PEX sizing

Users who are viewing this thread

MikeyVon

New Member
Messages
26
Reaction score
0
Points
0
Location
California
I am planning my supply runs and I have heard differing accounts on what size pex to run.

I have 1" copper coming into the house from a 1" meter. I am unsure of what kind of pressure to expect. The meter is around 500' away with about 150' elevation rise to the house.

I was planning on running a Trunk/branch type plan. with 2 main 1" trunk lines. Here are the fixtures and pex sizes I plan on running.


Bath 1/Kitchen (they have a shared wall) - 1" trunk line T'd off main branch:

Vanity - 1/2"
Toilet - 1/2"
Tub/shower combo - 3/4"
Kitchen Sink - 1/2"
Ice Maker - 1/2"
Dishwasher (supplied off the kitchen sink line?)
Hot/Cold outside house bib - 3/4"

Master Bath - 1" trunk line (main branch):

vanity x 2 - 1/2"
toilet - 1/2"
Steam generator - 1/2"
Shower - 3/4"
Soaker Bath - 3/4"
Hand held for bath - 3/4"

Other fixtures running off main branch -

hosebibs x 2 - 3/4"
Utility Sink - 1/2"
Washer - 1/2"

Does this setup sound ok? I have heard 3/4" trunk lines should be ok, but I also have folks telling me that I should use 1" to be on the safe side.

Should I run the hot side as 1" also or 3/4"? I was assuming I would use 1" also out of the water heater.

thanks,

Michael
 

MikeyVon

New Member
Messages
26
Reaction score
0
Points
0
Location
California
California Code Questions - Water Heaters

I have some quick questions regarding CA code. This is for new construction.

I have an at grade basement (walkout) and I would like to put my water heater there. It will be either a direct vent or power vent. There is no problem with this correct?

We use woodheat as our primary heat source and rarely touch anything else. we will be using staple-up radiant as our heat source for code. We do not plan on using it much and would like to use a water heater as our heat source. We will seperate the systems using a heat exchanger.

Is it ok per code in CA to use the water heater for DHW and radiant heat, as long as the radiant is a closed loop using a heat exhanger?

thanks again,

michael
 

Terry

The Plumbing Wizard
Staff member
Messages
29,942
Reaction score
3,458
Points
113
Location
Bothell, Washington
Website
terrylove.com
I can see 3/4" for a large soaking tub.

Unless you have mutiple heads, and body sprays on the shower, 1/2" would be plenty.

Two lavs can be run on 1/2"
If fact, with PEX, sometimes 3/8" is plenty for some fixtures.

How long is the home from the water heater to the farthest fixture?
What brand of PEX are you running?

https://terrylove.com/watersize.htm
 

MikeyVon

New Member
Messages
26
Reaction score
0
Points
0
Location
California
I will be running aquapex (wirsbo) with the propex tools.

The longest hot water run is about 40' to the kitchen sink.

So could I use 3/4" lines as my main trunk lines? or should I use 1"? With 3/4" trunk lines, I was concerned about pressure drop when using multiple fixtures.

My carpenter used 1/2" PEX lines on his house and says it is not enough, but it is also a function of pressure correct? He says he has low pressure. I am concerned about the pressure at my house do to the distance and elevation gain from the meter.
 

Lakee911

I&C Engineer (mostly WWTP)
Messages
1,254
Reaction score
1
Points
0
Location
Columbus, OH
If you measure the pressure at your meter, then you can subtract your elevation change and your frctional losses in the pipe.

150 ft elevation change (150 ft w.c) is 65psi.

If you're water is moving around 2ft/sec through that pipe, you're looking at 5 psi for the pipe. So you'll need to overcome 70psi from loss alone.

My pressure at home is around 65, so I hope that at your meter it is quite high!

Jason
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks