AC ?

[dtzackus]

Hi. We have ducted a/c in our rig. I do not have the right owners manual for our a/c. What is the difference between ON and Auto for Cool? Thanks in advance.

[zenbuck]

We always run ours on ON to keep the cold air circulating. HVAC buddy tells me it is more efficient this way.

Agreed.... "On" will make your unit more efficient and will keep it from freezing up..

You picked the HOTTEST week Dan!! Stay cool and keep the beer cold!:C

[LarryJM]

Farm Camp wrote:


Measure the temperature of the air getting sucked into the intake, then measure the temp of the supply/output air and look for about a 20 degree difference. If that's what you see then the unit is most likely working OK. It may not have the capacity you need to keep the space at the temperature you want.

I'm assuming this rule of thumb still holds true. Maybe the new refrigerant and compressors have changed though. I was taught this little trick in 1983 LOL.

Right there is the key the A/C has little to do with what the outside temp is and this 20 deg delta often mentioned is across the Evap. How cold you can get the inside of the trailer is mostly dependent on the overall insulation and duct losses vs. outside conditions including sun and ambient temperature. You can get close to measuring the intake temp, but measuring the outlet at anywhere but right at the main air plenum will be somewhat higher due to ducting heat losses. This is why when it really gets hot outside those units with the factory registers off the main air plenum or those of us who have modified their ducting to add registers at or close to the main air plenum, can get increased cooling. Also a couple of small fans to circulate the air inside a trailer can also help cool the entire trailer some. A lot of folks think closing some registers to try and redistribute the air sounds like a good idea, but in fact can be counter productive since A/Cs need a designed minimum of free air register outlet to provide maximum cooling and most factory systems do not provide a lot of extra registers above the minimum required.

Finally our A/C units only come in basically two sizes, 13.5 and 15K BTU and generally only have one unit for the common 30A TT configuration and once above about 25' a 13.5K BTU single unit has two strikes against it from the get go and is always running to catch up in warmer weather.

Larry

[Mark_and_Linda]

We leave our ac set to auto during the day, on at night because DW likes the constant air. Cools well during the day, even in hot temps. We hardly ever set it to Hi.

[Farm_Camp]

Way - way back in the deep dark past when dinasours still roamed the earth I was taught a quick and dirty way to tell if a AC unit was working about right.

Measure the temperature of the air getting sucked into the intake, then measure the temp of the supply/output air and look for about a 20 degree difference. If that's what you see then the unit is most likely working OK. It may not have the capacity you need to keep the space at the temperature you want.

I'm assuming this rule of thumb still holds true. Maybe the new refrigerant and compressors have changed though. I was taught this little trick in 1983 LOL.

[dodge_guy]

Also when the switch is set to on it circulates the cool air to the bedrooms. when the temps are low enough and the air cycles on off and the switch is set to auto, it is possible for the closed rooms to not get cool. they will get stuffy unless the switch is on, on. this is what mine does if I set the switch to auto.

[CincyGus]

If you get 20 degrees difference between the outside and inside temps, your about average from what I have read. 25 and you're in the top 20% of performance.

[popeyemth]

The AC will only drop the outside temp so much. 96 degrees they all struggle that's why a lot have 2units. Keep the doors shut (don't run in/out) park in the shade use your awning put reflective material behind the (closed) curtains block your skylights .
Don't keep the fridge open much either they struggle too.
Campers are about compromise - you are not at home LOL 🙂

[dtzackus]

It is 96 F outside.....it seems like the a/c unit isn't getting cold enough. Cleaned the filter, it is cooler, but could be colder. Any suggestions besides leaving the freezer door open? Lol

[Jack_Diane_Free]

We always run ours on ON to keep the cold air circulating. HVAC buddy tells me it is more efficient this way.

[dtzackus]

Dumb question #2, would one get colder? My wife swears the ac runs colder on "ON."

[wildtoad]

Usually that refers to the fan setting. ON means the fan runs all the time, AUTO means the fan only runs when the compressor is running.

[mlts22]

On means the fan is running all the time, regardless of the compressor setting. Auto means the fan comes on and off.