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Luckysnuck · 06-27-2019, 10:39 AM

Curious if others have experienced this?

Last week on a 6 day out & back trip to SC from my OH home base twice in my 2018 AIGT the chassis (not overhead house) AC behaved strangely. I'd be running @ interstate speeds, AC on, thermostat set @ 68~70 or lower, fan set at 2~3 clicks and then suddenly the velocity of the air flow would diminish and the air flow temperature from the vents transitioned from typical AC chilled air to just mediocre cool air. I found that if I depressed the AC button to off for a while (20~30 minutes) and then depress the AC button back on, then the AC would behave as normal to the specified air flow velocity with customary chilled AC air. Outside ambient temperatures were high (85~90F) when this occurred so I'm uncertain if this was a contributing factor.

Any input/comments would much appreciated.

Thanks Friends!

wachuko · 06-27-2019, 11:19 AM

What is the dial that controls airflow set to? We had a similar issue in one of the trips and it was due to me moving that dial without knowing what the heck i was doing.

I still do not know what the heck I am doing, but now I do not touch that dial...

toskeysam · 06-27-2019, 12:12 PM

This is not uncommon problem. The coil iced over if conditions are right. I battled this on a Florida trip. I had to strike a happy medium of 70 degrees when there is extreme humidity. When you shut the compressor off you let the warm air melt the iced-up coil and you can resume normal AC conditions. Royal PIA but nothing catastrophic.

Luckysnuck · 06-27-2019, 12:25 PM

Quote:

Originally Posted by wachuko

What is the dial that controls airflow set to? We had a similar issue in one of the trips and it was due to me moving that dial without knowing what the heck i was doing.

I still do not know what the heck I am doing, but now I do not touch that dial...

My airflow direction dial was around 8:00~9:00 o'clock.

Luckysnuck · 06-27-2019, 12:28 PM

Quote:

Originally Posted by toskeysam

This is not uncommon problem. The coil iced over if conditions are right. I battled this on a Florida trip. I had to strike a happy medium of 70 degrees when there is extreme humidity. When you shut the compressor off you let the warm air melt the iced-up coil and you can resume normal AC conditions. Royal PIA but nothing catastrophic.

This makes sense for a few droplets of moisture did blow out of the vents a short while after clicking the AC button to off.

Thanks for your insight.

wachuko · 06-27-2019, 01:52 PM

Quote:

Originally Posted by Luckysnuck

My airflow direction dial was around 8:00~9:00 o'clock.

I will check where mine is set at because, after moving it to that spot, I have not had an issue with the A/C...

Pahaska · 06-27-2019, 01:59 PM

Freeze-up. I have had this happen in both my 2014.5 AI and my 2018 AI. When you turn the AC off, you get some cooling as long as the ice lasts. First time it happened was on a fairly mild, but humid, October day crossing Missouri with 2 bars of fan on.

After having it occur in both rigs, I suspect it is something that I will just learn to live with.

Alex AVI · 06-27-2019, 06:52 PM

Quote:

Originally Posted by toskeysam

This is not uncommon problem. The coil iced over if conditions are right. I battled this on a Florida trip. I had to strike a happy medium of 70 degrees when there is extreme humidity. When you shut the compressor off you let the warm air melt the iced-up coil and you can resume normal AC conditions. Royal PIA but nothing catastrophic.

Quote:

Originally Posted by Luckysnuck

My airflow direction dial was around 8:00~9:00 o'clock.

Quote:

Originally Posted by Pahaska

Freeze-up. I have had this happen in both my 2014.5 AI and my 2018 AI. When you turn the AC off, you get some cooling as long as the ice lasts. First time it happened was on a fairly mild, but humid, October day crossing Missouri with 2 bars of fan on.

After having it occur in both rigs, I suspect it is something that I will just learn to live with.

LUCKYSNUCK - Sorry to hear. Agree with everything TOSKEYSAM, WACHUKO, & JOHN (PAHASKA) said. I stay 69-70 and as noisy as it is, use high volume 3-4 bars to get as much air going through the coils, and I stay away from outside air & keep putting it in RECIRC in high humidity.

