Which Plumbing Plan?

[SeattleDave]

Attached is a PDF file containing two alternative plans for a plumbing system for a residence in Seattle under UPC-2021. All three floors of plumbing are shown on a single plan-view with floors indicated on the diagram (the only overlap of fixtures on two floors is the Pantry and Basement Laundry the former shown as an "inset". The floors are roughly 10ft high each. The two alternatives are 1) a zones-run design with 3/4" feeders to each zone within the house and 2) a loop / trunk-branch design where the hot water is looped and the cold is basically trunk and branch with the upper bathroom same in both designs for cold water. Our main interest is what will work best for equalized pressure and temperature delivery. The master bath is on its own on-demand heater and same in both designs. The loop design is simpler but we are concerned that using several fixtures at same time will affect hot water usage in the loop design. Plumbing controls (valves etc) are shown in nonstandard symbols defined at top of the pages. Also at top of page is the actual fixture units and gpm for Pex as specified by Uponor so more accurate than the typical UPC tables designed for copper. 1-1/4" meter to feed 1-1/2" pex which is same internal area as 1-1/4" copper so those are used interchangeably. Booster pump will raise to approx 80 psi.

Please give your feedback, including if its too big of a question, etc.

 

[SeattleDave]

Let me try a simpler approach and ask the experts to characterize the effect of running pipe in series vs parallel.


In other words, comparing the idea on one hand of a giant hot water loop through a house feeding all the fixtures compared to serving the same fixtures by "zone-runs" which can be thought of as running larger homeruns to various clusters of fixtures from where they are then distributed to individual fixtures. If our main concern is not losing pressure or temperature in showers while other things like washers or dishwashers or kitchen sink are running, which system will work better?

Now let's add one more wrinkle: recirculation. On the one hand the loop design is ready-made for it requiring returning to the hot water heater, a pump, and a check-valve. The zones-run design is necessarily more complex so how would that best be implemented and how well would it work in comparison?

I'd still love any feedback on the original post and the attached plans, but maybe this is easier to answer?

 

[Geofd]

Someone will give you help just be patient posters stop by all the time