Re plumbing a century home

Ok, so Im re-doing a century home. Im taking out the galvanized and going with PEX. Yes Pex!!! LOL I know nobody likes it. Here is my predicted setup. Looking for any input or advice. BTW, heater is in basement.

Have a bathroom upstairs( 2 Storey) Bath, Sink, Toilet

Main Floor Shower, Sink, Toilet
Ktchen Sink, Dishwasher
Laundry Tub, and Connections for Washer

I plan to run 3/4 Hot line to a remote manifold that will branch off that manifold with 1/2 PEX to supply upper level. Then continue the 3/4 line out of that manifold to the next manifold that will supply the hot for the main level.
Then continue that 3/4 line to return to the lower side of the gas water heater and install a recirculatiing pump. I will insulate the entire 3/4 hot line.

Hows this sound? and will it work to provide instant hot water, and save wasting water?

Thanks.

What are the distances? How far from the meter to the furthest fixture?
Who's pex are you going to use?
Whats's the incoming water pressure?
What is the total SFU for the load?

Without doing the calculations there is no way anyone is going to be able to give you a yea or nay, but I suspect that 3/4 will not be large enough.

Peter Griffin said:

What are the distances? How far from the meter to the furthest fixture?
Who's pex are you going to use?
Whats's the incoming water pressure?
What is the total SFU for the load?

Without doing the calculations there is no way anyone is going to be able to give you a yea or nay, but I suspect that 3/4 will not be large enough.

Click to expand...

Im not a pro plumber, Im not looking for yea's or nay's, and if someone asked me for assistance in my trade...I would offer input in laimons terms. As for SFU I dont even know what that is??? Square ft I guess. I will be using Wrsbro pex, the incoming pressure I have no idea, as Im not in the house yet, it closes the deal 28th Aug. The house Square ft is 1450, From the meter to the furthest fixture is the upper bathroom about 20ft max. Everything else is very close to the water heater directly above it, max 10 - 15 ft. I will have a total of about 25ft Max of 3/4 coming off and returning to the water heater. All Im asking for is ideas, or things I might want to concider or implement. If I was a plumber, I would,nt be asking for help.

The ID of pex is smaller than the equivalent of copper. Now, you usually have fewer elbows and other connections when using pex, so depending on the distance the water travels, and how many things it goes through (a manifold doesn't help), you may have enough restrictions in that you'd notice the difference.

If say in the tub or shower, it is a large tub or multiple showerheads, you may want to use 1" to the manifolds, and 3/4" to those valves, and 1/2" to the remaining things like the sinks and toilets.

design

If I understand your routing properly, all you will gain by going to the upper level first and ending up at the lower level will be using a lot more tubing.

I think Peter did a pretty god job of explaining the process. You can't just "close enough" a project like this and expect to get good results. SFU is supply fixture units and refers to the maximum water flow at the various fixtures. You need to know that and you need to know the incoming water pressure. You also need distances from meter or mains to branch fixtures to do a proper job. Plumbers would take all that information and hit the books so to speak, before changing things. JAD, is also correct in that Pex does not flow like copper and generally must be upsized to provide proper flow. All you need for info should be in the appendix section of your state code book under Sizing the water supply.

Do it right or do it twice.

I think I might be confusing you. All of the 3/4 supply line will be in the basement. There will be 2 Manifolds in the basement Both 1" Manifolds. One will be 10' from the heater, the other will be almost directly above the heater close to the joist. The first 1" manifold will supply only the upper level bathroom "hot" ( its a 4 port manifold of which only 2 ports will be used ) that will allow me 2 spare ports. The 1/2 pex will come off this manifold and travel aprox 14 -16 direct, with no elbows or connections straight up to the upper bath tub and a second direct 1/2 line with no connections will supply the upper level sink side hot. Then off of the first ports open end the 3/4 line will continue just above the water heater about 10ft max to the next manifold. This will also be a 1" manifold with eight 1/2 pex outlets that will supply the lower level fixtures. They will all be direct, no connector 1/2 pex to each fixtures hot. The longest being maybe 15', with most being under 10-12 ft. Then off the back of this 1" manifold the 3/4 will continue down to a recirculation pumpp at the return bottom of heaters water tank. Is this more clear now??? Then that way the hot water will circulate through the say 20 ft max of 3/4 line and manifolds for hot on demand. The only 1/2 lines used will all be direct relatively short lines coming off the ported 1" manifolds.
YES NO MAYBE????

You are not confusing us at all so I guess the answer is maybe. What you are purposing may or may not be good. Without running the numbers who knows. And honestly, most of us are too busy to do that for you. It's gonna take a couple hrs and a calculator.