Plumbing Suggestion Needed for Parents Home

[mlance]

View media item 883Hello,


My parents have fallen ill and unable to take care of their home. I am looking into some of the issues with the plumbing and have some questions.


Background:

• 2008 build
• Rural area on a well/septic
• 1500 sq foot, 2 story home, 2.5 baths
• Poured concrete crawl space
• Water treatment system includes
  • Pressure tank
  • Air pump to help remove sulfur smell/taste
  • Bleeder tank
  • Charcoal filter
  • Water softener
  • UV light

Problem:

The upstairs bathrooms do not get enough volume and/or pressure to them.


When I look in the basement I see post the water treatment system the following is happening:

• 3/4” copper trunk line running out from system. Goes to tankless hot water heater and the hot line (3/4”) comes back and meets beside the cold line
• Here there is a ½” tee that goes to the kitchen sink (hot and cold). This works fine
• Over a few feet there is another ½” tee for both the cold and hot. This runs over and ultimately supplies 13 devices (3 toilets, 5 sinks, 2 showers, 1 bathtub, 1 laundry machine, 1 outdoor spigot).

My question:

1. Does it make sense that the ¾” trunk line tees to a ½” line that runs through the rest of the house? I would have thought there should be multiple tees off of the trunk line instead?
2. Would it make sense for me to do the following to help fix:
   1. Use a 3/4'” x ¾” x ¾” slip tee in the cooper pipe to essentially replace the ½” tee and run a longer ¾” pex line.
   2. Tee off of this ¾” pex line in various spots where appropriate

My thought process here is to try and maximize the amount of ¾” line and minimize the amount of ½” tees that tee off of ½” lines.


Thoughts?

I attached a terrible drawing to help explain what I mean...

 

[Rossando]

You can upgrade to 1 inch pipe for supply to the main then go to water heater with 1 inch and continue on and drop to 3/4 trunks when appropriate.

 

[Diehard]

By right the proper way would be to look at anticipated loads(flows) through each section of pipe, all the way from the source to the individual fixtures. Looking at and adding pressure losses along the way. Of course you would have to look at the available codes and documents that show what the losses would be for certain flows, through certain pipe sizes and at various distances. This may be too challenging for some.

But to start with, even though it may be pretty obvious that there are many pipes that are undersized, I would look at the available pressure at the main service coming into the house. First static(no flow condition) and then with a flow taking place(dynamic) to see how much pressure loss you are getting before you even get into the house piping and equipment. Ideally, it would be good to know the flow rate during this dynamic pressure test. For example, time how long it takes to flow a couple of gallons into a bucket.

Then I would check the pressure loss through that water treatment system(pressure gauge downstream of the system). Flowing at a know or average flow rate. That would be the first place to look for excessive pressure loss. Also gives you a starting point for available pressure to the rest of the house. Then I would start looking at the distribution piping and estimating how much addition pressure loss will occur, either by calculation or by checking actual pressures at different points in the system, if possible.

 

[mlance]

Thank you for replies. I believe the problem has indeed existed since they build the house.



I put a pressure gauge on several places and got the following readings:

-feed into the pressure tank 40lbs

-pressure gauge at the tank was 40lbs

-feed out of the pressure tank 40lbs

-Outside hose bibs (opposite sides of hose) both at 40lbs



It is a Red Lion RL20 captive air tank (20gallons). The tank doesn’t turn on noticeably fast after running the faucets.

 

[Diehard]

It sounds like you took static (no flow) pressure readings.
There would be no difference at different locations if there is no flow.

There's the beginning of your problem, low pressure at the source. Turn up you pressure setting a bit.

 

[mlance]

What is an ideal pressure setting?

