Air8 Performance in T@B 400 & Resolution (Coming Soon!)

TNOutback

I will say upfront that while I’m loving this camper already, I think NuCamp has made a mistake with the Air8, and I believe it is undersized for the T@B 400.  Bright sunshine, 91 degrees at 1:30PM outside, camper in full sun.  The air conditioning has been running for 2 1/2 hours in the T@B, all window shades closed, refrigerator is OFF, and the best the a/c can do is bouncing between 78-81.5 degrees.  The temperature at the nozzle closest to the unit under the bed is 66.2 degrees; the nozzle above the bed is 67 degrees, and the nozzle up front at the dinette is putting out 68.7 degree air.  Nominally a 9-11 degree difference.  Should I expect better performance?

jgram2

We crack the fantastic fan, turn it on a low setting and crack a window which helps circulate the air. We have the smaller Outback-boondock, but that works well for us. Gets to 72-74’ in 1-1.5 hrs with ambient temps of 95-98’ and 85-90% humidity. OEM 5000 Frigidaire  ac. I wonder if measures to promote air circulation would help with your 400?

TNOutback

jgram2 said:

We crack the fantastic fan, turn it on a low setting and crack a window which helps circulate the air. We have the smaller Outback-boondock, but that works well for us. Gets to 72-74’ in 1-1.5 hrs with ambient temps of 95-98’ and 85-90% humidity. OEM 5000 Frigidaire  ac. I wonder if measures to promote air circulation would help with your 400?

Forgot to mention I did slightly open the fantastic fan vent and turned it on the “1” setting to pull out hot air.  Not only has that not worked, the temperature is now up to 81.5 degrees per the Air8 control panel.

VictoriaP

I would start by looking under the trailer at the vents for the AC unit. If they have louvers, the trailer has not been fixed under the service bulletin for the Air8. The vents should be covered with hardware cloth instead (wire mesh) if the service has been performed. Some have found that additional baffles to separate exhaust from intake have helped significantly. There’s a whole thread around here somewhere just on the Air8 issues that should be helpful.

TNOutback

@VictoriaP the trailer has the “modified” a/c vents underneath; no louvers. 

VictoriaP

TNOutback said:

@VictoriaP the trailer has the “modified” a/c vents underneath; no louvers. 

Definitely search for the Elwell Air8 thread then. You may benefit from the baffle structure that another user had their dealer create and install before nuCamp came out with the modified vent covers.

TNOutback

I hope I’m wrong, but trading out a 10,500 btu Cool Cat for a 6,000 btu Elwell Air8 may have been a mistake by NuCamp.  Maybe this is what happens when you give up 42% of your cooling capacity.

I also have noticed that a posting back in May by @Arizonayeti said his Air8 manual said it had a nominal cooling capacity of 8000 btu, but my manual says 6000 btu. Hmmmmm......

Arizonayeti

@TNOutback  I'll have to go back and look at my Air8 unit again and where I got the 8000 btu number from.  If you go to the Truma.com site you'll find the specs for the Saphir Compact (Air8) at 1800 watts which is roughly 6100 btu. I does appear to be undersized for the 400, but probably just right for a 320.  I wish I could give you some real-world performance data like @BigShowSkipper has, but unfortunately, my Air8 hasn't worked since May and we have yet to get a replacement unit.  

Cbusguy

I will say the AIR8 is barely adequate for my camping needs, Keep in mind we have a 320.  Now I haven't been anywhere that I consider really hot and humid.  Mostly Ohio, Kentucky,  Indiana and Pennsylvania summer weather.  We have camped a few days where the the temps were in the mid 90s.    

I have no doubt that if that AIR8  won't keep a 400 cool in direct sunlight.  Makes you wish they did a bit of performance testing before they just make changes.     Ours never shuts off during the day,   with the temp in the camper set to 78 degrees,  just runs and runs.   

I honestly believe the owner group is nucamps R&D department and now we have branched out into performance testing as well.

TNOutback

I don’t disagree @Cbusguy. I’m going to test some more with another thermometer, and see if deflecting the exhaust makes any difference . In the afternoon sun hitting the door side , I was only getting an 8 degree difference. My initial thought is the Air8 is undersized for the 400. If I had known that up front, I would have worked to find a 2019 unit, or hold off on purchase to let them sort it out. 