Few reasons why:
1. High humidity can soak the cabin filter to the point of reducing airflow significantly. RECIRC bypasses that filter.

2. The MB system, especially brand spankin new is charged up to it's max, so if you put it to its lowest 58 degree setting, it can easily ice-up the evap, coz it is capable of going that low. As unit gets older and you lose a teeny bit of refrigerant (yes, I know it's a sealed system and not supposed to lose refrigerant but it does settle in to its long term level, according to my HVAC tech friend), it still gets cold but not too cold for its own good.

3. Getting as much volume of air through helps "de-ice" the evap, much like a home ref does to prevent icing & keep temps in entire box consistent.

Happened to us while in SoCal few weeks after I picked up rv. Came from single digit Vegas humidity to 80% humidity near beach cities & forcing the issue, i.e. I had mine cranked to lowest temp (58 or 60, yeah stupid move). I started to get worried, then remembered some posts. Raised my temp dial to turn off compressor and turn fan to 4 bard. Literally came back in less than 5 mins. Most stressful 5 mins of my newbie rv life

c21 · 06-27-2019, 08:11 PM

Ditto on what Toskeysam said. I've had mine freeze up on a couple of occasions after extended run time. Turn off the air for a few minutes and you'll be good to go. If it's too hot, fire up the generator and run the roof air for a while.

JohnandJan · 06-28-2019, 10:56 AM

Another issue might be the cabin ventilation filter, which is in the engine compartment, getting clogged. We live in NM and this happens frequently enough that we carry a spare on our trips.

Luckysnuck · 06-28-2019, 09:12 PM

Quote:

Originally Posted by Pahaska

Freeze-up. I have had this happen in both my 2014.5 AI and my 2018 AI. When you turn the AC off, you get some cooling as long as the ice lasts. First time it happened was on a fairly mild, but humid, October day crossing Missouri with 2 bars of fan on.

After having it occur in both rigs, I suspect it is something that I will just learn to live with.

Thanks very much for sharing, understanding the details of your experience with this helps immensely.
Happy Trails🚐

Luckysnuck · 06-28-2019, 09:27 PM

Quote:

Originally Posted by Alex AVI

LUCKYSNUCK - Sorry to hear. Agree with everything TOSKEYSAM, WACHUKO, & JOHN (PAHASKA) said. I stay 69-70 and as noisy as it is, use high volume 3-4 bars to get as much air going through the coils, and I stay away from outside air & keep putting it in RECIRC in high humidity.

Few reasons why:
1. High humidity can soak the cabin filter to the point of reducing airflow significantly. RECIRC bypasses that filter.

2. The MB system, especially brand spankin new is charged up to it's max, so if you put it to its lowest 58 degree setting, it can easily ice-up the evap, coz it is capable of going that low. As unit gets older and you lose a teeny bit of refrigerant (yes, I know it's a sealed system and not supposed to lose refrigerant but it does settle in to its long term level, according to my HVAC tech friend), it still gets cold but not too cold for its own good.

3. Getting as much volume of air through helps "de-ice" the evap, much like a home ref does to prevent icing & keep temps in entire box consistent.

Happened to us while in SoCal few weeks after I picked up rv. Came from single digit Vegas humidity to 80% humidity near beach cities & forcing the issue, i.e. I had mine cranked to lowest temp (58 or 60, yeah stupid move). I started to get worried, then remembered some posts. Raised my temp dial to turn off compressor and turn fan to 4 bard. Literally came back in less than 5 mins. Most stressful 5 mins of my newbie rv life

Alex,
Appreciate you chiming in, your comments with regard to utilizing the RECIRC more often in high humidity scenarios like I was experiencing was an excellent reminder of the utility that function provides; who knows, I may not have experienced any of this if I would have had that on (???).
As always appreciative of your and everyone’s knowledgeable guidance on these bumps in the road.

