question for our plumbers

[wormdunker]

Hopefully we have a plumber or 2 on board. I'm renovating my basement laundry room. Presently I have 1/2" copper feeding my gas fired hot water tank & 1/2" out to feed the rest of the house. The 2 pipes are in the way of a new wall I want to frame, so, I'd like to relocate them. While I'm at it I thought of increasing the size to 3/4" to have better water flow to the other fixtures, namely the new shower, toilet & sink in the lower level. What are your thoughts. Thanx I am well versed on soldering copper, & more recently changing over to Pex. I love the Pex!

[Gerritt]

While I'm not a plumber, I have been involved in the trades for years, if you have 1/2" coming in from the street upgrading to tank to 3/4" is a moot point. You my see a slight increase in volume of water.... But it is probably negligible at best.

 

Changing the diameter of the piping does not increase pressure, only water volume.

 

Hope this helps.

 

G

[G.mech]

If you increase the cold water line size to 3/4" at least as far as where hot water tank is it will make a big difference even if you leave the hot and cold downstream of the water heater at 1/2". Most of the time you are using a mixture of hot and cold anyway so the flow rate in the 1/2" pipes is roughly 50% of the flow rate in the cold water supply line to the tank. My house had about 50 feet of 1/2" pipe from the meter to the tee at the hot water heater and increasing this piece to 3/4" made a world of difference. As Gerritt points out however, this is based on the assumption you have a 3/4" supply from the street.

Edited January 14, 2016 by G.mech

[Fisherman]

Hopefully we have a plumber or 2 on board. I'm renovating my basement laundry room. Presently I have 1/2" copper feeding my gas fired hot water tank & 1/2" out to feed the rest of the house. The 2 pipes are in the way of a new wall I want to frame, so, I'd like to relocate them. While I'm at it I thought of increasing the size to 3/4" to have better water flow to the other fixtures, namely the new shower, toilet & sink in the lower level. What are your thoughts. Thanx I am well versed on soldering copper, & more recently changing over to Pex. I love the Pex!

I did a bunch downstairs with the PEX type tubing but used the Sharkbite fittings. Man is that easy work.

[davey buoy]

Your outlet line is 1/2",the only thing a larger pipe will do after that is give you a quick rush when you open a valve.Your flow is only as big as your smallest pipe.If from the road is 1/2",not much you can do to change the constant flow.

[Old Ironmaker]

Don't forget Brian that that fixture you are plumbing may have 1/2 most likely 3/8 supply to the fixture. So it won't give you more flow, plus the non removable flow reducer at the spout to save water.

[OhioFisherman]

I am open to correction on this.

 

Double the size of the pipe and the amount of water capable of flowing thru it multiplies x4. If you have a half inch line coming in and increase the size of other lines to 3/4? You may lose water pressure? The amount of water flowing thru the 3/4 pipe is limited by the supply?

 

I am sure Joe or Art could give you a better answer.

[Muskieman]

Thinking engine exhausts and hydraulic hoses here , but ... wouldn't a smaller diameter line give you more pressure ?

[OhioFisherman]

The same principle I believe Randy, ever use one of the garden hose fittings that cuts the outlet diameter? The water has more pressure and goes farther?

 

Engine exhaust wasn't a constant like water flow into a home, with a high performance engine you wanted to increase the pipe diameter to improve flow at high RPM.

[wormdunker]

Good info here. Thanx guys. I'll go further to explain my existing conditions. I have a water softener. Presently 3/4" copper from the street to the valves which controls my softener. After these 2 valves it's 1/2" copper supply to the hot water tank. The ceiling joists are wide open - so, easy access. That's one of the other reasons to do the change at this time.

Gerritt - Yes I would probably install 3/4" right from the softener shut off valves, until I read Ironmakers post about the 3/8" fittings of the fixtures.

Fisherman - Shark bite fittings are awesome! Very expensive! I have used them in extremely tight areas.