TNOutback

Tried again today but used the constant max speed fan setting instead of the automatic fan setting (see other post about Air8 turning itself off every 3 minutes).  This time, starting inside temp was 95 degrees late afternoon after the sun was completely off the camper for two hours.  4 1/2 hours after starting the a/c, the inside temperature had reached 79 degrees according to two different thermometers.  Interestingly, the temperature displayed on the Elwell thermostat was reading 71.6 degrees.  (At this point the outside temperature is 80 degrees.). The two independent thermometers were sitting on the kitchen counter, about 4 feet away from the Elwell thermostat.  It’s hard to tell if the Elwell unit is truly off that much, or more likely, it is showing the effects of the a/c vents blowing directly toward the thermostat.  (The vents under the bed and under the dinette both unfortunately, blow directly at the thermostat if they are turned upward.)

Vent temperatures were 60.1 degrees under the bed, 63.4 above the bed vent, and 66.0 degrees at the vent under the dinette.  Those outlet temperatures seem reasonable.

So 6 1/2 hours after the camper is out of the sun, the best the a/c unit can do is 79 degrees in the cabin.  It sure seems like this unit is undersized for the T@B 400, and that is very disappointing to say the least for such an expensive camper.  I really like our T@B 400, but this new a/c unit is a fatal flaw as far as I’m concerned and makes me second guess our purchase decision.

Sharon_is_SAM

The output temperatures are encouraging @TNOutback.  It does appear that the thermostat is impacted by that direct hit of cool air.  Maybe try to use a fan on the floor to circulate the air upward rather than direct the vents upward.  Although it took a long time to cool it down, I am not surprised.  Elwell specifies that the Air8 works best if you start with a trailer in the shade - that means a trailer that is not already heat laden.  

Have you read the FAQs from this website?  Scroll down closer to the bottom.  

https://www.truma.com/int/en/products/truma-air-conditioning/truma-saphir-compact.html

Basically it assumes that an RV has better insulation than a car and they report that the Air8 will produce a maximum temperature difference of 10 C (18 F) under optimal conditions (RV has been kept cool in the shade, all windows/shades are closed and the humidity is low, warm air has been exhausted).  They specify that the indoor vs outdoor temp difference should not be too large and to prevent condensation on the equipment, it is best to close all doors and windows.  



How do I cool my caravan or motor home especially effectively?

You can keep a cool head at any temperature by following the tips:

• Before starting the system, check that the camp site has adequate fuses (min. 4 A).
• Position your vehicle in shade if possible.
• Closing blinds reduces heat radiation.
• Clean your roof at regular intervals – dirty roofs are hotter roofs.
• Ventilate the vehicle properly before starting the appliance in order to remove accumulated warm air from the vehicle.
• To obtain a healthy indoor climate, the difference between inside and outside temperatures should not be too large.
• During operation, the circulated air is cleaned and dehumidified. Dehumidifying moist air creates a pleasant indoor climate even if the temperature differences are not great.
• When cooling, close all doors and windows so that no condensation forms on the air distributor.

Why does a Truma air conditioning system not have the same cooling output as a car air conditioning system?

In many cases, air conditioning systems are used in cars for just 20 to 30 minutes. A comfortable temperature of about 23 °C should be reached within a very short time. Because cars often have dark colours inside and outside and angled windows, such as the windscreen, they heat up very quickly. This is why car air conditioning systems are equipped with a high cooling output (6 to 8 kW). They are much more powerful, as the compressor of the air conditioning system is driven by the car’s engine. This explains why the engine loses power when the air conditioning system is switched on in the car.

On the other hand, RVs are often used for several hours. The air conditioning system is also used over a long period (while driving or at the camp site). Light external colours and steep windows reduce heating of the vehicle compared to cars. The cooling output of air conditioning systems in RVs is generally much lower, as they are electrically operated and the power supply is limited. This is why a high level of energy efficiency, which ensures optimum cooling output with low power consumption, is essential.

Our air conditioning system can produce a maximum temperature difference of 10°C under optimum conditions, such as when the vehicle is in shadow, is darkened, windows and skylights are closed and humidity is low.

TNOutback

Thank you for the link, @Sharon_is_SAM. The issue I can’t resolve though is that first night after arriving at the campground. Roadways are not shaded, so while traveling on your camping trip, you can’t avoid the sun and you are going to arrive with a hot camper. It’s going to be a miserable first night if you are camping in the summer.  By their definition, “optimal” does not include towing your camper to a campground.

Sharon_is_SAM

I know.  Ours TaBs are heat sinks.  I tried using Reflectix on all the windows while traveling this summer and I monitored the inside temperature.  It remained at ambient, so the roof is the culprit.  I have not tried traveling with our MaxAir vent open as others do.  

