How good is the CoolCat air conditioner in the TAB400?

rh5555

There has been a lot of discussion about the new AIR8 air conditioner that was installed in the 2020 TAB400.  Many people feel it is undersized.  It is certainly less powerful than the CoolCat unit, but was the CoolCat unit oversized to start with?  Let's find out...  Try to remember when you last needed the CoolCat to drop the cabin temperature by 25F compared to outside air (for instance it is 95F outside and you're maintaining 70F inside), which option best describes the Coolcat operation?

jameskuzman

I really don’t know which option to pick as how often it cycles on/off depends upon the outdoor temperature and how warm the inside of the trailer is when we turn it on, but I will say this: It seems to be ideally sized for the 400. The warmest it’s been when we’ve used it was the high 80’s with high humidity, and it had the interior down from nearly 90 degrees to 70 in under 90 minutes so it’s definitely not undersized. It also controls the humidity very well, so it’s not oversized either. We bought our 2019 400 this past August and the 2020’s were on the lot already; we chose the last remaining 2019 specifically because it had the Cool Cat and not the Air8, as our sales person (correctly) anticipated that there would be issues with the Air8. His advice served us well. 

N7SHG_Ham

Haven't paid enough attention to the poll questions to pick a specific one, my experience mirrors @jameskuzman, very adequate cooling with no issues, the Cool Cat just works correctly.

rh5555

@jameskuzman, good question!  Please select the option which best describes the operation once it has cooled the trailer down to an acceptable temperature when it is really hot outside.  I'm trying to determine if the CoolCat is more powerful than really necessary.  That it "works fine" doesn't answer that question, an over-specified unit will seem to work fine, it will just short-cycle.

jgram2

I’m curious @rh5555, there doesn’t appear to be a “just” right amount of power option. 

rh5555

@jgram2, I'm trying not to make this subjective.  One person's "just right" is another person's "over-powered".  I have my own view of "just right", which may differ from yours!

jameskuzman

@rh5555 - I completely understand that “just right” is subjective in terms of comfort. The home thermostat has been a marital battleground for years, and you just have look around any office to find half the people gasping for breath while the other half are bundled up in down vests! :-) 

But as @jgram2 pointed out, there’s no “just right” even by objective measurement points, only choices that suggest it’s inappropriately sized to one degree or another in either direction. That does not reflect my experience and so none of the choices are valid for me. If there were an option for “perfectly sized”, I would choose that. 

To be more specific, “perfectly sized” to me means a unit that is large enough to maintain at least a 25 degree temperature differential between inside and outside temps (so, 95 outside gets you 70 inside) and a unit that is small enough to avoid short-cycling the compressor and thereby failing to dehumidify properly.

For the cubic footage and insulation/loss values of the T@B 400, the 10,500 BTU Cool Cat is not at all over-sized - it is perfectly sized. The 6,500 BTU Air8 is undersized and would be even if the intake and exhaust plumbing was properly sized and placed. 

rh5555

I may be in a minority of one (probably am!!), but I would say a unit was perfectly sized if it could maintain a temperature difference to outside air of 25F while running all the time. I think I'll edit the poll to specify a condition under which the observations are made.  Thanks for the input!

jameskuzman

rh5555 said:

I may be in a minority of one (probably am!!), but I would say a unit was perfectly sized if it could maintain a temperature difference to outside air of 25F while running all the time. I think I'll edit the poll to specify a condition under which the observations are made.  Thanks for the input!

I'll be the first to admit that I am very heat intolerant ;-) As long as it can do a 25 degree differential, it can run and never cycle at all when it's approaching that spread. 

An interesting side note from another thread on the Air8: Irrespective of its installation in the 400 (or any specific installation for that matter) are the recommendations and expectations from Elwell: 

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

If the difference wasn't too large to begin with, I wouldn't need an air conditioner! 

"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."

32C = 90F; 22C = 70F (roughly), so that's reasonable, but that's under optimum conditions? I don't think so; It should do that under real world and worst case conditions.

Tundra57

I have a 2019 tab 400 with a coolcat. I would say it is overpowered for this reason:

I parked in slight shade. Outside temp 90. The sun was directly on my door which locally heated the coolcat thermostat. When I got back to the camper after 3 hours it was like a freezer. My dog was shivering. I think it was hardly cycling as thermostat was set to 70 but the temp there was 75. Elsewhere it was 65 or less.

I fixed that issue. However reading both other users of the ellwell and the manufacturers own admission their unit is way underpowered except in perfect circumstances. So from my experience I would say the expected rating would be somewhere in-between. However I would rather it got too cold than never cold enough. I can always turn it off and open a window. Being on vacation with no cool place to rest is no vacation for me.

A 10 degree max drop from outside to inside in shady conditions is too ridiculous for words.

Sharon_is_SAM

As I recall, the location of the Cool Cat thermostat near the door is not ideal as it over-represents the cabin temperature and ends up causing the Cool Cat to cycle more than necessary.  But, I would not call that being over sized.  @Tundra57, remind us how you fixed the thermostat.

Tundra57

I was just pointing out that it is well capable of cooling the Tab more than it would have to. Not complaining tho. It was just my layman's observation. I have not seen a post for the ellwell that said it got too cold EVER.

To solve the over cooling problem for me I now always park with the door away from the sun in shade if possible, always close the blinds and also I turned the duct outlet opposite the  thermostat to blow up toward the thermostat which helps to cool the door area. It does seem to help if you open the roof vent a little and turn the fan on very low. Crack the window by the Alde coolant reservoir ( so you don't suck the trailer flat lol). It moves the hot air away from the thermostat. I also added a 4 degree offset to the temperature using the temperature correction screen on the Alde. I have not had the problem since.

Camperboy

So talked to a rep at a dealership and found out the new Tab 400 have the Cool Cat. I regularly camp in 110 degree weather and need something that can maintain temp down to 70 during the day. Proper placement of the thermostat would be vital to the whole cycling issues. I will be interested to see what new owners are saying about the 2024 models.

Sharon_is_SAM

@Camperboy - following the 400 2020 model Air8, the CoolCat install resumed  in the 400 with the 2021 models.