Old Ironmaker- Good point about the 3/8" supply lines found on most sink, toilet & shower fixtures. So it sounds like 3/4" lines is a moot point as stated by Gerritt.

 

Now this gets confusing. When I installed my underground lawn sprinkler system I was able to use more heads per zone by using 3/4" plastic pipe than if I were to use 1/2" due to more water flow, but as Gerrit stated it increases the water flow, NOT pressure.

[Old Ironmaker]

Pressure remains constant throughout a system. If ID of a line is reduced velocity increases.

[wormdunker]

Thanx guys. I completed the job earlier today decided to use the 1/2" Pex. Nice material to work with. ID of the pex is 3/8", which is the same as the supply lines to my fixtures.

[aplumma]

The pipe rating for 3/4 copper is 72 fixture rating meaning I can supply that number of outlets and still hold the pressure within acceptable limits in water pressure loss. The rating of 1/2 inch pipe is 2 fixture ratings. It means If we have one 3 fixture bathroom then it can be plumbed 1/2 hot water one for the tub one for the sink. The cold water feed is 3/4 meaning up to the bathroom we would have a 3/4 tee with 2 1/2 outlets to be within code. The effects of pipe size is pressure drop as other fixtures are turned on and the friction loss of piping. The friction loss of copper is the least loss while plastics are a major loss as distance increases. Given a static pressure all pipes will go to example 50 lbs with no flow. Turn on a faucet that is equal to the flow in the pipe and you will have no pressure loss but have a flow rating of the pipe. This means a 3/4 pipe will flow 20 gallons a minute while a 1/2 will flow 4 gallons a minute ( numbers are for examples only). If you add the friction loss of plastic or galvanized and you can drop even more. This is all part of the local codes and engineering in the USA they are our guidelines we use while the physics are universal the code requirements are different from code governing rules that Canada follows. The last thought of volume and velocity is as you create back pressure by making a drop in pipe size you are not increasing the pressure greater than the feed pressure you are only creating lower volume without a decrease of pressure. If you start with 50 lb 1/2 and 50 lb 3/4 your bucket will fill faster with the 3/4..

 

Art

[wormdunker]

Thanx Art. I appreciate your input, I'm still attempting to decipher it!! LOL! If I understand it correctly perhaps I should have used 3/4" to the bathroom, then use a "T" (3/4" to 1/2"). 1/2" to feed the sink, 1/2" to feed the shower, 1/2" to feed toilet?? Am I close?

[Jigger]

As a rule of thumb, you should run 3/4" to the last 2 fixtures served. If you"re using PEX, a manifold is the way to go for even distribution throughout a bathroom group. Like aplumma says, your bucket (hot water tank) will fill much faster with a 3/4" line. Also, when using PEX, use the least amount of elbows/tees/couplings as possible. The ID on the pipe might be 3/8", but the insert fitting is about 1/4".

[aplumma]

Thanx Art. I appreciate your input, I'm still attempting to decipher it!! LOL! If I understand it correctly perhaps I should have used 3/4" to the bathroom, then use a "T" (3/4" to 1/2"). 1/2" to feed the sink, 1/2" to feed the shower, 1/2" to feed toilet?? Am I close?

The tee input side is 3/4 so we are feeding 72 fixture units of water. the two other outlets are 1/2 inch . Each of the outlets that are 1/2 will feed 2 fixtures. so with the set up we could feed 2 on the left and 2 on the right side of the tee. I am not a pex fan it loses a lot of diameter with fittings as pointed out it is very restrictive also because of the hoops and bends it loses a lot of flow. All of the houses that I have input on I advise copper if not then 3/4 cpvc through out the house using 1/2 only at the final connection. The people that spend the extra 20% all love the way they can run two or three faucets without a pressure loss and temperature change.