Luckysnuck · 06-28-2019, 09:42 PM

Quote:

Originally Posted by JohnandJan

Another issue might be the cabin ventilation filter, which is in the engine compartment, getting clogged. We live in NM and this happens frequently enough that we carry a spare on our trips.

Thanks John & Jan for your comment; it had not occurred to me to consider this as a possible root cause of this issue, but I’ll definitely check that filter to insure that it’s functionality is where it should be. I’d suspect that the locations of my travels since my AIGT Ext purchase last August (midwest, southeast & northeast) are generally speaking not as of a dusty environment as the west & southwest, but it’s definitely worth being mindful of, thank you!

Luckysnuck · 06-28-2019, 09:46 PM

Quote:

Originally Posted by c21bill

Ditto on what Toskeysam said. I've had mine freeze up on a couple of occasions after extended run time. Turn off the air for a few minutes and you'll be good to go. If it's too hot, fire up the generator and run the roof air for a while.

Good suggestion Bill, thanks for your input, us newbies (me) value your veteran knowledge👍

nuttinbutxs · 06-29-2019, 07:39 AM

Probably not the issue here but thought I'd mention it. I had a GMC truck a few years ago that would shut down the AC if you were climbing a steep hill or were straining the engine and needed the extra power. It would go back to normal once you cleared the hill or whatever it was that you needed the extra power for. Don't know how the AI is set up but was just a thought.

Pahaska · 06-29-2019, 08:44 AM

Quote:

Originally Posted by nuttinbutxs

Probably not the issue here but thought I'd mention it. I had a GMC truck a few years ago that would shut down the AC if you were climbing a steep hill or were straining the engine and needed the extra power. It would go back to normal once you cleared the hill or whatever it was that you needed the extra power for. Don't know how the AI is set up but was just a thought.

Not the problem with Sprinters. My ice-ups were always on fairly level terrain at constant speeds. The ice-up I mentioned above was near Joplin, going west on I-44 in Missouri, at a steady 65 mph. Other ice-ups happened in southeast Texas in high humidity and flat ground.

I leave the fan running and turn off the AC. In a minute or two, I start to get some colder air from the melting ice. It will get quite cold for a time, then start to warm up. I give it a couple more minutes to dry out, then turn on the AC again. I have never had it ice up again on the same trip.

Alex AVI · 06-29-2019, 02:54 PM

Quote:

Originally Posted by nuttinbutxs

Probably not the issue here but thought I'd mention it. I had a GMC truck a few years ago that would shut down the AC if you were climbing a steep hill or were straining the engine and needed the extra power. It would go back to normal once you cleared the hill or whatever it was that you needed the extra power for. Don't know how the AI is set up but was just a thought.

NUTTINBUTXS - Yeah, that happens too. AFAIK, every vehicle I have owned has done that to certain extent when demanding max power/load but my experience with my Sprinter is that particular issue does not happen too often. And the OP situarion is a complete different thing.

wachuko · 06-30-2019, 08:17 AM

Forgot to share the photo... again, this has worked for us. And since that time on our trip from Missouri, we have never move it from that setting and have not had any reoccurrence...

Luckysnuck · 06-30-2019, 04:48 PM

Wachuko,
I am going to try your suggestion on this "3:00 o'clock setting" on the airflow. It seems as thought I've tried multiple settings around the entire dial with various degrees of success and/or failure. If as you've commented leaving it at this spot has been "good", then that's good enough for me, plus I'm tired of experimenting...I'll share my experience "down the road" as they say...
Thanks!

AlbertF · 07-03-2019, 10:21 PM

Icing on humid conditions is a very real possibility. However, if the problem persists despite your efforts to manage it, the AC clutch may be the culprit. They can wear and the gap becomes too great for the electromagnet to keep the clutch engaged. This problem is always worse in hotter weather.

The solution is a new compressor or re-shimming the clutch to reduce the gap. A shop will do the former; the latter is a DIY job due to the time required.