Need Help With Dash A/C Problem .....

Topic: Need Help With Dash A/C Problem ..... (Read 3478 times) previous topic - next topic

Need Help With Dash A/C Problem .....

June 28, 2014, 08:34:12 pm

Dash Air was blowing warm .... Replaced: Dryer, High side hose from dryer to bottom of compressor, Low pressure switch, High pressure switch, Relay, 20 amp mini breaker under isolator.

Filled system with 7 (12oz cans) of R134

Now dash is blowing cold air, and Blower Motor works, but cycles when compressor does.

High Side Pressure is 150
Low Side Pressure kicks out at 25 and WILL NOT maintain 30-35 suction pressure.

How do I get level return pressure?

What kind of metering system is there, and WHERE is it located?

A friend has been doing all repairs, as I have NO knowledge in this area ...

I sure would appreciate all ideas of possible solutions to correct this situation. We are to travel from N. GA to Indiana next Tuesday ... Cold Dash air ... should would be nice!!!

Thanks All .....

Re: Need Help With Dash A/C Problem .....

Reply #1 – June 28, 2014, 08:41:03 pm

Sounds like you replaced most of system - expansion valve?

There are better experts here than me, but that is what was wrong with my 88.

Re: Need Help With Dash A/C Problem .....

Reply #2 – June 28, 2014, 08:47:02 pm

I think your system holds right around five pounds R134a. You may be overcharged. The expansion valve could need to be replaced. Mine was replaced two years ago.

Re: Need Help With Dash A/C Problem .....

Reply #3 – June 28, 2014, 09:03:33 pm

I own a 97 U295 40ft. Where is the expansion valve located?

?

Thanks for your help ....

Re: Need Help With Dash A/C Problem .....

Reply #4 – June 28, 2014, 09:16:02 pm

I can't help with the exact location but the TXV (expansion valve) will be located very close to the evaporator.

TOM

Re: Need Help With Dash A/C Problem .....

Reply #5 – June 29, 2014, 12:29:44 am

On mine, the TXV is up under the dash to the right of the air handler. It's wrapped in pipe insulation and somebody cut the wire ties and uncovered it. I'm not sure what they were doing.

Mine doesn't have a low pressure valve, but appears to have a low temperature sensor on the evaporator coils.

My low side pressures are staying around 20psi and I can see the TXV modulating it. My compressor will stay on most of the time when fan is on high, but cycles on slower speeds.

One thing that always should be checked is good airflow over the evap coils. Dirty air filter, dirty coils, broken ducts, etc will not let good heat transfer occur and the evap coils will get too cold and either lower pressure or cause the "Freeze switch" to cycle the unit.

Mine will blow nice cold 47deg air....and then cycle. It's almost too cold......I think I have to do some cleaning.

Anybody have information on the Dash A/C system or an instruction manual?

Re: Need Help With Dash A/C Problem .....

Reply #6 – June 29, 2014, 09:58:11 am

SNIP: On mine, the TXV is up under the dash to the right of the air handler. It's wrapped in pipe insulation and somebody cut the wire ties and uncovered it. I'm not sure what they were doing.

How are you accessing the TXV and the other dash-air hardware in the dash-area? I haven't discovered anything resembling easy access, but it appears you have?

Thanks!!

Re: Need Help With Dash A/C Problem .....

Reply #7 – June 29, 2014, 11:15:16 am

I can't speak for your coach, but a solid yank on the top of the "dog house" opens it up. It is hinged along the front side and used those brass spring ball cabinet door latch things to hold it down. Mine was pretty stuck!

I have to flip open the cover on the dash first, as it rests on the cover over top of the doghouse.

Re: Need Help With Dash A/C Problem .....

Reply #8 – June 29, 2014, 11:20:30 pm

We can see our dash air evaporator hose connections & valve bottom left of 12-volt breaker panel in front of co-pilot seat.

Re: Need Help With Dash A/C Problem .....

Reply #9 – June 29, 2014, 11:35:21 pm

Max freon is 80 oz's.

Good Luck, pc

Re: Need Help With Dash A/C Problem .....

Reply #10 – June 30, 2014, 10:45:52 am

Two relevant threads with info and pics:

Finally fixed my dash A/C

Dash A/C

Dash Air Intake

Re: Need Help With Dash A/C Problem .....

Reply #11 – June 30, 2014, 11:08:25 am

Also, to get pressures I liked, I put in around 6lbs of r134a. I still need to ensure my evap coils are clean.

Is there a manual or manufacturer information on these dash A/C units?

Re: Need Help With Dash A/C Problem .....

Reply #12 – June 30, 2014, 01:36:26 pm

Is there a manual or manufacturer information on these dash A/C units?

Yes, I second that notion, for the old (1993) unit.

Is the line going from front (evap)to rear ( compressor) a one piece line?

Re: Need Help With Dash A/C Problem .....

