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?

[dpmotorhome]

my class a ford v10 dash air is blowing hot air, any ideas why?

[phnguyk]

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?

[lunch_surfer]

Heck my stick house AC can barley keeps my house cool during the summer here in Houston, so I figure 80 deg f when its 100 deg f ambient don't seem too bad in the bus. I think a lot of our trouble is wind intrusion from not so great sealing of the front ends. And as someone stated cubic foot of ac'd space is too large.

ctc

[sowego]

We found dash air in a motorhome is very inefficient in the large space especially when the heat soars. We will try to run open side windows by the driver and passenger and run the windshield fans but after a couple of hours of that...it is time to kick on the genny and run the roof AC units.

[Johno02]

Yes, it can, and does.

[Groover]

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

So how does the temperature control knob for the dash unit on my DP make the air warmer? If that mechanism mal-functions, could it not make the air warmer even when that is not desired?

[Dadio24]

2nd on many posts. The dash air is great when it 80F or below, above 80F, onan gets started.

[jimroach]

We too have a V10 Ford, and find the dash air pretty much worthless

[2112]

We were visiting a fellow camper in an A some time back and I noticed he installed semi-sheer curtains behind the cockpit seats. I said something about privacy, it being somewhat sheer and he replied it's for the AC. His dash AC works great with it and not at all without it.

It added an elegant touch to their coach as well.

[wa8yxm]

Here is an exercise for you.. If you have a FORD chassis, go find a Ford F-350 Custom Straight truck.. Take a look at the cab of that truck.

If you have an "Other than ford" Find a truck of simular size and type (Straight truck or Semi Tractor) and take a look at the cab.

THAT. is what the dash air is designed to cool.. That cab.

now, take a look at your big 30+ foot long class A.

No way on earth can it keep that big a house cool (Less of course it's Feburary and you are in Wisconson) but wait.. there's more.


Take a look at the amouont of windshield in your greenhouse v/s that straight truck.. Yup, it gets hot in the cab in Michigan in January due to the effects of the sun too.

[carp65]

In hot weather our dash air does not do the job even with a full curtain behind
the driver and passenger seat. Start the generator and run both or one A/C.
This works miracles!

[dougrainer]

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

[Groover]

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.

[dougrainer]

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

[-Gramps-]

With front engine...20 degrees cooler than outside is a reasonable expectation. With Rear engine expect it to be a bit more. My AC will turn my knees blue but doesn't do much for the top half of me due to placement of the vents. Plus I don't have any mounted dash fans. They make a huge difference I think.