Dash Vent/Heat/Air

[fulltiming]

Today, Tom and I spent the afternoon tracking down a problem I have had for the 3 years I have owned my coach, i.e. virtually no air comes out of the dash vents or defrosters.

We determined that the air flow was not significantly improved by opening up the rear of the blower chamber (eliminating the air intake as being the cause), that the air flow coming out of the top of the air plenum was indeed pitiful (eliminating the ducts as being the cause), and that the amperage draw was appropriate. That left excessive voltage drop as a potential cause. We hookup up a battery charger to the power supply line and got no improvement at 13+ volts. We then tried reversing the direction of rotation by swapping the positive and negative leads on the motors. That did it. All three blower motors had been wired (or rewired at some point) incorrectly and the squirrel cage blowers were turning the wrong direction.

After rewiring all three motors, I now have significantly better air flow than anytime I have had the coach. The airflow is equal to or great than Tom's Newell.

Thanks for the help Tom!!

[chockwald]

Congrats, Michael! It helps to have two brains troubleshooting problems like that!

[Richard and Rhonda]

Cool, I mean Hot.

Any way. This is a great site for heater and AC info for coaches. http://www.evanstempcon.com/guides_scs.php

[encantotom]

in looking at the site richard posted, it shows a convention for the wire colors that must be standard. it shows the blower motor as black and orange wires. black to ground and orange to hot. that is the colors on mine and michael's blower motors as well. i thought it was strange when the black wires were the hots and the orange ones were grounded.

the real mystery is how in the world or why in the world did someone change the wiring to be backwards. it had to have worked when new. it was obvious that it was connected correctly at some point because the black wire had an inline splice on it with the wires clipped off and the splice taped. that would have only been to connect all the ground wires together.

when we re-wired michaels, we gave it a better ground as well. a direct ground versus grounded to the blower motors themselves.

anyway, it works great or as great as they get. it is not as strong as my car, but not far off.

later

tom

[tuga]

I had a 1987 & 1993 Newell and neither one of them had cold dash air. I was told many different reasons: 45' was too far for the freon to travel, change this part change that part - nothing worked.

Does anyone have this vintage Newell (1993~)that blows good cold air?

[fulltiming]

Tuga, the temperature of the air coming out of my vents is around 38-40 degrees. That is about all you can expect out of most AC units. The bigger problem I have seen is the lack of sufficient air flow. After rewiring my blowers, the quantity of air coming out of the vent doubled or tripled. That still doesn't compare with the air flow I get out of the AC vents on my PT Cruiser.

[Richard and Rhonda]

Tuga,

I get cold air at the vents, but not much of it. I have replaced the compressor, refurbished the expansion valve, and keep the gas level at the max charge. However, like most of you, the air flow is weak. My situation is not helped in that the mechanisms that direct air to the different vents based on the button selection do not work very well. So, my air tends to come out of all the vents all the time.

[zcasa]

We gave up on the dash air on our 1992. We simply disconnected it and use the generator when necessary. Probably costs a little bit more on diesel, maintenance on the generator etc., but hey, we are cool when we need it. Since we don't park where we need the generator, it probably helps us to run it and use it this way on the road. Our coach is black, so the dash air was worthless.

[encantotom]

so,

i have replaced the compressor, dryer etc. i replaced the vacuum pump and valves at the dash.

i also fixed the various leaks in the ductwork and have pretty strong air flow and quite cold air now.

tom

[chockwald]

I was lucky...when I got my coach it had plenty of air volume, but was not cold. Had to replace the enormous belt driven compressor, and the dryer....now it makes my knees numb....LOL!

[Richard and Rhonda]

Clarke,

I had a brain fade yesterday when I heard you describe your loss of air flow with the AC problem. I don't think it's your fan. I think your gas level is low. The first clue is the previous post. When the pressure is low in a refrigeration system you get very low cooling temperatures. Those low temps cause the water in the air to actually freeze on the evaporator unit that the fan blows across. When enough water freezes the air stops going through. Put some gauges on the compressor and have the pressure checked. When the low side pressure gets really low, a switch will keep the compressor from coming on, but before that happens you will blow ice cold air, for a little while.

