Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Plumbing

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 05-04-2010, 09:21 PM   #1
Member
 
Join Date: Jul 2009
Posts: 94
Rewards Points: 75
Default

water supply size


If I have a 3/4 pipe entering my house from the water supply, is there any benefit from using a 1" pipe to run the water supply throughout the house.
Also,this 1" will be cold water, does it matter that the hot water pipes are 3/4". The material L copper.

Thanks.

sharp is offline   Reply With Quote
Old 05-04-2010, 09:35 PM   #2
Member
 
waterman1971's Avatar
 
Join Date: Apr 2009
Posts: 161
Rewards Points: 150
Default

water supply size


Reduced velocity could add to the life of the plumbing. Why is this even a consideration? Maybe on your washing machine or dishwasher? Just thought i'd chime in.

waterman1971 is offline   Reply With Quote
Old 05-04-2010, 09:44 PM   #3
Member
 
Join Date: Jul 2009
Posts: 94
Rewards Points: 75
Default

water supply size


I'm in the middle of a major renovation and where I'm living now the shower loses water pressure whenever any other fixture is running. This is something I want to avoid. My house is 80 years old. It seems new construction comes with a 1" supply line coming into the house. I only have 3/4 coming in. Don't want to change that, but wanted to know if continuing from the supply 3/4 with a 1" if that would reduce the chances of losing water pressure in the second floor shower when the washing machine and diswasher are running.
sharp is offline   Reply With Quote
Old 05-04-2010, 09:50 PM   #4
Member
 
waterman1971's Avatar
 
Join Date: Apr 2009
Posts: 161
Rewards Points: 150
Default

water supply size


The water pressure will not change regardless of the diameter of the piping supply line. The volume of water you can deliver, however, will increase as the diameter increases. Try measuring the flow rate at the new location vs. the old. If the difference is significant perhaps increased diameter could help. Maybe there is an obstruction somewhere, galvanized nipple or something?

Last edited by waterman1971; 05-04-2010 at 09:54 PM.
waterman1971 is offline   Reply With Quote
Old 05-05-2010, 09:16 AM   #5
Member
 
Join Date: May 2010
Location: Massachusetts
Posts: 133
Rewards Points: 75
Default

water supply size


There are two type of pressures in your system, the static pressure under no flow will remain the same no matter what diameter pipe your running, you'll only lose pressure to elevation because of the 2nd floor. Once you open a valve and start flowing water the pressure drops down to a "residual" pressure based on your flow, pipe size and friction loss. If your 1" pipe run is any significant distance, you will gain back some of the friction loss, but if your run is short, any gain in pressure will be mimimal. For example, if your 3/4" service is 100 feet long, and you run a 1" pipe after the meter only 25 feet, you won't gain much pressure. But if your 3/4" service pipe is 25' long, and you run a 1" pipe 100 feet after that, the friction loss gained will be more significant.
The Engineer is offline   Reply With Quote
Old 05-05-2010, 10:06 AM   #6
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Rewards Points: 2,000
Default

water supply size


(1/0.75)^2 = a factor of 1.8 larger in pipe capacity.

Try these guys for some numbers
http://www.engineeringtoolbox.com/eq...hod-d_804.html

The friction loss depends on the water velocity squared, and velocity depends on GPM and pipe size.

IMO the public water supply acts more like a 'pressure source' [constant pressure regardless of flow rate over a zero to 13 GPM range]
rather than acting like a 'flow source' [pressure adjusts to provide a constant flow].

Like Mr. 1971 said, what is your shower GPM, with and without other fixtures running? All you need to check this is a known capacity container and a watch. I'm sure it's less than 6 GPM in any case.


Last edited by Yoyizit; 05-05-2010 at 10:57 AM.
Yoyizit is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Water Inside/Around American Standard Furnace michrob HVAC 8 12-08-2011 03:51 PM
water borehole question joeuser General DIY Discussions 2 04-18-2010 10:33 PM
No water draining into sump pit aci4369 Plumbing 2 08-18-2009 12:17 PM
bad valve washing machine?? drdon51 Plumbing 6 06-29-2009 01:02 PM
Very Low Hot Water Pressure. PAS1970 General DIY Discussions 2 02-25-2009 03:01 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.