Basement Air - 2008 Meridian

[mrschwarz]

There is another discussion about the basement air in a '10 Horizon, but instead of hijacking the thread, I am posting my frustration here. I'll leave it to the moderators to decide if the discussions need to be combined into one or not.

I complained last year about my coach cooling and have done a little research that was very surprising. When I bought the coach, it went back to the dealer more than once about it and the report back was that the system was operating properly and nothing needed to be done.

The temperature differential is about 20° which is what everyone reports it should be. The only problem is when the return is 75 and the ducts are 55, the coach is hot. I'll be fine when the return is 65 and the duct is 45 (or less)!!

1. I'm currently in Gulf Shores, AL where it was about 90 yesterday, but the humidity was killer. The AC was running when I arrived and didn't stop until the sun went down. Even though it was set at 78°, the thermometer read 80, 82, 84 as the day wore on. I have a Progressive surge protector that gives me current draw on both legs of my 50 amp service. When it was running, the first leg pulled 10 amps and the second was pulling 26 amps. That surprised me. With both compressors, I would have expected more than a 10 amp draw. According to the nameplate on the RVP unit, min. circuit ampacity of each stage is 19/16/6 amps, respectively. If one led is only drawing 10 amps, even if nothing else is on that leg, it should have read more than 10 amps. I am going to run the generator and mess with the Thermostat to see if I can see one and both compressors engaging.

2. I have noticed that when I am traveling, the temperature on the thermostat doesn't reflect my opinion of the actual temperature in the coach. It reads much higher than the temperature seems. I bought an inexpensive infrared thermometer. The temperature at the drivers seat is sometimes 10 degrees less that the temperature at the thermostat. In my floor plan, the One-Place control panel is located behind the LCD TV cabinet. The cabinet contains the satellite receiver and stereo. Underneath is the water heater and storage. The bathroom is on the other side of the wall.

I am guessing that there is no insulation in there. That's why the thermostat already reads higher when it's hot outside. I am guessing in the winter, I have the opposite problem. I have been in there to run wires to the bedroom TV and surge protector, and didn't notice any insulation. At the time, I wasn't thinking about it, but I'll bet if I stuff a whole lot of insulation in there, that's going to help the heat load as well as the accuracy of the thermostat.

My wife, who is sometimes subject to 'power surges' sensitive to the temperature () got her hands on the thermometer and was checking the temperature of everything on the inside. She found that the temperature of the LCD TV screen, when it was on, was 94°! At the time, it was on because we were listening to music on the satellite receiver. That got shut off in a hurry. She also found that inside one of the wall mounted cabinets, on the sunward side, the wall temperature was 106! I am guessing that the wall insulation can not handle the sun load.

Here are the steps I plan to take to improve coach cooling in the order I am going to take them.

1. I am going to verify that both compressors in the AC are running using something other that the surge protector current reading (when I have been connected to 30 amps, the EMS and surge protector sometimes have a 'disagreement' about the current draw.

2. I am going back inside the cabinet behind the One-Place and am going to stuff as much insulation in there that will fit. Also, I will insulate the back of the One-Place panel (to protect from the heat of the TV).

3. I am going to get darkening screens for the windshield and windows. The Windows are tinted, but knocking down some more sunlight couldn't hurt.

4. I may invest in window awnings. (see comment on #3).

5. I may get some styrofoam insulation for the cabinets. I am not sure if they'll reduce the load enough to justify it. I'll see what happens with 1-4.

6. I have a roof vent in the kitchen area. I also have a range hood that is vented to the outside (another source of heat). Seems like a dandy place to drop another AC unit to help keep up with the load. I'll need to figure out how to drop the power into the electrical compartment and may either wire it into the main panel or use the 20 amp plug in most power pedestals (or both).

I live in the Dallas area, so I'll have plenty of opportunity to test the heat load. I'm on a quest to get this thing cool!!!!

I'll report back what progress I make.

[smlranger]

Michael:

You are not the first to be less than pleased with the ulitmate cooling ability of some Winnebago coaches. Unless they have changed the design recently, there is no insulation in the inside top of the front cap and none in the roof radius.

I would say the hottest locale we frequented was at the IRV2 National Rally in Branson, MO 3 yrs. ago. It was very hot (mid to upper 90's), fairly humid, and we were in full sun for most of the week. I can tell you that the black windshield screen (Sunshades), window awnings and insulating foil in the shower skylight and the roof vents helped much. As you noted, the basement air compressor ran nearly constantly during the day but we were able to keep the temp inside at about 75.

Let us know what you discover about your basement air and how well the other things you try help.

[MrTransistor]

Hi Michael,

This is one way we reduce the summer heat load in our coach. Works great in the winter also. These insulating pads are made of two thicknesses of a product called ‘Warm Window’ which claims better than R7 per layer. That makes R7 + R7 + R1.3 as compared to the plain glass at around R1.3. I sewed these curtains as well as: one each for the large bedroom window, small bedroom window, bathroom window, the skylight above the shower, and each Fantastic Fan. The snaps were fairly easy as well.

May I also suggest another thing for your list might be to check air flow to be certain that it is not being slowly restricted by ice buildup. Ours will almost stop cooling with almost no airflow if the humidifier is accidentally turned on in the daytime. At night, when the unit is cycling, it melts the ice between compressor cycles if the fan is left on. I was originally under the impression that the RVP system was designed to detect ice buildup and cycle briefly to the heat pump mode to eliminate it but that does not seem to be the case.

[mrschwarz]

Thanks for the responses. The roof radius thing explains the temperature in the overhead cabinets. I am going to try some foam board to see if this helps. I am a little hesitant to seal all the windows with insulation. It would make it too cave-like.

I discovered also that the slider seals seem to be very efficient at passing heat. They feel hot to the touch and measure in the 90s.

I changed the return air filter yesterday. It was filthy, which surprised me. I changed the return filter in my Suncruiser once a year and when I did, it looked fairly clean. I'll see if the filter change makes any improvement. I can check the temperature differential, but I am not sure how I would check the air flow.

In other threads, I read about periodically dropping the AC unit for a thorough cleaning. They also mentioned performing bearing service which in there. There is nothing in the owners manual about this.I was quite surprise to see oil cups inside the unit if there is no recommended service interval. Is this a consensus thing? I bought my unit new last year, but the dealer spent a year and a half trying to sell it before then. I don't know how many hours are on it (maybe an hour meter on it would be a good idea). Should I consider dropping and cleaning it?

My investigations over the last couple of days showed that the problem is not as severe as I originally thought. Even though the temperature at the thermostat read 82°, in the living room it varied between 76 and 78. If there is a local home depot, I'll insulate the panel and compartment. That should take care of the temperature differential, as well as one heat source.

[MaverickBBD]

Let me start off as stating that my basement air works fine. Three years ago when we were in Missouri relatives came to visit and had to go to their cars to get sweaters. My DW says it is cold enough to hang beef in here. A couple of thing I do is, window awnings and shades are a must. I believe it is easier to keep it cool then to cool it down. So run with dash air and when stopped fire up the generator. Always listen closely for the second compressor to kick on. Make certain the drain is clear to remove moisture. Most importantly I discovered that the motor home lacks adequate circulation to get the cool air through out the MH. I place a fan on the windshield, one mid coach and use the overhead fan in the bedroom. Try circulating the air and see if that doesn't help.

[dstinch]

Hello, I agree with all the above. Also my mh is a 36 journey so if yours is a 40 footer i believe the basement air is the same size for all. we stayed in kingman az. for 2 months july-august last year 100 at midnight-100 at 7am, the sooner you turn on the air and get the mh cold the better it will be as the temps rise during the day. The 26 amps is the draw with both comp. running. We are happy with the basement air. We have a dog so we have to change filter once a month. One last thing, u should just turn the thermostate down 68-72 when it starts getting hot. if you set at 78 like u had it leave the fan switch on instead of auto, it will keep the air inside moving when the comp. cycles on and off. (not get so stuffy). Have fun Don

[Thudman]

I'm near Perry, GA, arrived yesterday in 100* heat & 110% humidity. Setting up was a real joy. Temp in coach was 92*, both compressors running. This morning outside temp was 72* inside 76 & set at 76. Temps rose to 96 outside; OnePlace temp now inside is 88* (89 outside). I think the OnePlace ambient temp reads about 4-5* high.

