Basement air conditioner air flow

azloafer · 07-25-2010, 10:40 AM

We have followed and tried every tip in this forum to increase the basement air flow in our coach to no avail. Doors opened and closed, various air vents closed, filters with increased flow, etc. The unit and duct work was checked by a Winnebago/Itasca Dealer and found to be in good working order. The dealer said that all the basement air units are the same (weak) as far as the force of the air flow. They couldn't come up with any way to modify the basement unit to increase the flow when it is 100 degrees or higher. They did install a roof top unit to supplement the basement unit. The air really blows strong from the add-on unit and I wish the basement unit moved the air like the roof unit.

Has any Winnebago/Itasca owner in this forum found another way to increase the flow? Joe

Wayne M · 07-25-2010, 10:53 AM

Joe,
I have not had the problem with air flow for my 2008 Destination. On my control panel switch there is a control for "Auto" and "On." There is also a switch for the fan of "Hi" and "Low." I leave ours in the Auto, and Hi positions and the air flow has been more than sufficient. I also redirect the ceiling vents to blow where I want them to blow, and not against the walls where the temperature is higher.

I do understand about that 100 degree temperature. So, when one day of our trip reached that point I went to a hardware store and picked up a roll of "Astro-foil." I only have big windows on the driver side of the coach and I cut out an individually fit piece for each section of the window. It will even fit behind the screen with a little push on the screen, and clip back into place. The side of the window without the screen held the formed piece in without incident. When we traveled w put them between the couch and dinette, although they would store flat or rolled in one of the compartments. My gosh! What a difference it made in keeping the coach cooler.

I have read the reports on adding a roof system. Not a bad idea. Worse case scenario if the basement air went out would be less cooling, but you would still have the roof air, and a nice easy chair to sit in directly underneath.

Good luck.

Wayne M · 07-25-2010, 11:24 AM

Joe,
An afterthought.

Turn the fan on, move the fan switch from hi to lo and see if here is a change in flow (sound). If not, it could just be wired wrong.

Good luck.

ruppr · 07-25-2010, 12:39 PM

Joe,
Absolutely no problem with air flow from basement air, so don't quite understand dealer's comment. Never been in one that didn't have strong air flow. However, basement air is susceptible to air leakage (and loss of cooling) on the vertical duct running from the unit up the rear cap to the ceiling ducting. You need to check for cold air leaking in this area. Several threads on this site about checking and repairing.

My unit had developed a bad leak where two sections joined together, (tape had turned lose from vibration/movement) didn't realized that was the problem but had noticed unit was running full time in hot part of day. Repaired joint (not the easiest thing) and unit now cycling again. (also more air flow)

Best,

ruppr

azloafer · 07-25-2010, 03:37 PM

Quote:

Originally Posted by Wayne M

Joe,
I have not had the problem with air flow for my 2008 Destination. On my control panel switch there is a control for "Auto" and "On." There is also a switch for the fan of "Hi" and "Low." I leave ours in the Auto, and Hi positions and the air flow has been more than sufficient. I also redirect the ceiling vents to blow where I want them to blow, and not against the walls where the temperature is higher.

I do understand about that 100 degree temperature. So, when one day of our trip reached that point I went to a hardware store and picked up a roll of "Astro-foil." I only have big windows on the driver side of the coach and I cut out an individually fit piece for each section of the window. It will even fit behind the screen with a little push on the screen, and clip back into place. The side of the window without the screen held the formed piece in without incident. When we traveled w put them between the couch and dinette, although they would store flat or rolled in one of the compartments. My gosh! What a difference it made in keeping the coach cooler.

I have read the reports on adding a roof system. Not a bad idea. Worse case scenario if the basement air went out would be less cooling, but you would still have the roof air, and a nice easy chair to sit in directly underneath.

Good luck.

We have added the roof unit but have not had a chance to test it under conditions of full sun and high temperatures. I'll say this much, the air really blows from the roof unit. Way, way more than the basement unit! Joe

azloafer · 07-25-2010, 05:45 PM

Quote:

Originally Posted by ruppr

Joe,
Absolutely no problem with air flow from basement air, so don't quite understand dealer's comment. Never been in one that didn't have strong air flow. However, basement air is susceptible to air leakage (and loss of cooling) on the vertical duct running from the unit up the rear cap to the ceiling ducting. You need to check for cold air leaking in this area. Several threads on this site about checking and repairing.

