Dash Air Conditioning

[joeandtricia]

Looking for feedback/knowledge from folks...what should our expectations be about the Dash A/C in our motorhome? We have a Georgetown Class A that is on the Ford V10 chassis. It has a dash A/C, which blows cold air (if you put your hand right in front of the vents) but you don't really feel it being cold when it blows on you.

I had our dealer check it out, and they said it's blowing fine...but that in a motorhome like ours the dash A/C really isn't supposed to be useful. You're supposed to rely on the big A/C units on the roof. Well, that means that we always have to have the generator running when driving.

Is this true? Or should I be arguing with the dealer that the dash A/C just isn't right?

[dezolen]

Our dash air keeps us frosty in 90 degree weather while driving our 2013 Allegro with Ford chassis. See absolutely no need to run generator for coach air unit

[senior-cit]

Had problems with the dash air on our Winnebago 2011 Adventurer and had the compressor replaced because the seals were bad we were told. it was under warranty so no cost to us. However, the air still continued to blow warm air. Went back to Ford truck dealer and they found a hose had been rubbing against something under or on the chassis. This hose was not warranted so had to pay for repairs. That did, however, solve the problem and air is cold. The dealer told us that because the hose wasn't a ford installed part, they couldn't cover it. Has anyone else had this same problem with that or any hose rupture do to rubbing against the chassis?

[RLS7201]

dougrainer wrote:

Groover wrote:
Automotive air conditioners use a cool-reheat system where the air is cooled by the air conditioner and then warmed to a comfortable temp if full cooling is not required. It can even be heated to an elevated temp for de-fogging the windshield. If the reheat function is not shutting off properly it can make your airconditioner useless. Turn your system to "Vent" and the temp all the way down and see if the output air is warmer than the air coming in. If so, you have a heater control problem. Some Fords have a valve in the hot water line supplying the heater that is supposed to shut when no heat is asked for. If that valve leaks your air will be warmed somewhat, how much depends on the leak rate. My father had a Ranger with that problem new. The dealer's mechanics had no clue how the system worked or what that valve did. He finally replaced the valve himself and solved the same symptons that you are describing.

Good Luck.

ALL CORRECT. BUT, NOT for RV motorhome systems. Motorhome systems have no such blend door system like Automotive systems. Yes, if the Hot water shut off is seeping or not closing, the AC will not cool but when that happens on a motorhome system, the air output will be over 100 degrees and higher. Doug

Doug,

The Denso AC/heater systems used by Fleetwood in the 90s and early 2000s is indeed a blend door system. No water control valve used. I have personally been inside said systems, replacing exp. valves and heater cores.
It is a much more robust system than used in small truck cabs.

Richard
95 Bounder

[Mr_Mark1]

rgatijnet1 wrote:
If the air coming out of your dash Ac ducts is not cool enough, the first thing I would check is whether or not you have a leaky heater control valve. If even a slight amount of coolant leaks past that valve it will cause the heater coils to get hot and raise the temperature of the air blowing into the coach. The adjustable heater valves are known for leaking so you may want to just add a cut-off valve in the syetem to stop water circulation during the months when you need AC.

That's a good point, to have a cut-off valve put on for the heater. I never use heat, never (while driving). I like it cold, ice cold, blowing right in my face.

Off topic, but my Dad inherited his brother's '02 Chevy Impala. I cannot believe how ice-freezing-cold that car dash air is. I've had many cars with perfectly great working air conditioners but I have never seen one as cold as this car and it's an 11 yr. old. I have had to turn it down when it's was almost 100 degrees outside with 90+ humidity.

MM.

[rgatijnet1]

If the air coming out of your dash Ac ducts is not cool enough, the first thing I would check is whether or not you have a leaky heater control valve. If even a slight amount of coolant leaks past that valve it will cause the heater coils to get hot and raise the temperature of the air blowing into the coach. The adjustable heater valves are known for leaking so you may want to just add a cut-off valve in the syetem to stop water circulation during the months when you need AC.

[Tyge]

Don't know if U can , But I put a rod across behind Driver and Pass Seats and put a shower Curtain on it to contain the A/C air !

Worked For Me / Tyge

[JC2]

We have always run our dash air in the MaxAir position(no outside air is pulled in) 99% of the time, and occasionaly use our overhead dash fans on low to help move the air around. This keeps the front of the coach very comfortable back about 6-8 ft when outside temps are in the mid/upper 80's or cooler. After that, we start the gennie when outside temps start rising and turn on the front overhead coach air to supplement and set it's fan on high. On rare occasions, we have run the second coach air when in places like Az, NM, NV. Our vent temp exiting the dash air will remain in the 42-47 degree range regardless of how hot the out side temp is. Bottom line, keep the dash air on the MaxAir position, use the overhead fans on low if present, use the gennie and roof air(s) when needed. They're meant to be used and should not be sitting idle.