I feel like a dummy cause I had gauges and 134a in the coach with me. Doesn't really help that the answer came to me when I was almost back to Fort Worth. Sorry.

[chockwald]

Wow....that makes so much sense to me, because I can hear the fan is on, but no air is coming out, so the evaporator must be freezing up...that's why it works again after being stopped for a couple of hours....brilliant! I'm going to check to see if I can find a mobile service to come out and check it out. I just had the freon topped off, so I must have a leak somewhere....UGH!

And, thanks again for your presentation last night....it was invaluable, and I will use the information to get my mom "off the dime" and "get 'er done".

[Richard and Rhonda]

I know it's too little, too late, but if you want to swing up through FTW on your way home, I have a leak sniffer, guages, and a jug of 134. Let me know.

Tom has my cell #

[chockwald]

The problem is that the condenser is freezing up (you where right), but what is causing it is that the evaporater, and condenser are never cylcing on and off....they are always on, and this is being caused, we believe, by a faulty temperature control rheostat. The one in my coach has two wires, plus a thermocoupler which goes to the condenser. Even in the "off" position it is still on. Trying to locate this ancient rheostat right now. Below is a picture of my primitive A/C controls....2 knobs...one for A/C temp, and one for A/C fan....will keep you posted.

[chockwald]

OK, here is where we are.....we installed a cutoff switch using the ground wire off the evaporator to manually turn it off, so it isn't running continuously. Michael mounted the switch just above the gear shift for easy access...it's only mounted temporarily until we figure out why the evaporator will not cylce off and on as it should. Now if, and when the condenser freezes up I can turn off the fan, and the evaporator fan and let it thaw out, and then turn it back on. We checked the freon and the pressures are right where they should be, so we've ruled out that as causing the freezing problem. Thanks to Michael Day and Tom McCloud for spending 3 hours on my problem...Tom only charged $275/hour plus $15 per fitting.....just kidding. Thank you Richard for steering us in the right direction! These guys are really a blessing. I think they have helped solve a myriad of problems the last 5 days! Tom and I are heading west on I-10 tomorrow morning and hope to be in Mesa by Saturday.

[Richard and Rhonda]

That'll work. May I suggest that you turn off the compressor periodically before you begin to lose air flow, and leave the fan running. That will mimic what actually happens in a properly functioning system. You will know when to turn the compressor back on when the air coming out of the vents starts to get warm.

And I'm torqued. Tom charged me 350 an hour.

[chockwald]

We're in Ft. Stockton, TX this evening. The manually controlled switch for the compressor/evaporator worked great. When I noticed airflow beginning to dimish I turned it off for about 15 minutes, and the air flow returned quickly. The rest of the day it was much warmer, and I didn't have to turn it off, but I will take your advice and periodically just "cycle" it off for a few minutes. Had great A/C all day!

I feel so special about my "low" hourly rate....LOL!

[hlfdzn]

I've read through the above posts and referred to the links (thank you Richard!), but haven't been able to resolve the complete lack of air. There is 12v going down to the blowers and it switches on and off when the heat/defog buttons are pushed, but the motors aren't moving. I'm sure there is something easy I'm missing... How could all of the blowers go bad?

I have three blowers (not sure if that is standard), does anyone know what each blower goes to? (i.e. heat, defog, ac, etc)

One interesting thing, all my blowers are wired similarly as Michaels. The orange wires are to ground and the black wire is to the orange wires from the coach. Once I get them running, I'm going to experiment with swapping the wires to see if there is any difference.

After this is fixed, a previous related issue that needed fixing was the heat/defog had minimal or no heat. Tom mentioned that there is a pump for coolant, where is that located?

Thanks,

[folivier]

I have the same problem with only warm air coming out of the dash heater vents. I went a different way. I ran a heavy extension cord from the plug-in for the overhead tv (which is off of the inverter) down to the center console. I plan to use a small electric heater around 750-800 watts worth to warm up the front seats. If the coach is warm to start the small heater should keep us warm all day.

[encantotom]

i pm'd you my cell phone number

tom