Location of the Dash Air Expansion Valve on a 2003 U320

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Location of the Dash Air Expansion Valve on a 2003 U320

September 06, 2014, 04:04:27 pm

My Dash air started blowing the circuit breaker. After troubleshooting the problem it appeared to be a bad compressor clutch. After replacing the clutch the circuit breaker no longer tripped but now I have no cold air. After connecting up the machine to check refrigerant it looked like a clog on the low pressure side creating a vacuum. Wanted to check the expansion valve. I have had to remove the entire dash to get in there and it is nowhere to be found. Don't know if I could replace it if I did locate it without disassembling the entire dash.
Has anyone with a 2003 located the expansion valve, had to replace it and how did you get to it. A photo would be wonderful.
A previous post mentioned some desiccant was clogging his. Already have done all James Triana's suggestions regarding removing all the dash panels.

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #1 – September 06, 2014, 09:50:31 pm

Normally if the suction side goes into vacuum it would indicate that the dissicant bag in the receiver / dryer has failed and dissicant beads and bag particles have clogged the expansion valve. I'm no expert, but you will probably need to flush the whole system in addition to changing the receiver / dryer and expansion valve. Not sure where it is located on the 2003, but seems it should be near the evaporator.

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #2 – September 06, 2014, 10:21:41 pm

I can't help you with an exact location but the expansion valve will be very close to the evaporator, and after the receiver/drier.

TOM

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #3 – September 07, 2014, 10:42:18 am

If you can locate the refrigerant hoses, you should be able to follow them to where they connect to the evaporator. My TXV was connected right there.

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #4 – September 07, 2014, 05:02:57 pm

Quote from: rsihnhold – September 07, 2014, 10:42:18 am

If you can locate the refrigerant hoses, you should be able to follow them to where they connect to the evaporator. My TXV was connected right there.

On passenger side I show 4 rubber hoses, 2 for the aquahot core that go into the floor.
The 2 front rubber hoses come from the back of plenum (Front of Coach) down into the floor to the heater valve and I see nothing on it.
When it goes into the plenum it changes to copper. I think it has to be in that plenum where I can't get to it. I see no easy way into the plenum without tearing the dash out underneath and would probably create too much damage to wires and hoses compounding my problem. Everything is just too tight in there to be able to work effectively.

Also there is no capillary wire that I can follow to the expansion valve.

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #5 – September 07, 2014, 05:09:44 pm

It's not normally inside the plenum, usually it is right outside. Are you sure your system uses an expansion valve, or is it equipped with an orifice tube? Later automative AC units went to the orifice tube, but I don't know about the 03' U320

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #6 – September 07, 2014, 05:33:09 pm

Two of the rubber hoses are for the Aquahot and two are for the heater core supplied by the engine coolant. You are still looking for two more lines.

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #7 – September 07, 2014, 08:58:49 pm

The two you are looking for will have flare fittings, not hose clamps

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #8 – September 08, 2014, 06:11:43 pm

Quote from: sedelange – September 07, 2014, 05:33:09 pm

Two of the rubber hoses are for the Aquahot and two are for the heater core supplied by the engine coolant. You are still looking for two more lines.

Mystery Solved:
After many emails with James T. and a diagram showing where it is and confirming he looked at another 2003 and verified it was there and you saying I am looking for 2 more lines, I took another long look.
I FOUND IT buried in foam towards the front looking like part of the bulkhead just where it was supposed to be. Until I removed some of that foam I could not tell there was hoses there. Talk about an optical illusion. Now to finish troubleshooting and figure out how to get two hands in there to replace it if necessary.

You have to take off the front dash panel and the passenger side panel to get a good look at it between all those wires.

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #9 – September 08, 2014, 07:39:12 pm

Wow, what a maze in there! You are making headway now.

Richard B

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #10 – September 08, 2014, 07:55:54 pm

With that type of expansion valve you are going to find two more fittings opposite the two you see. You are going to be remembering lots of words before you get that out.

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #11 – September 08, 2014, 09:54:26 pm

Barry, I had similar symptoms; cycling of the A/C clutch, caused by the CB under the bed tripping and resetting. I usually make pretty good notes on repairs, but if I did I can't find them. I took it to a shop. I know the tech bypassed the CB before starting his diagnostic tests. With the CB bypassed the compressor pump ran constantly when dash controls were properly set. He then hooked up his gauge set. Next he sucked out and weighed all the refrigerant and then replaced the refrigerant. Here is the only note I can find on this.
"Truck shop in Salem, OR diagnosed the cause as a failed compressor pump. They replaced the compressor and the receiver drier today and the operation is normal; in fact better than it has been for the 2 years we have owned this.
I'm not 100% sure it wasn't just the clutch though. The tech based his decision on the fact that the high pressure didn't go above 150 psi. Turns out the new compressor didn't either. A different tech installed the new unit and he thought it didn't go up to like 250 psi was because motorhomes have a constant fan blowing on the condenser. I don't know, but I'm glad they replaced the whole thing."
I am attaching a chart I got from them.
Hope you get this figured out and fixed.
Dick

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #12 – September 08, 2014, 10:54:22 pm

Barry, sorry I'm late to the show, but I was at a show for the last few days!

