.

[-Gramps-]

An outside windshield sun screen can drop the inside temp by more that 15 degrees....closed window curtains do not work as well, neither will an inside sun screen.

[vtbigdog]

I would also check your filters and also see if there are any obstructions in the filter area that is restricting airflow.

[rrlowther]

I know this is going to sound simplistic. But have you checked all the ducts to make sure they are open? Don't laugh cause it happened to me.