 

[mlance]

So I turned the pressure tank up to 50lbs. Then I went and put a pressure gauge on an outdoor hose bib. It measured at 50lbs. Then I turned the kitchen faucet on and the hose bib dropped to 40 lbs. then turned on a bathroom faucet and it dropped further to 25lbs, then I did an upstairs faucet and it dropped to about 10lbs

 

[Diehard]

Well first off the pressure switch setting and on/off operation is typically about 20 psi differential. For example, turns ON when it drops to 40 and OFF when it reaches 60 psi. The actual requirement could depend a bit on application. e.g.-number of stories. Each story could account for 3.5 to 4 psi pressure loss. That's completely independent of pipe sizes and subsequent friction loss. Or excessive pressure drop in system.
Not familiar with the typical pressure switch but I suspect one setting may be for either starting or stopping the pump while the other for the differential (typically 20 psi.) In other words pressure could vary by about 20 psi just based on pump operation alone.

Now based on your comments, I'm not totally sure if you left each location flowing when you tested different fixtures or whether you shut the previous fixture off. It sounds like you may have left the previous fixtures running, which would increase the total flow through the common pipe serving those locations, thereby increasing the pressure loss. It's not just the common pipe but also anything in that common line, such as the water treatment system. (It didn't matter where those added flows were located, only that there flows were added to the total flow going through a common line, that happens to have a pressure gauge on it.)
The added friction loss due to the pipe size and distance can be calculated but the loss trough the water treatment items cannot. That should be tested separately as previously mention. "...check the pressure loss through that water treatment system(pressure gauge downstream of the system)...." at different and relevant flows.

EDIT: Not even knowing what your test flows were, the pressure drop value sounds too high for typical flow rate from 3 sink faucets. And I believe we're probably talking about a 3/4" line.

 

[frodo]

Problem:

The upstairs bathrooms do not get enough volume and/or pressure to them.




Over a few feet there is another ½” tee for both the cold and hot. This runs over and ultimately supplies 13 devices (3 toilets, 5 sinks, 2 showers, 1 bathtub, 1 laundry machine, 1 outdoor spigot) .

problem is the water piping is woefully undersized.

you should have a 3/4 line run with 1/2 branches to ONE fixture only

read this

https://codes.iccsafe.org/content/IPC2018/chapter-6-water-supply-and-distribution

Sizing plumbing piping systems is not a difficult task when you have the resources to calculate the correct size pipe. The International Plumbing Code (IPC) includes a variety of charts to assist you to properly size plumbing piping systems. Once you understand how to use these charts, you can quickly complete uniform and easily built plumbing systems in buildings. There are three steps to calculating the proper size for a plumbing piping system:



https://codes.iccsafe.org/content/IPC2018/appendix-e-sizing-of-water-piping-system



Add up the total number of water supply fixture units (wsfu) required in the facility

Estimate demand using the table from the IPC that correlates wsfu to expected demand

Size the pipe using demand vs. friction loss curves found in the IPC charts

Following is an explanation of each of these steps and instructions on using the related IPC charts.



The wsfu values for typical plumbing fixtures are listed on IPC table E103.3(2) (Figure 1). Locate the type of fixtures to be used in the facility and then add up the total wsfu values for all plumbing fixtures being served. Find the number closest to the wsfu value on Table E103.3(3) (Figure 2) to estimate system demand in gallons per minute (gpm). Because the chart includes the supply required for both flush tanks and flush valves, you must determine if the system is predominantly one or the other, bearing in mind that most commercial jobs will be flush valve. Most likely, the number you calculated in step one is in between wsfu values found in the second chart. This means you will have to Interpolate to find demand, which will be illustrated in the upcoming example. Finally, IPC Chart E103.3(6) (figure 3) enables you to determine the pipe size using the appropriate demand vs. friction loss curves.



The following example illustrates how all of this works. Let’s assume you are assigned to determine the domestic cold water for a public bathroom with four flush valve water closets and two lavatories. You can tell by using the IPC chart (see figure 1) that the wsfu values are 10 for the water closets and 1.5 each for the lavatories. The total wsfu required is calculated like this:



WCs: 4 X 10 wsfu = 40 wsfu

2 Lavs: 2 X 1.5 wsfu = 3 wsfu

Total wsfu: 40 + 3 = 43



When you look for this number on the Table for Estimating Demand, (Figure 2), you see that the total wsfu of 43 falls in between to listed loads: 40 and 45. This is where it is necessary to interpolate the actual demand. To accomplish this, use a formula that determines the difference between the two load amounts and the related gpm’s. In our example, it would look like this:



=48−(48−46)∗(45−43)(45−40) =47.2 gpm



Finally, you turn to “Friction Loss in Fairly Rough Pipe” table (figure 3) to determine the proper size pipe for the application in our example. Assuming a maximum velocity of eight feet per second (fps), we will plot on the graph where our demand (47.2) meets this velocity. From that point, you select the nearest pipe size to the left of the 8 fps velocity curve. In this example, you will select a two inch pipe. If you want to know the pressure drop, calculate it by reading the friction loss from the bottom of the chart.