My unit had developed a bad leak where two sections joined together, (tape had turned lose from vibration/movement) didn't realized that was the problem but had noticed unit was running full time in hot part of day. Repaired joint (not the easiest thing) and unit now cycling again. (also more air flow)

Best,

ruppr

Put it this way, the air flow from the new roof unit is really blowing, while the basement unit isn't anywhere near the force of the roof unit. If the basement unit moved air as fast as the roof unit, I wouldn't have had to do anything! That's the best way that I can describe it. The ducts were checked by the dealer when they installed the Coleman roof air. Of course, Winnebago is going to roof units in 2011 from what I have read on the this forum. Joe

azloafer · 07-25-2010, 05:56 PM

A quote from John Canfield on another forum: On the new 42QD, the ceiling ducting from the three roof airs is a formed duct with smooth walls which will greatly contribute to increased air velocity. The Styrofoam ducting present in most other models has rough walls which increases air turbulence. John seems to know what he is talking about. Joe

DancinCampers · 07-25-2010, 06:49 PM

I looked at some new units with roof air at GNR. I am concerned how they will work over time. The return air uses ceiling ports similar to the outlets. When you look at the ceiling, there are 2 rows of ports down the length of the coach. One side is outlet, the other side is the return. Each return port snaps in place, is removable and contains a small circle of coarse foam filter material. My guess is you remove these and clean them under water.

I did not see any other filters.

This was in the high end coaches, I did not check the lower end ones.

mrschwarz · 07-26-2010, 04:15 AM

I had basement air on my old Suncruiser 33. It worked fine and always cycled, even on hot days. My new nearly 38' Meridian with dark sides (and maybe not quite so good insulation) and a lot higher inside ceiling has a lot more cubic feet of living space. I also has the same size basement air that doesn't appear to be adequate for the size of the unit.

Winnebago says it is, but they know a lot of people that have added a roof air. I have already added front screens for a minimal improvement. I am about to order window awnings and a roof AC unit. That should get it below the 80s on a hot summer day.

I think the reality is that there are not enough tons of AC for the size of the coach. It's obvious the AC was sized to the available model and basement air was a marketing opportunity that trumped cooling requirements. Oh, well. Maybe next time, I'll insist they put the coach in an oven and demonstrate the cooling ability or only buy a new motorhome in south Texas in the summer.

McDuff · 07-26-2010, 07:50 AM

Quote:

Originally Posted by azloafer

We have added the roof unit but have not had a chance to test it under conditions of full sun and high temperatures. I'll say this much, the air really blows from the roof unit. Way, way more than the basement unit! Joe

My guess is, if you ducted the roof ac the length and turns the basement ac goes thru, you would find that it didn't flow any more, and maybe not as good as the basement ac. Would take a huge blower to try and match the output of an unducted model.

But I am with you, my basement doesn't keep up. Just spent a week in Key West and I had to start the days cooling early to try and "get ahead" of the sun. We were lucky to keep it in low 80's this way.

You've got me thinking of adding a 3rd ac now.

cryoman · 07-26-2010, 11:49 AM

I had a similar proplem with my 35U, on the back of the bed where the return grill is our bed cover was hanging down and was sucked in next to the grill. Now we tuck that under the mattress and all is well.

two2go · 07-26-2010, 01:10 PM

Not in a Winnie product, but we have the basement a/c. Sitting here right now under clear skies and 95 deg. and the a/c is blowing strong on low fan, holding 81 set point at the thermostat and 78 near the front. We have full paint with a white roof.

The basement units will deliver, so one would have to suspect the ducting design, obstructions, blocked intake or filter assuming the unit itself is charged and functioning per spec.

azloafer · 07-26-2010, 03:46 PM

Quote:

Originally Posted by cryoman

I had a similar problem with my 35U, on the back of the bed where the return grill is our bed cover was hanging down and was sucked in next to the grill. Now we tuck that under the mattress and all is well.

Our return is along the side of the bed and very close to the bed. That is something that I never thought to look for. What a weird place for the return. Maybe that is the culprit. Thanks so much; I am going to check for that as soon as I can. Joe

azloafer · 07-26-2010, 07:12 PM

Quote:
Originally Posted by cryoman

I had a similar problem with my 35U, on the back of the bed where the return grill is our bed cover was hanging down and was sucked in next to the grill. Now we tuck that under the mattress and all is well.

