Dash Air

Just purchased a 1995 Winnebago with 53000 miles on it.  The dash air does not work.  Is it worth the expense to repair,  or just use the gen set?  Dealer says leave it be.
Thanks  Mr Dart

MrDart said:

Just purchased a 1995 Winnebago with 53000 miles on it.  The dash air does not work.  Is it worth the expense to repair,  or just use the gen set?  Dealer says leave it be.
Thanks  Mr Dart

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Mr Dart
What do you mean the dash air not work ? Is it the fan, compressor.
Pat

our compressor bit the dust over the past year.  Given the cost benefit we decided not to try to get it fixed.  To be honest, any time we have really needed air, we have had to start the generator and run the coach's air to get any real cooling.

What kind of chassis do you have? 

In the summer, we run our dash air until we stop for lunch, then it's genny time.  Personally I would miss our dash air, but you have to look at the cost-benefit ratio.  I'm not sure I would miss our dash air if it cost a kilobuck to fix.

Yep...we need more info to reply intelligently. 

If it is a Workhorse, it will blow warm air when stopped....plain and simple, due to the low air movement across the Evaporator.  When you get moving, it will cool down.

If the fan blows but the air is warm, it may not be the expensive compressor component. I had one where the valve that controlled hot water inlet to the HVAC system was stuck part way open, thus supplying heat even when the a/c was on. In another, the vacuum-operated valve that sent the air flow over the cooling unit failed and my a/c was working but the air didn't cool. Those were $200-$300 fixes, mostly labor. I's pay $250 to have the dash air, but not $1000.

Like John, we use dash air in the morning but switch to genset & house air when the day heats up in the afternoon.

Well, this is a very simplified explanation of how Air Conditioning works and possible problems

A pump, called a compressor, compresses a gas This makes it very hot, it is then pumped through a heat exchanger (Called a Condenser) where it cools enough to turn into liquid, this liquid is under great pressure and is then pumped through a special valve into the Evaporator (Another heat exchanger) since it lost so much heat when it was in the condenser as it's sprayed into the very low pressure enviorment of the evaporator it gets very cold, so it absorbs heat

In most air conditioners the cold air coming out of the Evaporator is then either mixed with heated air from the heater, or heated by the heater to the desired temp (Kind of strange I do admit, but that's how they do it)

Possible problems:

Bad compressor, bad compressor clutch wire problem blown fuse, prevent compressor from working

Low coolant (R-134A in a rig of your age I think, but do check it) means it can not compress it hot enough

Clogged lines (it happens)

Bad Expansion Control Valve (Happened to me)

Bad mixing gate or hot water flow control valve means you get all hot air  (Happened to many)

That last one is fairly low-cost to fix.

Some of this can be easily "Diagnosed'  For example if you can locate the compressor you can visually verify the operation of the clutch, this also verifies all the wiring and fuses and such,  Or even if you can't see it you may be able to HEAR it engage

However some of it requires special tools or professional assistance.. That expansion valve for example.  That took two experts, The first one I knew was nuts (He diagnosed a low pressure cut off switch, had that been the issue the compressor would not have engaged)

Wow, great explanation John!  I learned something, and mine works fine.  As far as the fix goes, if it were mine I would have to fix it.  I am wound pretty tight that way. If something has a system or feature, it HAS to work right.  Just my own weirdness,,,,,, :

Sarge

SargeW said:

Wow, great explanation John!  I learned something, and mine works fine.  As far as the fix goes, if it were mine I would have to fix it.  I am wound pretty tight that way. If something has a system or feature, it HAS to work right.  Just my own weirdness,,,,,, :

Sarge

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Wow!  I thought it was only me    I really hate when I have a piece of equipment and a feature doesn't work on it. 

If I bought it new it goes back, but if I got it 'pre-owned' I usually pull out my hair until I get it working again or prove to myself that I'd have to spend more than what I paid for it in the first place to get it working right.......even then I might fix it  :-[  I know, its a sickness.  :

My father on the other hand has the 'fix it just enough - it works', attitude, cultivated by growing up poor when fixing it properly might involve spending cash which he didn't have. 

We get into arguments with the camper I'm rebuilding if he can fix something 'good enough' but I still want to get the right part. 

OK, hear it is.  The fan for the heat works fine.  The same fan switch for the air does not blow at all.  The air feels cool at the vent but there is not enough air movement to force it out.  The fan will not operate the AC on any speed setting.  You can not hear the clutch engage or kick out.  The chassis is GM.
I will not take possession until next Fri the 6th, so it is difficult to tell if there is a separate fuse for the AC., or if the clutch is engaging. Assuming the worst, is it worth spending money on something that is not likely to cool the front section of the unit?
The overall length is just 25 feet.
Thanks for all the replies.

Ok...a 1995 P-30 Chassis.

If it was mine, I wouldn't fix it.....It wouldn't be able to cool your coach off anyway...its just good for the front passengers. 

Okay - Hmmm.. could be an electrical problem, bad pressures, bad clutch, ?? I think the prudent course of action is to get an AC tech to diagnose the problem, then you can make an informed decision about repairing.

MrDart.

  Sounds to me like that it may be simply a vacuum hose problem to one of the valves controlling the outlets. (Speaking from experience). My1995 Adventurer is 100% functional and has many years left, especially after I fixed the small hose problem.  ;D  Don't get discouraged, not everything is a major problem; just takes the right person to find the problem.

carson FL

Voyage1 said:

Ok...a 1995 P-30 Chassis.

If it was mine, I wouldn't fix it.....It wouldn't be able to cool your coach off anyway...its just good for the front passengers. 

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But If it was mine I would more then likely fix it, I may be tall to try  to steer for the couch it is a little tuff
Pat

Dash air is not intended to cool the whole rig anyway.  It is designed to cool the front seats, not the bedroom.  My dash air does just that.  It cools the DW and I going down the road.  If firing the generator an dropping your MPG 1/2 mile per gallon does not bother you, then by all means, go for it.  I base that on my 7500 watt Onan is rated to use .49 gph at half throttle.  And then you throw in that "gotta work right weirdness" and well, there you go........

In many cases it is just flat out more economical to start the Genset and use the roof air than it is to use the dash air.  In practice our 7.5 OD genset uses less than that.  The other advantage of running the the Genset is to excersize it which many cases gensets do not get run enough.

Thanks guys for all the input.  We will get an estimate, and make a call from there.
Many thanks.

The dash air in a 25 footer (Class C???) should easily cool the driver and passenger area while under way.  If it is  a Class C, it might be the only way to cool the driving area, since house air MAY not circulate all that well down into the cab area. Whether house air does or not reach the cab will depend on the specific layout on your coach, location of a/c vents, etc., so use your own judgement.

SargeW said:

Wow, great explanation John!  I learned something, and mine works fine.  As far as the fix goes, if it were mine I would have to fix it.  I am wound pretty tight that way. If something has a system or feature, it HAS to work right.  Just my own weirdness,,,,,, :

Sarge

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Nice to see someone else with this desease other than me ;D we run our dash air all the time, if it just wifey and I that is all that gets run. if the whole family is in there we run both the dash, and gen. The dash is easier to control the temp for me.