Now that you have seen how to use the IPC charts and tables, you are ready to quickly and accurately size plumbing piping systems.[/QUOTE]

 

[frodo]

if you run a pex line instead of a copper line
you will need to run a 1'' pex line
goggle the inside diameter difference between copper and pex
1/2'' pex is actually like 3/8 copper
3/4 pex is like 1/2''
so if using pex, run a 1'' trunk. branch off using 3/4
then reduce to 1/2'' when you stub out of the wall

 

[frodo]

What is an ideal pressure setting?

fiddy psi

 

[mlance]

Thanks for all the replies.

The pressure tank to the water treatment system and ultimately to the hot what heater is all 3/4” copper. I wanted to tee into that so I don’t have to replace all that copper.

Can I leave all of that and where it tees to 1/2” just switch there to 3/4 pex and eventually branch at 1/2? I assume I cant tee to 1” pex from 3/4 copper?

 

[frodo]

cut a 3/4 tee into the copper line
then install a 1x3/4 reducer
transition to pex

 

[Diehard]

It's fairly obvious that your distribution piping sizes are in need of improvement.

However, I would strongly suggest you find out what you have available for flow and pressure, immediately before and after your Water Treatment System. As that is what you should be using as a basis for your distribution piping design criteria, and how much pressure you'll have available at each demand.

Even if you don't get into the detail design exercise as explained in the codes, etc. you should look at what is happening for flow and pressure at the start of your system.

BTW...When you took your pressure readings at the outdoor hose bib, and the pressure readings dropped from 50 psi to 10 psi you obviously had all 3 faucets open at that point. Please confirm to make sure I completely understood you.
Because if that's true, and that outdoor hose bib was off the main 3/4" line as I show in my sketch, you certainly have a little mmore going on then just some undersized distribution piping and should know about it first.

Also, when and if you do get into calculating the ideal PEX tubing size, you can find pressure loss values for the actual PEX tubing vs copper piping.

 

[mlance]

Yes I had all faucets open when I was testing

 

[frodo]

Yes I had all faucets open when I was testing

that is good, look at the charts i provided
the system design criteria is that you have enough water and pressure at each fixture if the whole system is on

 

[Diehard]

Yes I had all faucets open when I was testing

Now...understand that 40 psi loss happened, not in the distribution piping to those fixtures, but between your main service and the point where the branch for that outside hose bib is located.
Think about that a bit.

 

[frodo]

with everything on
measure gpm and psi at each fixture
compare it to this chart

 

[Diehard]

I believe the OP already knows that there is inadequate flow and pressure so I suppose he may like to know how inadequate.

I believe taking a logical approach and starting with finding out what he has to work with first, then he can look at the codes recommended pipe sizing for various fixtures, etc.
One should know how much pressure is available before sizing for friction loss.

To be honest, I doubt the average person, with little to no feel for this stuff, will go through trying to calculate required pipe sizes by the book but if they do, they should at least take the logical path in getting there.

 

[mlance]

I am not sure the hose bib I tested on was before or after the fixtures. It would have been for sure after the kitchen and the main floor bathroom but before the upstairs bathroom.

I would agree I don’t understand everything I am reading but I struggle to understand why the 3/4 copper line has one pex 1/2 tee that the entire house runs off of (except kitchen) and it is a 2 story hose.

To me it seems like I should at least start but removing the tee and putting in a 3/4 or 1” pex line that then has separate 1/2 tees for all fixtures. Maybe this doesn’t fix my problem but it seems low cost, writhing my skill set and likely can’t make it worse? Am I wrong on my thinking?