I have the old grey poly/class action suit pipe now and I'm changing to pex in my double wide. Currently it is 1/2 inch and I am wondering what benefit I would have by going to 3/4? Also I read each line should be a home run to a main manifold, is that accurate? Longest line would be 35 feet with 9 branches off it and then the hose hookup. Any help would be greatly appreciated... Thanks.

Pex is the same size as PB so if you did not have any problems previously, you can just duplicate what you have now.

Would I gain anything from going to 3/4? And your saying I wouldn't need a home run on each line? I just don't wanna lose any pressure. Thanks

i am partial to the home run method.
no joints in the pipes except the beginning and the end.

By code 2 fixtures is all you can have on 1/2". I would run a 3/4" main and branch off with 1/2".

home run systems seemed to have been more of a trend or fad.. they are neat and nice. To me I would run a 3/4 pex and branch off to fixtures... rule of thumb is max 2 fixtures on a half inch line-so on your bathroom cold -after your first fixture you can downsize to 1/2. and pex is not the same as polyb; pex is still an acceptable choice.

Thanks for all the insight guys! I like the 3/4 branch to 1/2 idea. Is that code just where you are or nationally? Thanks

I'm pretty sure that's nation wide.

OK great thanks! One last question, push or clamp fittings. Its in the belly of double wide so which would be the least problematic for the future.

Mobile homes are "compact" so there are very few "long" runs. You MIGHT gain a little bit by increasing the size, but I doubt that you would notice the difference.

Mobile homes are under their own codes. Plumbing codes do not apply to them.

quote; Is that code just where you are or nationally? Thanks

It is a plumbing practice, but plumbing codes do not apply to manufactured housing.

"Problematic in the future" should not be a factor if you install it correctly in the first place.

Yes I know that and I don't do anything half arse but my wondering is if one fitting is better than the other. Ty

Quote

OK great thanks! One last question, push or clamp fittings. Its in the belly of double wide so which would be the least problematic for the future.

That is precisely why 'home run' system is best.

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

So if I go with home run setup is 1/2 inch throughout acceptable?

Do not use those push on fittings, use the crimp style polymer fittings. If it were mine I'd rather have a main line with branches instead of a manifold system .

Just curious as to why some would rather branch with PEX vs having a manifold with home runs. What are the issues with a manifold setup?

Manifolds are more expensive, take more time to install, take much more piping, can't use a recirculating line, hot water usually takes longer to reach a fixture, normally doesn't look as neat and professional as a straight line with branches.

if copper:
3/4 main with 1/2 branches


if PEX:
1/2 home runs using an individually valved manifold (the manifold valves would take the place of individual fixture stops)

just my opinion

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Define "better". I would have no problem using the crimp or "cinch" fittings, but some swear by the Wirsbo expansion ones.

Usually long runs from the manifold to the faucets. In some instances, the installers use 1/4" or 3/8" from the manifolds to the faucets to minimize the amount of 'stagnant' water in the line.

I would still prefer the stops at the fixtures, but if they did not have them, I would turn off the water to the whole house before I would use the manifold valves. I have had them fail when operated on OR off, so I don't touch them.

by push fittings do you mean "sharkbite"? I think you will find that renting crimpers and buying pex fittings will be more cost effective. A rundown of your line =3/4 pex by poly b to water heater. (if gas water heater might as just run copper to it-code thingy) then out of water heater... 3/4 then 3/4 3/4 1/2 t to kitchen. then 3/4 3/4 1/2 t to laundry then 3/4 3/4 3/4 tee to bathroom then 3/4 3/4 1/2 t to lav faucet and 3/4 1/2 coupling to shower. copy last to pick up ensuite.

quote; A rundown of your line =3/4 pex by poly b to water heater. (if gas water heater might as just run copper to it-code thingy) then out of water heater... 3/4 then 3/4 3/4 1/2 t to kitchen. then 3/4 3/4 1/2 t to laundry then 3/4 3/4 3/4 tee to bathroom then 3/4 3/4 1/2 t to lav faucet and 3/4 1/2 coupling to shower. copy last to pick up ensuite.

WOW! You are good. Most of us would have to actually SEE the job to make up a material list, but you can do it from just a minimal E-mail posting.

So I have a few options here I see. Looks like I'll think it over and do what I think is best from all the advice and personal preference. Thanks for all the help!

not really good... forgot the hosebib. and I admit it could be different material take off list .

quote; replace the stems with newer style washer stems.

"mobile homes" may only have one on the copper line before it enters the house. But usually the only one the DO have is on the riser out of the ground which supplies water to the coach.