A/C Temperature

[kennpriebe]

Hey there.

Can anyone tell me what the temperature should be, coming out of the ven with the A/C on. What temperature should I expect when going down the road with full A/C and temperature outside is say 90 degrees or when it is say 70 degrees?

I had a retrtofit done on a 91 bounder and after all the problems were worked out I am getting in the low 50's when the outside is about 85 to 90. Is that considered adequate or should I expect better performance?

Thanks for any information you can provide. I have a temperature guage stuck in the middle output vent on the dash. Oh, by the way it is a 1991, bounder, 460 ford engine. 28foot model.

[Flagelpater]

I am not an expert on A/C systems, but, I was told a 30 degree drop is expected from the input temp. Not outside air temp, input temp. This would be down to a set minimum Temp to prevent freezing. Hope this helps until an expert chimes in.

[Gary RVRoamer]

A 30 degree drop from the input air is fabulous. 20-25 is more typical.

Are you talking about the dashboard a/c or the house a/c? The house a/c is always recirculating inside air. The dash a/c may be recirculating (sometimes called Max Cooling) or may be trying to chill outside air that comes in via the dash vent system. On very hot days, the dash a/c will likely chill the outside air only 20-25 degrees, so it is best to use the Max or RECIRC position on the control. That will allow it to gradually reduce the inside temperature as the interior cools off.

[mick]

Actually MOST a.c men will tell you that a 20 degree difference is the thing they shoot for. Some get more , some get less, depending on the effecency of the a/c. Personally I get 26 degrees seperation.

[Flagelpater]

My unit does not have a Recirculate selection for the Dash Air. I need to select MAX AIR to get it into a recirculation mode. On hot days I use the GenSet and the roof A/C units because the Dash inlet air temp is always too high due to the cabin volume. Thank you for correcting the 30 degree statement.

[kennpriebe]

I am talking about the dash air. I have had some intermittent problems that I hope are now worked out, due to my 1250$ outlay for retrofit and then some parts replacement and numerous evacuations and refills.

I think on the way home from the shop I was able to get mid 50 degree air when the outside airt temp was probably 85 to 90. So, from what I hear I guess that is all I can expect. Seems like these systems are not as cold as in a car.

Thanks for taking time to respond.

Kenn

[Gary RVRoamer]

Air temp coming out of the vents should be abut the same as a car, but the interior space is greater so the cooling effect is less.

[dieselclacker]

Kenn, if you are measuring the mid fifties temperature at the discharge duct in the dash, then something is wrong with your system. Low forties or even high thirties are more the norm. Stick a thermometer in the outlet of the A/C duct of your car, your motorhome is capable of the same temperature, (same system). As Gary says, the volume inside your motorhome is much greater, so the overall inside temp will not be as low as your car, but the discharge temp sure should be. The A/C outlet temp on my 8.1 Allegro runs consistantly in the low forties, but on a very hot day, it cannot keep the temperature to a comfortable level within the motorhome.

Dieselclacker

[justimagination]

Quote:

Originally Posted by dieselclacker Kenn, if you are measuring the mid fifties temperature at the discharge duct in the dash, then something is wrong with your system. Low forties or even high thirties are more the norm. Stick a thermometer in the outlet of the A/C duct of your car, your motorhome is capable of the same temperature, (same system). As Gary says, the volume inside your motorhome is much greater, so the overall inside temp will not be as low as your car, but the discharge temp sure should be. The A/C outlet temp on my 8.1 Allegro runs consistantly in the low forties, but on a very hot day, it cannot keep the temperature to a comfortable level within the motorhome. Dieselclacker

Kenn, he's telling you the way it is. Typically on a good charged system, outlet temperature can and should run between 38-42 degrees. You will find the system will work better if you will use the recirculating rather than vent, slide your temperature lever to the coldest setting, and drop the fan speed to about the middle speed, this gives the evaporator more time to CHILL, thus giving you cooler outlet temperarures. Your dealing with a much larger windshield, and a whole lot more heat than a passenger car. Give it a try, it works for me, JMHO.... Good Luck.
David G.

[kennpriebe]

It does look like there are still problems with the thing. I am only getting to about 52 or 53 with the temperature in the vent on the dash. The service guys are stumped. They have 90 years of experience with these systems and have spent many hours with this thing, replacing several parts. Not really sure what to do at this point. They couldn't find a replacement dryer part (I think) so that is being reused.

I may have to live with the problem.

Kenn

[kennpriebe]

Others commenting on this strand, have said that the outlet temp at the vent should be 38 to 42. Are you in agreement with that or is that too optomistic for this old system, retrofitted with r 134?

Kenn

[wa8yxm]

If you download the Maintenance Manual for your air conditioner then in the manual there will be a chart..

To properly test you need what GM calls a 3-terminal thermometer as I recall.. Really it's 4 thermometers

You measure the inlet temp on the condensor (outside or hot coils)
That is the air entering the coils.. The outlet temp (Air that has passed through)

You do the same for the evaporator,, Both warm air entering and cold air leaving

Then there are some charts

I look for a 30 degree drop, however 20is, as I recall, acceptable.

So if it's 90, IN THE ROOM and the air comes out 70.. You are good.