| [GMCnet] PEX tubing questions [message #365221] |
Sat, 03 July 2021 09:17  |
Stu Rasmussen
Messages: 130
Registered: January 2019
Location: Silverton, OR
Karma: 0
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Senior Member |
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Reading the recent thread about changing 40 year old water lines for
PEX engendered two questions:
1: What size PEX would be suitable to get the same flow as the
existing piping?
2: Is PEX burst-resistant enough to re-route the replacement piping
under the coach (easy) instead of snaking it through the existing
routing (convoluted)? I'm thinking here about resistance to bursting
due to freezing.
Inquiring minds and all that . . . .
Stu
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Stu Rasmussen W7QJ
Silverton, OR
'77 Birchaven
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| Re: [GMCnet] PEX tubing questions [message #365237 is a reply to message #365221] |
Sun, 04 July 2021 00:00  |
Green machine
Messages: 184
Registered: July 2019
Location: North Vancouver BC
Karma: 5
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I redid all my water lines with half inch pex. Color coded blue and red. I didn't go under the coach but would have no problem doing it. Just put a drain cock at a low point and you'll be fine.
Shawn
Shawn Harris
North Vancouver,
Canada
1977 Palm Beach 403
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| Re: [GMCnet] PEX tubing questions [message #365297 is a reply to message #365221] |
Fri, 09 July 2021 09:07 |
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Richard RV
Messages: 631
Registered: July 2012
Location: Full-timer for 12 years, ...
Karma: -17
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Stu,
3/8" and 1/2" are the two most common PEX line sizes, with 1/2" being the most common in residential construction. It may not be desirable to have high flow in an RV, particularly one with smaller holding tanks like a GMC. If you're frequently at campgrounds and hooked up to the sewer than flow rate and holding tank filling efficiency doesn't matter. Generally speaking, a 3/8" line will deliver good flow.
The 1/2" line will have a flow rate ~2.5x that of a 3/8" line. If you're planning on having an "instant water heater" it will require a higher flow rate to trigger the heat, which might be at the upper end (or beyond) what a 3/8" line can deliver.
I don't know that counting solely on the freeze resiliency of PEX is wise. Running the water lines under the coach means that they'll freeze sooner than if they're inside the coach. If the line freezes water won't flow. You could insulate and/or heat trace them to compensate if you're frequently camping in colder weather.
Of course you will still need to winterize the coach, and your drain valves will be at the lowest point and underneath the coach, so you'll have to get under the coach to winterize instead of doing it from inside.
Richard
'77 Birchaven TZE...777;
'76 Palm Beach under construction;
‘76 Edgemont waiting its turn
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| Re: [GMCnet] PEX tubing questions [message #365315 is a reply to message #365221] |
Fri, 09 July 2021 20:35 |
dsmithy
Messages: 210
Registered: July 2012
Location: Lincoln Nebraska
Karma: 0
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Senior Member |
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Stu,
I redid my '73 with half-inch pex and did not find it too difficult to get access and pull tubes without taking much apart. Yes, the over the ceiling runs were the worst but not bad. If you use whatever's existing as a puller it's not a difficult job. Can't speak for the differences between '73 and '77 for this task.
Doug
Douglas & Virginia Smith,
dsmithy18 at gmail,
Lincoln Nebraska,
’73 “Sequoia” since ‘95: "Wanabizo";
Quadrabag/6 wheel disks/3:70 final/Paterson QuadraJet/Thorley’s/Alloy wheels/Sundry other
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| [GMCnet] Re: PEX tubing questions [message #365320 is a reply to message #365315] |
Fri, 09 July 2021 23:00 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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I used 1/2” pex in The War Pig and it was fairly easy to pull into place.
The struggle I remember was bending long runs around corners. Yeah I
could’ve used a brass elbow and two more compression fittings but I wanted
to minimize the number of connections. The support bracket for pex 90s has
a pretty large radius.
Sully
Bellevue wa.
On Fri, Jul 9, 2021 at 6:35 PM Douglas Smith wrote:
> Stu,
> I redid my '73 with half-inch pex and did not find it too difficult to get
> access and pull tubes without taking much apart. Yes, the over the ceiling
> runs were the worst but not bad. If you use whatever's existing as a
> puller it's not a difficult job. Can't speak for the differences between
> '73 and
> '77 for this task.
> Doug
> --
> Douglas & Virginia Smith,
> dsmithy18 at gmail,
> Lincoln Nebraska,
> ’73 “Sequoia” since ‘95: "Wanabizo";
> Quadrabag/6 wheel disks/3:70 final/Paterson QuadraJet/Thorley’s/Alloy
> wheels/Sundry other
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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