Our return is along the side of the bed and very close to the bed. That is something that I never thought to look for. What a weird place for the return. Maybe that is the culprit. Thanks so much; I am going to check for that as soon as I can. Joe

UPDATE: I went to check the coach and specifically the return register by the bed. Sure enough, about 2/3rd of the return was blocked by bedding. I fixed that and we will see what change that causes when we camp next time. Thanks for the help. Joe

Luv2go · 07-26-2010, 07:30 PM

Quote:

Originally Posted by DancinCampers

I looked at some new units with roof air at GNR. I am concerned how they will work over time. The return air uses ceiling ports similar to the outlets. When you look at the ceiling, there are 2 rows of ports down the length of the coach. One side is outlet, the other side is the return. Each return port snaps in place, is removable and contains a small circle of coarse foam filter material. My guess is you remove these and clean them under water.

I did not see any other filters.

This was in the high end coaches, I did not check the lower end ones.

Looks like Winnebago copied Newmar's duct design! This design has been used on all Newmars for a long time with no long-term problems

. You take out and clean the foam filters with water, as you suspected.

Stewart

Harry B · 07-26-2010, 11:38 PM

I am happy with the performance of my basement unit. However the RVP basement units are only 12,000 BTUs each that is only 24,000 BTUs total. Not a match for 2x 15,000 BTUs that you typically find on a 40ft coach.

I do like the reduced noise of the basement air during the day. I did put new deflectors on the ceiling which disperses the air sideways instead of down and that has enhanced the comfort greatly.

Wayne M · 07-27-2010, 10:27 AM

Darn! It's always the little things in life.

Sure glad it's not the big things.

Good find. Let us know how the next trip is Joe.

p.s., change the filter at least monthly and sooner if it appears real dirty.

azloafer · 07-28-2010, 07:24 PM

Quote:

Originally Posted by Wayne M

Joe,
An afterthought.

Turn the fan on, move the fan switch from hi to lo and see if here is a change in flow (sound). If not, it could just be wired wrong.

Good luck.

I was fooling with the controls at the "one place" unit. One puzzling thing is the fan speed. When standing at the controls, I can watch the amp meter and switch from low to high while holding my hand near one of the AC outlets. As I switched the fan speed from low to high I couldn't detect any increase in sound or feel an increase in air flow, BUT on high the amp meter goes up about one amp. Maybe I am expecting too much of a change, but I did it over and over and the only thing that I can see is a difference in the amperage used . Something is changing to account for the one amp increase, but I can't tell what. Maybe I'm getting old and hard of hearing. I'll test it again with my DW listening for a change. Joe

Hikerdogs · 07-29-2010, 08:03 AM

Our coach is a little older but has the same basement air. When we switch the fans from low to high there is not a huge difference in airflow and fan speed but it is noticable. Like yours our amp reading increases 1 amp between low and high speeds.

For the first time in 10 years we noticed poor air flow from the ceiling ducts. It also sounded like the fans were laboring. I went to the bedroom to find the bed spread had slipped over about 2/3 of the air inlet. When I pulled it off the grill the fan speed and air flow increased considerably. Funny how we could go so long without a problem then find several others who had the same experience.

MrTransistor · 07-29-2010, 10:44 PM

Hello azloafer,

My take on your problem is “your Winne dealer is lying to you”. My guess is that you paid them to check out your AC and what they did is slide it out just enough to look inside. Had they pulled the unit out and set it on supports my guess is that they would have found a mat of lint covering the evaporator, which causes the problems you are having. When properly cleaned, the cold air blowing from the vents is too much to sit under. The force of air is quite noticeable from low to high.

Ours was just like yours for the last four years. Very poor airflow, no detectable difference between low and high, and difficulty with cooling the coach. We have been full timers since the coach was new and it degraded so slowly that I was unaware of the problem. After reading other posts recently, I decided to pull the unit for cleaning. Thank goodness for my son’s muscles. While it was out, we blew all the dust out of both sides, straightened a few outside fins, and removed all the lint that had built up on the evaporator. It was about 90% covered with a solid mass about 1/16” to 1/8” thick and the last 10% had a thinner layer covering it. It took over two hours and I had to run the engine for ½ hour for compressed air.

I was blown away at the difference, its borderline too noisy and like mini tornados at each vent. It’s even tricky to get each vent pointed just right so it’s not blowing on me sitting at the computer, and that’s on low.

Of course, it could be a loose setscrew. But that’s my take on it.