Dash AC Temperature

[kcfrench]

I have a 38 foot Class A gas coach. We have been struggling with the dash AC. Within the year we have replaced the dryer and the compressor. Our mechanic tells us that about 62 degrees is as cold as it will get. Is he correct? If not, what temperature can I expect to read from a thermometer placed in the center vent on the dash on a day where the outside temperature is 85-90 degrees and sunny. Thank you for your help.

[wolfe10]

From Evans-Tempcon:

http://www.evanstempcon.com/tsg_guidelines.php

Air Temperature (F) Entering A/C Unit Inlet - Outlet Air Temperature Differential**

FRESH OR RECIRCULATED----LOW HUMIDITY---------- HIGH HUMIDITY

50------------------------------------------------5-10-----------5-10

60------------------------------------------------10-20----------0-15

70------------------------------------------------20-25----------5-20

80------------------------------------------------25-30---------20-25

90------------------------------------------------25-35---------20-30

100-----------------------------------------------30-35---------25-30

110-----------------------------------------------35-40---------30-35

** The outlet louver closest to the A/C unit usually discharges the coldest air. The warmest inlet air temperature (fresh or recirculated) should also be used for the Differential calculation.

[kcfrench]

From Evans-Tempcon:

http://www.evanstempcon.com/tsg_guidelines.php

Air Temperature (F) Entering A/C Unit Inlet - Outlet Air Temperature Differential**

FRESH OR RECIRCULATED----LOW HUMIDITY---------- HIGH HUMIDITY

50------------------------------------------------5-10-----------5-10

60------------------------------------------------10-20----------0-15

70------------------------------------------------20-25----------5-20

80------------------------------------------------25-30---------20-25

90------------------------------------------------25-35---------20-30

100-----------------------------------------------30-35---------25-30

110-----------------------------------------------35-40---------30-35

** The outlet louver closest to the A/C unit usually discharges the coldest air. The warmest inlet air temperature (fresh or recirculated) should also be used for the Differential calculation.

Just what I needed. Thanks

[hermanmullins]

From Evans-Tempcon:

http://www.evanstempcon.com/tsg_guidelines.php

Air Temperature (F) Entering A/C Unit Inlet - Outlet Air Temperature Differential**

FRESH OR RECIRCULATED----LOW HUMIDITY---------- HIGH HUMIDITY

50------------------------------------------------5-10-----------5-10

60------------------------------------------------10-20----------0-15

70------------------------------------------------20-25----------5-20

80------------------------------------------------25-30---------20-25

90------------------------------------------------25-35---------20-30

100-----------------------------------------------30-35---------25-30

110-----------------------------------------------35-40---------30-35

** The outlet louver closest to the A/C unit usually discharges the coldest air. The warmest inlet air temperature (fresh or recirculated) should also be used for the Differential calculation.

Good chart Brett. Aw for the days of R-12 and the Harrison Compressors.

[karenandcollins]

I don't know anything about the charts the others gave you. However, we recently had trouble with out dash ac. We had it repaired & it works great now. However, the guy who fixed it told us he is also an RV owner & when you're driving in 100+ temps, as we were, it's hard to keep cool with only the dash air. He said he puts a curtain between the driver section & the rest of the coach. We bought a closet pole & some drapes that matched the rest of our interior & put them up. It made a huge difference in the temp in the driver's cabin. Maybe that will help you if your air is working propertly.

[gibsonjv]

On cars & light duty trucks you should always use the recirculation setting on hot days. It is easer to cool cabin temps that are 60-90 degrees down to 45 than it is to cool 125+ degrees down to 45 with fresh air. fresh air usually comes from the inlet ducts around the engine compartment.

Having said that the A/C in my coach only gets about 48-52 degrees with recirc. 10-15+ degrees hotter on fresh air. The curtain works wonders. However I have also fired up the generator and driven with the front house unit on with no problems. I just don't like a curtain behind me.

[Guest Wayne77590]

Here's my story, and I'm sticking with it.

I have always stuck a thermometer in a vent, and when we purchased the MH it was no different. We started out at about 48-50 degrees on the first few trips. Then, after about 100 miles the temperature would start climbing up. When it go to reading about 65 I would start the generator and turn on the house AC. I'd shut the dash off. After 30 minutes I'd turn it back on again and it would be blowing down in the low 50's, but after a while it would start creeping up. Now this is a problem that could not be duplicated at the Freightliner Shop, but they said they fixed it. Ha! 1 year later it was still doing the same and I took it to a private shop. They found a split line at the vacuum control on the dash. I thought I had it fixed, but after a month or so it started doing the same thing. Back at the Freightliner shop the found a bad (can't remember) valve and something else and replaced it. On this trip it has been blowing at between 55 and 60 degrees.

It is strange that when I get in an automobile and put the thermometer in the vent it will blow a constant temperature around 45 degrees. Never did mater what the outside temperature was. Since the MH dash was blowing real cold at one time in 90+ degrees, why shouldn't it do it now. All the charts in the world will not convince me that the temperature blowing out of the dash should not be a constant 45-50 degrees.

Now granted, you may not be able to cool down a 400 square foot area with just the dash AC, and THAT could be a product of the chart, whereas the temperature inside will only be about 15-20 degrees cooler than the temperature outside.

Now when I start getting hot I turn on the House AC as a supplement to the dash AC - until I can find someone that can fix it right.