Cbusguy

18 degree temp drop,    Probably what I am seeing,  but I never actually took a thermometer and measured it.     it was 96 degrees according to weather bug,   dont recall the humidity,    the trailer was 78-79 according to the air8 thermostat.    So it is functioning as expected.    

water was steady dripping out of the exhaust vent,   with what I just read,  I am not sure that is okay or not,  you would think they would need to drain condensation

not the end of the world,  but not stellar performance either.   

TNOutback

I’ve always been leery of traveling with a roof vent open since there isn’t much structural support when it is open and didn’t want to arrive with a ripped off vent cover. I understand the tongue weight issues with the Cool Cat up front, but the trade off doesn’t seem worth it to me. 

TNOutback

@Cbusguy that Airwell may be sufficient for the smaller 320, but my observations thus far in the 400 are that it really struggles. 

DougH

I don't have the 400 or Airwell, but didn't someone find a Truma manual reference that stated that the intake and exhaust should be separated by a structural member?  Perhaps if the exhaust had been routed to forward of the axle, with intake well to the rear, it might be more capable of approaching the 18F maximum differential.  But still, only getting 10F because of direct sun when it's 98F out doesn't seem to be enough.

Cbusguy

@TNOutback I would never travel with the stock fantastic fan lid open, and I would agree that it seems to fragile.

Some members have changed the fantastic fan for the Maxx fan which is designed to be open during travel and can be left open during rain.    

On my 320 the intake and exhaust are separated by the frame,   but I doubt that would matter as the louvers do a nice job separating the intake and exhaust.

I am not sure who made the decision that a roughly 20 degree temperature drop was sufficient for any of the the trailers,   seems it wasn't investigated very well.

TNOutback

The “modified” screens on the 400s seem to be sufficient as the outlet temperature I’m seeing on the shortest run from the unit was 60 degrees, a reasonable outlet temperature.  What is not accounted for in the change to the Air8 is the loss of BTUs: the capacity to remove heat from the space.  I’ve never experienced the performance of the Norcold Cool Cat units, but it was rated at 10,500 BTUs.  The Elwell/Truma unit is rated at 6,000 BTUs.  The ability to cool is almost cut in half.

Interestingly, Truma has a slightly larger version of the one in the T@Bs called the “Saphir Comfort RC”, which is an air conditioner/heat pump combination that is rated for 8100 BTU in cooling mode.  The unit has the same width and height dimensions and is only 2.5 inches longer than the ones in the new T@Bs.

Also, the ductwork under the bed in the 400 makes a sharp 90 degree bend right out of the unit, and sharply turning the airflow introduces turbulence, that is, friction, thereby reducing airflow.

jgram2

@TNOutback I’m curious if those ac vents can be redirected like those in an auto (imagine you would have done so if they could be) or if you can fashion temporary diverters to test the possibility that redirecting the cooled air away from the thermostat would have a positive effect. Playing cards, aluminum foil, strips from a plastic cutting board, something? You might have to deal with “flapping” noises, but just for the duration of the testing period. If the direction of the cooled airflow cannot be changed, can the vents be unscrewed and repositioned? Might be easier to partially cover the thermostat. Would that it could be that simple.

N7SHG_Ham

Through all this AC shake up, wondering if anyone has heard of a solid reason to abandon Dometic? I know it was stated for the 400 the reason the AC was moved was weight, the Cool Cat in the previous 400's is around 70 pounds, a lot of that went to hitch weight, however the Air8 has to weigh something so it didn't reduce overall weight by 70 pounds.

It is possible that the Cool Cat physically would NOT fit under the bed, thus a new vendor was found? It seems that new vendor had a unit that fit, but maybe only because way less BTU's?

I can also understand NuCamp sourcing a single vendor for all models, that makes perfect sense.

What doesn't make sense is a knee jerk reaction to hitch weight without some research and testing. While I like the mostly good quality of NuCamp products, mechanical and electrical engineering seem to be very weak areas. Every design change needs to be considered for what other systems may be affected and not convinced that is happening at an acceptable level.

TNOutback

I like the location for the new a/c unit, just not the power!  The Air8 is certainly smaller dimensionally.  Freeing up that space under the dinette seat is now a huge storage area!  I am perplexed though why NuCamp didn’t choose the higher capacity 8,000 btu Truma model; surely they could have found a way to accommodate the 2.5 inch greater length.

jameskuzman

Two things stand out as red flags to me from the Trula information:

1) "To obtain a healthy indoor climate, the difference between inside and outside temperatures should not be too large"

2) "Our air conditioning system can produce a maximum temperature difference of 10°C under optimum conditions, such as when the vehicle is in shadow, is darkened, windows and skylights are closed and humidity is low."

