Plumbing Suggestion Needed for Parents Home

you are correct
1/2'' copper pipe at 40 psi only delivers 14 gallons per minute
3/4 delivers 26 gpm
3 terlets require 1.6 gpm = 4.6 gpm and you have other **** hooked up
5 sinks @ .8 per =4 gpm
2 showers @ 2.5 gpm= 5 gpm
1 tub @ =4
1 laundry machine =4
hose bib = 5 gpm
total is 26.6 gpm you need
a 3/4 pipe is 26 gpm
you need the 1''

bottom line. the 1/2'' is way way way undersized and needs to be removed
and repiped correctly

abandon the 1/2 '' line and repipe the system with a 1'' trunk
run 3/4 to the fixtures.

i guarantee your problem will disappear

My challenge with that is accessibility. That would require ripping out drywall and fishing pex through walls and ceilings. I am afraid it would get messy quick.

So unfortunately I can’t do it “right”, but I think I can do it “less wrong” and at the least see marginal improvement. Here are my options I suppose

Option 1)
Run a 1” pex line from water system to the water heater and back as hot. Here tee off with 1” hot and cold lines and then connect into each existing 1/2 fixture run separately

Option 2)
Leave existing 3/4 copper. Replace the existing 1/2 tees for hot and cold with 1” pex. Run the 1” lines and then connect into each existing 1/2 run separately

Option 3)
Same as 2 but use 3/4 pex instead of 1”. Only an option as I don’t understand if it is okay to go from 3/4 copper to 1” pex...

You are not wrong in your thinking!

Just taking a different approach.

Would be nice to know where that pressure reading was taken relative to the the flows. Oh well.
Best of luck!

.

frodo said:

you are correct
1/2'' copper pipe at 40 psi only delivers 14 gallons per minute
3/4 delivers 26 gpm
3 terlets require 1.6 gpm = 4.6 gpm and you have other **** hooked up
5 sinks @ .8 per =4 gpm
2 showers @ 2.5 gpm= 5 gpm
1 tub @ =4
1 laundry machine =4
hose bib = 5 gpm
total is 26.6 gpm you need
a 3/4 pipe is 26 gpm
you need the 1''

bottom line. the 1/2'' is way way way undersized and needs to be removed
and repiped correctly

abandon the 1/2 '' line and repipe the system with a 1'' trunk
run 3/4 to the fixtures.

i guarantee your problem will disappear

Click to expand...

I bite my tongue!

Pressure reading was taken from an exterior hose bib that was certainly towards the end of the line. Pretty sure most if not all the fixtures are upstream of it.

Was also wondering if it is a problem that the 3/4 copper runs from the water system and tees off to kitchen sink and also to the 1/2 inch tee I am talking about AND continues to the hot water tankless system (in that order). The 3/4 copper then continues back as hot water to the kitchen since and to meet up with the other 1/2 tee to run beside the cold.

Seems like that might also starve the hot water system if other fixtures are running cold.

So now my thought is to do this:

1) after the water system put a manifold in (by manifold I mean the 3/4 in/out with multiple 1/2 branches
2) connect the existing 3/4 copper line to it and have it feed the kitchen and hot water system as is
3) remove the 1/2 cold water tee coming from the copper (the one that branches off and I have been concerned about)
4) from the manifold, run home run lines to connect to the existing 1/2 lines. Wouldn’t be true home run lines but basically to all lines before they go up into the walls
5) meanwhile for the hot lines, add another manifold after the hot water system and do the same thing and run individual hot lines to marry up with the cold lines wherever possible

I know I am all over the map here and I appreciate all the input! My apologies for “thinking out loud here”. Just want to help my parents especially during this tough time and want to do it as best as possible.

Does this approach make sense? Or should I stick with previous options?

Generally an exterior hose bib gets taken off the piping system in the basement level. Or it may get taken off in the walls from the piping going up to the first floor demands. I doubt the flow travels through the majority of the distribution system before it reaches the point where it tees off for the hose bib.

If you are talking about doing whatever work you can do in the basement, to improve the situation, sketch out all the piping in the basement to the point of where it goes up stairs. Based on your sketch, I take it that it branches from a 3/4" CW line to a 1/2" line for the kitchen and a separate 1/2" line from the 3/4" CW to upstairs for every thing else. And the same for the HW lines.
Do you have 1/2" lines teeing off of 1/2" lines in the basement?

Just sketch what you have in the basement to the point of going up and leaving the basement. Just single lines for piping will do.
Are you able to see all the piping in the basement?

Your item 1) above indicates you have multiple 1/2" branches.??

EDIT: I take it you cannot get pressure readings before and after you Water Treatment system?? Do you have a pressure gauge at the pressure tank somewhere?
Without a pressure loss reading through that Water Treatment System you are only looking at, and trying to solve, a piece of the puzzle.

EDIT: BTW...Many of the tankless water heaters have a fair amount of pressure loss.

See attached for newer pictures of the current and planned layouts

Nice layouts!
First off it appears, based on your description of where the test hose bib was located, that it was the one shown on the far left of your dwg. The other being taken off right after the Water Treatment System(WTS). When you have time the hose bib at the WTS shown be tested at various flow. Wouldn't matter where the flows were taken but would be beneficial to know the flow rate corresponding to the pressure, if you could manage that. Just another piece to the puzzle.

Looking at what you had already stated on pressure readings as you added flows from various locations, I approximated the flow rates based on the types of fixtures you used and approximated pipe lengths rather on the long side, for the purpose of estimated pressure losses.

Findings:
For the first flow of the Kitchen sink shows the pressure loss through the 3/4" from the WTS to the point where it tees off with the 1/2" line. I assumed 50 feet of 3/4" pipe at a 4 gpm flow. That only amounts to approx. 1.25 psi pressure loss. So that 10 psi loss your gauge showed included the added losses of the WTS. About 9 psi.

When I looked at adding the 2nd flow(say about 3 gpm from the 1st floor bathroom) and added pipe length losses due to the added 1/2" piping it totaled about 3 or 4 psi, while your gauge had shown an additional 15 psi. So at the slightly higher flow rate the WTS accounted for an additional 11 or 12 psi losses. I have to run right now but you get the picture so far?

I returned...So with that 3rd flow added(say about 3 gpm for that upstairs sink) that could account for friction loss up to about 10 psi or so depending on pipe lengths, while again the gauge went down another 15 psi(didn't travel through any additional piping). Only added flow to a section of the 1/2" and a section of the 3/4".
So roughly speaking the WTS accounted for about a total of 30 psi at the total flow rate of about 9 to 10 gpm.

Putting a gauge on that other hose bib would be a much better indication of actual pressure loss through that WTS at a given flow. Little to no piping involved for friction loss, between WTS and tee for hose bib pipe.

You would definitely benefit from dedicated 3/4" HW and CW lines for the those upstairs fixtures.
Don't think you really need 2 separate CW lines for the 1st floor toilet and bathroom sink.

Why is that proposed 3/4" line to the CW manifold shown on the opposite side of the WTS? Wouldn't that be coming off the same 3/4" line already shown as existing?

Correct it would be post WTS, just the way I did the diagram to make the picture less complicated looking