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Old 01-18-2016, 04:54 PM   #1
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1972 Argosy 22
Shalimar , Florida
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Fresh water pipe diameter

Going with PEX IN A 72 Argosy 22, confused about the copper to PEX connections. Bought a 3/4 and 1/2 adapter, fits the PEX fine but will not mate to the copper coming from the fresh water tank or the hot water heater inlet. What am I doing wrong? Thanks Jim
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Old 01-20-2016, 08:58 PM   #2
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2008 F350, 6.4L diesel , Oak Harbor, WA
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Are you connecting at the water heater?
My unit is a 1986 and it used polybutylene tubing instead of the copper. My guess is that you would need either to come off the WH with a male pipe thread adapter or a ferrel fitting adapter.

In my opinion starting at the WH is by far the most rugged and most reliable.
If you are just getting started I would purchase a PEX crimp style tool, not very much money $30 and use crimp rings. Should be less expensive in the long run and you won't need to worry about the connections.

If you are worried about getting the PEX into hard to reach places you can tie a cord onto the old pipe and just pull the pipe out, then you can pull the PEX in. I did not find any of the tubing installed with hidden clamps tight to the trailer, it all came out with little trouble.

Just going to PEX will increase your system performance and be nearly bullet proof for freezing.
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Old 01-21-2016, 12:00 AM   #3
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You are dealing with copper tubing not copper pipe. Tubing is sized by outside dimensions. Pipe is inside dimensions.
Not sure why you are leaving some copper in the coach other than the hot and cold lines going to the shower faucets. Everything else should be relatively easy to replace with PEX.
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Old 01-21-2016, 08:48 AM   #4
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Fresh water pipe diameter

For copper tubing sizes see this
The likely reason why the PEX fittings won't work on your copper is because the copper expanded from frozen water inside of it.
When I went to check the water system on our new to us 75 Overlander (with air first) it leaked. Checked PO receipts, many for water leak repair. Started checking repairs and remaining copper, a disaster! Much of the copper that wasn't split, had expanded to a new dimension you can't purchase.
So the copilot and I talked, we went to the store, $500 and a couple of days later ALL of the fresh water plumbing was on PEX with new faucets and valves.
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Old 01-22-2016, 12:44 PM   #5
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1977 31' Sovereign
Lynnwood , Washington
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Those threads are probably 5/8 "tubing" - different stuff than "pipe."

Get a brass fitting adapter = 5/8" tubing to 1/2" pipe. Ace is the place.

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Old 01-22-2016, 05:06 PM   #6
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South of the river , Minnesota
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Originally Posted by Andersojd View Post
Going with PEX IN A 72 Argosy 22, confused about the copper to PEX connections. Bought a 3/4 and 1/2 adapter, fits the PEX fine but will not mate to the copper coming from the fresh water tank or the hot water heater inlet. What am I doing wrong? Thanks Jim

It is not unusual for older Airstreams to have copper tubing that has been subject to freezing temperatures while containing water. This causes the diameter of the pipe to expand slightly, and it will no longer fit into standard fittings.

The best fix is to replace all of it. Failing that, it may be possible to solder a short piece of new copper pipe inside the old expanded copper pipe, to get a piece of standard size.
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Old 01-22-2016, 06:32 PM   #7
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1977 Argosy 28
Euless , Texas
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copper tubing size

Early Airstreams typically have copper tubing not plumbing pipe and is sized differently. This type of pipe is typically used in air conditioning systems. I went to a refrigeration supply house to get a proper size splice to fix a broken line when I got my '77 and it was only a couple of dollars. I believe they also had pieces to solder in to convert to plumbing pipe sizes.
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Old 01-22-2016, 08:10 PM   #8
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Just a corollary to the above;
Many of you use those "Y" valves to connect two or more hoses to the city water bib, and/or use those related little shut Off Valves. (SOVs)

Going with an RVTravel.com suggestion, I installed a little SOV at the water inlet to the trailer, so that I could shut off the water when we went out for the day; To preclude possible problems from leakage. However......

The water flow was rather slow to the AS, and troubleshooting, I found that those valves, and the 'Y's have a 5/16" passageway, where-as, my hose was 5/8" dia. See the problem?
I went to the hardware store, and purchased a 1/2" SOV, drilled out some threads to accept some purchased male/female hose ends and squeezed them together with some epoxy. Now, It works fine.
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