The first is simply absurd. If there was little difference between the outside temperature and the desired inside temperature, you wouldn't need an air conditioner in the first place. I interpret this as a pre-emptive explanation for an under-performing system. 

The second seems reasonable at first blush but things fall apart quickly when you get to the conditions under which the results can be achieved. If the desired indoor temperature is 70 degrees, for instance, that means the system can achieve it as long as the outdoor temperature doesn't exceed 88 degrees. If it's 95 outside, you can get 77 indoors. That's fair. But that's with the camper in the shade, in the dark, with closed windows in low humidity. If the humidity was low and I was parked in the shade, I could be comfortable with a fan. Again, it sounds like they're laying out reasons why it will likely under-perform. 

Part of this could be cultural. This is a European system, and air conditioning isn't nearly as common in most of Europe compared to the U.S., so maybe a system with these specs is acceptable there. Witness the marginal A/C in any Mercedes-Benz. 

The Cool Cat was a proven performer, but the relatively heavy tongue weight on the 400 compared to the trailer's overall weight was a concern for a lot of buyers, so I can see why NuCamp wanted a different solution without having to completely re-design the camper. What surprises me is that they chose a system with these limitations and only 60% of the BTUs of the Dometic unit.

Not to add insult to injury, but my 2019 400 was sitting in my concrete driveway last week in full sun with the shades open with an outdoor temperature of 88 degrees and relatively high humidity. The temperature inside the camper was 95 degrees as indicated by the digital thermometer that came in the welcome pack. 45 minutes later, the digital thermometer read 68 degrees - a 27 degree Fahrenheit and 15 degree Celsius difference.  

Sharon_is_SAM

"Also, the ductwork under the bed in the 400 makes a sharp 90 degree bend right out of the unit, and sharply turning the airflow introduces turbulence, that is, friction, thereby reducing airflow."

Would a computer fan in that duct help at all?

TNOutback

Sharon_is_SAM said:

"Also, the ductwork under the bed in the 400 makes a sharp 90 degree bend right out of the unit, and sharply turning the airflow introduces turbulence, that is, friction, thereby reducing airflow."

Would a computer fan in that duct help at all?

Not coming out with 90 degree bends would help. Arguably not much room in there though.  Just lose some airflow efficiency with an already undersized system. 

Cbusguy

@jgram2 if it is the same as the 320 then yes,  you can close them completely and rotate the deflectors 360 degrees to put the air where you want it.

jgram2

@Cbusguy Thanks.

ChrisFix

TNOutback said:

I will say upfront that while I’m loving this camper already, I think NuCamp has made a mistake with the Air8, and I believe it is undersized for the T@B 400.  Bright sunshine, 91 degrees at 1:30PM outside, camper in full sun.  The air conditioning has been running for 2 1/2 hours in the T@B, all window shades closed, refrigerator is OFF, and the best the a/c can do is bouncing between 78-81.5 degrees.  The temperature at the nozzle closest to the unit under the bed is 66.2 degrees; the nozzle above the bed is 67 degrees, and the nozzle up front at the dinette is putting out 68.7 degree air.  Nominally a 9-11 degree difference.  Should I expect better performance?

I really hate to hear this - I was getting set to order a 2020 T@B400 in two months...but we really need an air conditioning system capable of cooling better than what you're reporting. I have to agree with the general sentiment that 6K BTUs is just not big enough for the T@B400. I do really hope Nucamp responds with an improved solution very soon.

TNOutback

Tried another test today.  We had a front come through yesterday and cooled us off and have much drier air.  Camper was 66 degrees this morning.  I turned on Air8 maximum fan setting and set the thermostat for 70. (It appears the Elwell thermostat is about 9-10 degrees off the actual air temperature.). By 10:00AM this morning the inside temp was 78; by 2:00pm it is 80.  The Air8 thermostat is reading 70.7 degrees while the other two independent thermometers are 79/80.  At 2:00pm the outside temperature is 85.

So, starting off with a cool camper and starting the a/c early, I only have a 5 degree differential between outside and inside with the camper in full sun.  It will not hold temperature starting off with a cool camper.  NuCamp has made a mistake with this air conditioner; it is simply undersized for this camper.  That’s a lot of $$ to pay for a camper you cannot use comfortably in the summer.

rbtx

I sure appreciate your posts here - it is very painful to read about this for your new purchase and knowing this could have readily been us if we had moved forward faster. Most of our initial thoughts for using this camper were weekend trips here in Texas.  We would surely be suffering in the heat and upset. I thought such a small volume would be easily cooled and not something overlooked by the design team.  NuCamp has to step up on this one.