[chuckftboy]

topflite51 wrote:
It is my understanding that the dash air in the MH was never intended to cool the entire coach while traveling. It is intended for the driver and front passenger. If it is working properly it should blow approximately 50degs when the ambient temperature is 70. On my F53 I set the fan to high, the temp to its lowest setting and press the recirc and vent buttons. I have driven considerable miles with the outside ambient temperatures are in excess of 100 degrees and I have yet to be uncomfortable, heck my wife even closes one of the vents blowing on her as she feels it is too cold. I have never ran the coach AC's while driving. I would not hesitate to do so if I were the least bit uncomfortable.

Same for me, very seldom do I use the roof a/c I do run it on occasion when in the high 90's but my dash air seams to do just fine. Maybe Fleetwood just does a good job of insulating.

[topflite51]

It is my understanding that the dash air in the MH was never intended to cool the entire coach while traveling. It is intended for the driver and front passenger. If it is working properly it should blow approximately 50degs when the ambient temperature is 70. On my F53 I set the fan to high, the temp to its lowest setting and press the recirc and vent buttons. I have driven considerable miles with the outside ambient temperatures are in excess of 100 degrees and I have yet to be uncomfortable, heck my wife even closes one of the vents blowing on her as she feels it is too cold. I have never ran the coach AC's while driving. I would not hesitate to do so if I were the least bit uncomfortable.

[Ivylog]

I'm pretty sure the air hitting the doghouse from a V10 with the AC on is hotter than the air hitting the rear bedroom of a DP.
I rarely have to run my roof air, but there is only two of us and I close the door to the back and leave a roof vent open back there.
As was suggester earlier, you need to make sure the hot water is turned off to the heater and most DO NOT shut all the way off so I added a manual valve to mine. I also removed the cap tube from the evaporator so my compressor never turns off, but in the East after 4-5 hours the air flow will drop off because the evaporator is stating to ice over. Turning the AC off and running the fan on high for 15 minutes will usually melt the ice and your good to go for another 4-5 hours. Out West it rarely ices up because of the lower humidity. These changes let me run only the dash AC on days when it's 100. I do leave two of my AC's turned on so 20 minutes before getting to a CG on a hot day, I start the generator to cool the back of the MH down. If it gets too hot while traveling all I have to do is reach down and start the genny.
I also adjust the amount of freon in my system by making sure 90% of the condenser is 15-20 degrees hotter than the last 10%.

[joeandtricia]

Not too long after posting this question, our motorhome broke down (compressor seized and broke the serpentine belt). They had to replace the compressor and the belt. Now, we have MUCH better A/C in the cab then we ever had before. While the old one was "in spec" in terms of temperature of the air it put out, the new one is way better.

[wny_pat1]

I have read many times on this very same forum that if one wants to stay cool while traveling down the highway in a very warm state like Arizona, where the op is from, that one has to run the over head air. To me, when the outside air is 100 degrees and the inside air is 75 or 80 degrees, that is still hot!!! Most motorhomes are not well known for their insulation quality. No matter how much cold air your AC blows, there are a lot of cubic feet that it is trying to cool down, and mother natures is doing everything she can to prevent it!

[sc3283]

Remember when comparing AC performance here on the net...what is cold to me might not be cold to you...so me saying mine works great, while you say yours doesn't is useless...without a true vent temp reading any comparison is useless.

I always froze the wife out in any vehicle we had when using the AC....then we grew older...and she then became too warm even though I was freezing...not being rude....just showing my point of comfortable being a variable.

[Mr_Mark1]

phnguyk wrote:

dougrainer wrote:

Mr.Mark wrote:
I might be mistaken but A/C is A/C whether it's in a class A diesel or gas unit, right? We can run the dash A/C up to about 95 degrees outside. After a prolong period of that temp, the rear starts to warm up from the engine heat.

Anything over that temp I'll crank up the genny and run all three air conditioners. It's nice to arrive at our destination with the interior cooled off on a hot day.

MM.

Yes, you are mistaken. Rear Engine Diesel will get colder than a Gas engine front. The reason is the gas engine heat of the forward compartment and the fact that the Condenser FOR the AC is installed in front of the Gas Engine Radiator and Gas engines run hotter than Diesels. Also, the Condenser for most Diesel's are separate from the radiator and even if part of the radiator, the Diesel runs cooler and the ability for a Condenser to remove the heat from the AC coolant and the better it does that is a big factor in how cold a Dash AC will get. Doug

That's the craziest thing I've read in a while. Diesels run hotter, that's just how they run. My v10 never goes over 170, I'm sure your diesel is running hotter than that. The only reason your diesel gets colder has to do with the physical size of the components.

OP, you should see anywhere from 55-65 degrees right at the vent regardless of exterior temperature, put a thermometer in a vent. Any higher and there's a problem, freon, leak but something. Common problem on the f53 is the heater hose valve not shutting completely, google it, replace with a manual valve shut it in summer open it in winter.

One way to troubleshoot it is, does your fan speed change when switching from a/c to max a/c?

Doug, you are the mechanic, I am not. But, my radiator temp runs about 197-199 and the transmission 205-207 on a normal day. I know that my air conditioning components are separate but a diesel runs pretty hot when rolling down the road. When at idle, they will cool down really good.

It sounds like our components are the same but just located in different spots.

So, I'm half right, right? LOL!
MM.