I was the one that just did repairs and replaced TXV on my 98.

Your newer coach appears to have what I would call expansion block style TXV (my words, not sure if they are offical). Anyway, it looks like one of the ones here. My 98 uses the 34-00029.

http://www.victoryclimatesystems.com/pdfs/rv/expansion%20valves.pdf

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #13 – September 13, 2014, 09:15:07 am

Quote from: krush – September 08, 2014, 10:54:22 pm

Your newer coach appears to have what I would call expansion block style TXV (my words, not sure if they are offical).

You are correct. Got it replaced and replaced the drier also. Both parts relatively inexpensive. Blowing out at a nice 46 degrees.

Now to get this dash put back together.

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #14 – September 13, 2014, 09:30:25 am

Barry,
Nice work! I know your dash is different, the newer style, but if you can take yours apart without destroying it, then it must be possible on mine

I still haven't located our auto generator start, it isn't where others have posted pictures of but I know it's their somewhere! Also, where is your A/C dryer located? I think I will need to be replacing ours pretty soon.
Don

Quote from: Barry Beam – September 13, 2014, 09:15:07 am

You are correct. Got it replaced and replaced the drier also. Both parts relatively inexpensive. Blowing out at a nice 46 degrees.
Now to get this dash put back together.

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #15 – September 13, 2014, 09:34:56 am

Barry,
Thanks for posting this thread and the images of the valve replacement.

It is a little late to ask now, but do you have more images of how you dismantled the dash area to get to the expansion valve? Specifically, how the bits and pieces came off, which came off and how they went back on.

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #16 – September 13, 2014, 09:36:41 am

Quote from: acousticart – September 13, 2014, 09:30:25 am

Barry,
Where is your A/C dryer located? I think I will need to be replacing ours pretty soon.
Don

Attached to the condenser as you lift up that door it is right there.

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #17 – September 13, 2014, 09:52:07 am

Quote from: Jan & Richard – September 13, 2014, 09:34:56 am

Barry,
Thanks for posting this thread and the images of the valve replacement.
It is a little late to ask now, but do you have more images of how you dismantled the dash area to get to the expansion valve? Specifically, how the bits and pieces came off, which came off and how they went back on.

The top pieces are all held on with velcro. As I pulled them up all the velcro came off the panels. The glue is not strong enough to withstand the pulling up of the panel. So I will have to replace all the velcro. The center section is built on a 1/4" piece of masonite screwed to the floor and on the side. That whole assembly comes out as 1 piece including the drawer. In the center hole I can see the dash air blower and the other hole I can see the windshield wiper assembly. I have not put it back together yet. As long as I went this far I might as well try and identify everything that is in there for future reference.

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #18 – September 13, 2014, 10:37:58 am

This is VERY timely. The dash-air on our '98 U320 has quit producing anything cooler than room-temp and replacing the compressor and dryer didn't remedy the situation. So .... it looks like I will be dismantling our dash. Until viewing Barry's work, I had hopes I could reach things by removing the dash top. I see now "no-such-luck". Thanks for the posting, Barry!!

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #19 – September 13, 2014, 10:47:26 am

Great job Barry! What part number is the TXV ?
No wonder they charge so much for labor to work on these A/C systems.

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #20 – September 13, 2014, 08:36:54 pm

Quote from: rbark – September 13, 2014, 10:47:26 am

Great job Barry! What part number is the TXV ?
No wonder they charge so much for labor to work on these A/C systems.

MEI1600 Airsource Expansion Valve Block Type - 1600
Expansion Valve Block Type, 1600, Airsource
A/C Receiver Drier-Filter Drier 4 Seasons 33317

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #21 – September 13, 2014, 08:49:55 pm

Sticky? pc

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #22 – September 14, 2014, 11:12:37 am

Found the attached TXV write-up helpful

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #23 – September 14, 2014, 04:54:07 pm

Nice write up Barry, but what the heck is SINDA/FLUINT stand for? $:-\$

Re: Location of the Dash Air Expansion Valve on a 2003 U320

Reply #24 – September 14, 2014, 09:23:01 pm

Richard,

It has been a while but when I worked SINDA/FLUINT was heat transfer analysis and fluid analysis system.

Pamela & Mike

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