 

 

Art

[wormdunker]

Thanx again Art. Now I'm rethinking my installation. I'm not too sure what you mean by "we could feed 2 on the left & 2 on the right side of the Tee?? Would this be a 3/4" to 3/4" Tee, (three 3/4" outlets) then a 1/2" tee after that?? would you be able to supply a sketch? Thanx

 

Jigger - I'm going to take a closer look at those fittings. Proper water flow & constant temperature is what I desire. If I have to change the work I did Thursday - no biggie! It's only 11' of cold & 11' of hot line to remove then install 3/4". I purchased 30' of 1/2" Pex - $9.00? Cheap lesson learned. I'm not sure of the manifold set up you are suggesting?

Edited January 18, 2016 by wormdunker

[Jigger]

Pex is great for installation and is way better than copper in terms of heat loss. If you can get away with straight runs and sweeping bends, you're apt to have better flow than using 90s and tees.

 

Google pex manifold will show an infinite amount of images. The easiest explanation is that it's a 3/4" inlet (in this case anyways), and what would amount to a 1" chamber, with a series of 1/2" outlets down the chamber. As you'll see in the images, it can get pretty crazy with the amount of pipe that can be used!

 

The fitting he's talking about looks like this. Keep in mind I'm on my phone...

 

1/2"

3/4" __ |__ 1/2"

 

Finally, here's a guide to waterpipe sizing here in Ontario. It's just a quick guide but does the trick.

 

http://www.oboa.on.ca/events/2010/sessions/files/410.pdf

 

Edit: For clarity,the tee should be 3/4" on one side with two 1/2" outlets.

Edited January 18, 2016 by Jigger

[aplumma]

 

 

See if this clears it up. The 3/4 is black pipe and the green is !/2 inch.

 

 

art

[Old Ironmaker]

Too small of an image Art too see it well. I was hoping you would have chimed in earlier for Worm Dunker. When I said pressure remains constant throughout a system what I didn't say was if your line diameters size is reduced throughout that system, I should have said "somewhat" constant. We dealt in gases as well as water in the furnaces but more gases. Something about leaving somethings to the experts as one can imagine water cooling the most important when dealing with temperatures up to 3400F.

 

Brian, what did I tell you on the phone? You go to work and they pay you, the "pro" works for you, then you pay him. 2 of the things I pay the guy for is electrical and plumbing.

[Jigger]

As a plumber, I pay for electrical and drywall mudding. Man I hate mudding.

[wormdunker]

Good one Jigger! I'll pay for mudding as well. When mudding, I apply 1, 5 gallon pail & end up sanding off most of it! Then pay to have the furnace & ducts cleaned. They have a new mud product which reduces the sanding time, I'm going to investigate. Then again it probably depends who is applying the mud! LOL!

[aplumma]

Too small of an image Art too see it well. I was hoping you would have chimed in earlier for Worm Dunker. When I said pressure remains constant throughout a system what I didn't say was if your line diameters size is reduced throughout that system, I should have said "somewhat" constant. We dealt in gases as well as water in the furnaces but more gases. Something about leaving somethings to the experts as one can imagine water cooling the most important when dealing with temperatures up to 3400F.

 

Brian, what did I tell you on the phone? You go to work and they pay you, the "pro" works for you, then you pay him. 2 of the things I pay the guy for is electrical and plumbing.

 

 

As a plumber, I pay for electrical and drywall mudding. Man I hate mudding.

O come on guys everyone knows an electrician is nothing more than a plumber who had 1/2 his brain removed. lol

 

You also can click on the picture and it should open in a big window

 

Art

[wormdunker]

Thanx Art. I clicked on it & received a much larger image. Ironmaker needs new glasses! LOL! I did some reading as you & Jigger recommended. I do like those manifolds. Individual shutoffs, easy to assemble the lines, nice neat looking installation. Now you guys have me re thinking my entire plumbing job downstairs. It's OK. If I replace my 1/2" pex with 3/4" I'm out of pocket $9.00, but able to use the 1/2" piping elsewhere. The 1/2" fittings are also re usable. Thanx

[Old Ironmaker]

I always was told plumber is a urologist with 1/2 his brain removed. I assumeded you have 3/4"main feed El Wormo.