Recently did the rear duct-sealing trick (separate thread), so I think the system is overwhelmed (& a tad old); and has difficulty cooling 38 feet of RV w/2 slides.

Had the same non-cooling problem at home in Destin. Miserable. My next rig will have three roof airs (unless I move to Alaska).

Tomorrow I leave for NC mountains, so will have some relief for the summer.

Thudman

[smlranger]

If you otherwise like your rig, you might consider adding one 13,500 BTU roof air in the midship roof vent. I know of at least one Vectra owner who is doing that now. Mounting it in the opening would be pretty easy but you would have to run a 12g romex wire to the unit and find a way to get it run to the breaker panel.

[Thudman]

I like my rig but not that much.

Thudman

[Don The Ham]

I had a cooling problem while camping in 90 temperatures this week in the NC mountains. Researching this web site reminded me of the duct seal problem. Found the seal between the HVAC duct and vertical duct open, resealed it and still had cool air flow in the rear cap. Found the vertical duct seem was had also failed. I removed the tail lamp to reach the failed duct area and resealed the vertical duct also using HVAC tape. AC now seems to be working per the specs listed in other posts.

[Thudman]

Further to my post above, yesterday I noticed no dripping out of condensate drain at bottom of basement A/C. I had run the A/C hard, about 10 hrs the two days prior while traveling (very hot!!). Went under RV to inspect drain tube & poked it. Water came pouring out for about 10 minutes. I estimate at least 5 (or more) gallons. I thought the darn thing was hooked up to shore water!

Maybe that was part of my cooling problem. Anyway I cleaned the tube with some Q-tips soaked in bleach. Lots of gunk, probably from road grime.

Thudman

[mrschwarz]

I was in Gulf Shores AL and the humidity was about 250% and didn't see any condensate. I thought it was just incredibly efficient and evaporated the condensate. I'll take a look at it. There are a lot of good suggestions in this thread.

I have already been doing most of the ones related to air circulation and thermostat settings. At Gulf Shores, all the shades were down, there was a reflective windshield cover and the front curtains were closed. During the day, I closed the bedroom registers and the bedroom door. When the temperature outside was 93° U was able to keep it at 76-78° inside. That's less than a 20° differential. I plan to add awnings and windshield screens (recommendations welcomed).

Driving home to Dallas yesterday, my outside thermometer at home read 105. The basement air was set to 72 and read 88. The dash air was on high and the windshield fans were blowing. It was maybe around 85° at the drivers seat. I am going to go looking for the guy that added the 3rd AC unit. I am not optimistic that the other things I do are going to overcome a deficiency as great as this.

What was Winnebago thinking? How do they test their designs?

[KIX]

Quote:

Originally Posted by Thudman Water came pouring out for about 10 minutes. I estimate at least 5 (or more) gallons. Thudman

If you had THAT much water inside the A/C unit it would definitely affect the cooling ability of the unit. Also, THAT much water most likely spilled over into the vertical supply duct elbow. Look very closely and feel the elbow for softness that would be caused by water soaking the insulated duct.

mrschwarz said: "When the temperature outside was 93° U was able to keep it at 76-78° inside. That's less than a 20° differential."

The 20* differential referred to is the difference between the supply ducts and the return air. It's not necessarily the difference between the inside and outside temps. Check the temps of the air coming out of the roof supply registers close to the A/C. Then check the temp of the air going into the air filter. The difference should be in the 20* range.

We have the basement A/C and for the most part find it performs well. That is providing going in and out the door is kept to a minimum in high heat/humidity areas.

[Thudman]

Thanks KIX, I'll check that elbow.

Thudman