Reply #13 – June 30, 2014, 08:21:03 pm

If you are talking about the low pressure line the answer is yes, if talking about the high pressure line the answer is no as it goes from the compressor to the condenser and then from the condenser to the expansion valve. On the 93 the condenser is up front behind the grills

Re: Need Help With Dash A/C Problem .....

Reply #14 – July 05, 2014, 07:20:16 pm

I was looking at something else the other day and found the sticker with the manufacture info on the dash HVAC unit. "Specific Climate Systems" is the name. Google lead me to Victory Climate website and it appears they are still in business and have great parts catalogs with everything in them.

http://www.victoryclimatesystems.com/pdfs/rv/scs%20motor%20home%20units.pdf

Page 2 Model HC212 is listed as Foretravel 1994-1999.

The sticker on my system says HC212 on it.

Link to RV parts catalog: Victory Climate Systems- Climate Control Products for a World in Motion

Re: Need Help With Dash A/C Problem .....

Reply #15 – July 05, 2014, 08:45:48 pm

That's a great find Krush!
I see many familiar looking parts. It shows a unit for "Foretravel 1990-1992" but it doesn't match mine. Maybe it fits U225/U240 units?

Here's another resource with a good list of parts - scroll down to bottom to some handy .PDFs:
Motorhome Dash AC and Heat systems Note: I've never done business with them.
I think my '91 uses the "ACME Bubble Unit"
Seltec is the brand of A/C compressor on my coach. There's a PDF on Seltec compressors with a good visual guide to all the variations to help you find the right one.

1991 U225 airbox

Reply #16 – July 10, 2014, 09:25:41 am

Does anyone know how to get at the airbox to remove it for refurbishing? Doors don't move or seal or close. Burnt out vacuum pump already and can't find a new one of those either.

Re: Need Help With Dash A/C Problem .....

Reply #17 – July 10, 2014, 09:51:30 am

JDavid, You can use any vacuum pump as all it does is provide vacuum to move doors in plenum from heat to AC and to fresh air. Search forum for fixes that others have used.
Gary B

Re: Need Help With Dash A/C Problem .....

Reply #18 – July 12, 2014, 12:34:19 pm

I can't be sure about a U225, but in general the air box (air distribution box) is mounted to the inside of the firewall. Under the glove box you'll find panels made out of plywood that you need to remove. They will have carpet stapled to them that you need to pull back in the corners and anywhere else there might be attachment screws.

Re: Need Help With Dash A/C Problem .....

Reply #19 – July 14, 2014, 12:15:39 am

Here's link to my old post on replacing the heater core, which shows what to do to get at the whole heater box with AC evaporator (on 99 U270, which should be similar to yours).

Heater core replacement

Re: Need Help With Dash A/C Problem .....

Reply #20 – July 29, 2014, 08:45:50 pm

Can somebody with a coach in the 96-2000 range look at their reciever/drier and tell me if yours has the pressure switch mounted on it?

Mine has the switch mounted on the reciever drier (driver side, behind wheel, under access cover). But, mine also has a hi and a low pressure switch mounted on their respective hoses right at the compressor---but only the HI pressure cutout switch is wired up.

I blew the high pressure hose going from compressor to condensor and I'm going to replace the drier, expansion valve, pressure switches, and thermostat switch while I'm at it.

Re: Need Help With Dash A/C Problem .....

Reply #21 – July 30, 2014, 10:03:11 am

I believe this is mine on a 98 and I don't see a pressure switch.

Re: Need Help With Dash A/C Problem .....

Reply #22 – July 30, 2014, 12:44:23 pm

Mine looks very similar to the picture above, and I see no evidence of a pressure-switch.

Re: Need Help With Dash A/C Problem .....

Reply #23 – July 30, 2014, 02:38:17 pm

Thanks for the picture and information, both of ya'll. Mine has the drier #054-00019 on the PDF below or in this picture the follows. The wire running to the switch on the drier (it's both a hi-pres cuttout and low-pres cuttout) is connected into the wires at the compressor switches.

So it looks like somebody did some modifications....which is why the unit ran even with low freon charge! The low pressure switch on the drier is pretty worthless unless all the refrigerant goes bye-bye. I'm going to reconnect the low side pressure switch.

http://comfortairgr.com/wp-content/uploads/2013/03/vcs054-00019.jpg

http://www.victoryclimatesystems.com/pdfs/rv/RECEIVER%20DRIERS.pdf

I l

Re: Need Help With Dash A/C Problem .....

Reply #24 – July 31, 2014, 08:08:31 pm

Some more tidbits of info. I couldn't find a legit model number on my A/C compressor, nor was there a manufacturer name. I need to look up the type and amount of oil recomended. When my line blew, I lost a fair amount of oil, and I am replacing the drier and TXV and blowing out lines.

The link above leads to this page on compressors and visual identification shows I have a QP16-1195
http://www.victoryclimatesystems.com/pdfs/rv/compressors.pdf

Google leads to the manufacture website which has all the models listed and a PDF with a drawing/dimensions/basic design criteria including oil type (PAG 46) and volume required.
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