Need to add 40' of length, reduce pressure?

[ctwilliams]

Hi...

We will be adding a water softener to our house and due to its location we will need to add approximately 20' of 1" pex from the pressure tank to the water softener and then another 20' to get back to where the lines split for hot and cold water.

Will the addition of the 40' of 1" pipe reduce water pressure any noticeable extent? Or, should I move things around to eliminate having the additional 40'?

Line coming from the well to the pressure tank is 1" and is about 90' long.

Thanks for any thoughts...

CT

 

[SlowDrip]

Well, to get a true calculation of friction loss we need a bit more info. There are four factors to consider and you have given us two.

We need the pipe diameter and the length, which you have provided, but we also need the water velocity and the "C" rating of the pipe (the hazen-williams roughness constant).

The formula is:

f = 0.2083 (100/c)1.852 q1.852 / dh4.8655

where

f = friction head loss in feet of water per 100 feet of pipe (fth20/100 ft pipe)

c = Hazen-Williams roughness constant

q = volume flow (gal/min)

dh = inside hydraulic diameter (inches)


Elevation wise, fresh water loses .433 psi per foot of head.

 

[lma1]

Hi...

We will be adding a water softener to our house and due to its location we will need to add approximately 20' of 1" pex from the pressure tank to the water softener and then another 20' to get back to where the lines split for hot and cold water.

Will the addition of the 40' of 1" pipe reduce water pressure any noticeable extent? Or, should I move things around to eliminate having the additional 40'?

Line coming from the well to the pressure tank is 1" and is about 90' long.

Thanks for any thoughts...

CT

Another useful form of the formula is:

P = [4.52 x Q(superscript 1.85)]/[C(superscipt 1.85) x d(superscript 4.87)]​

Where:

P = Frictional resistance, PSI/ft of pipe
d = Actual inside diameter. in.
C = c as explained by SlowDrip, roughly 150 for any listed plastic pipe
Q= q as explained by SlowDrip.

 

[ctwilliams]

Thanks for the replies....For determining the flow rate, since the only outlet I have is at the well (the one on the pressure tank is next to the floor/wall and I can not get to it, will that be sufficient even though it will not take into account the length of pipe into the house?

 

[Mr_David]

You can twist you panties in a knot trying to figure out the Calculation but If you are using a 1" pipe you probably wont notice much of a change.

 

[speedbump]

You can twist you panties in a knot trying to figure out the Calculation but If you are using a 1" pipe you probably wont notice much of a change.

I agree. Most homes have 1" to the tank and 3/4" from there to the softener and on to the faucets. So with the one inch, you probably won't notice a bit of difference. However the softener will offer quite a bit of resistance to flow which will effect pressure. On average a standard softener (a unit with 1 cu ft) of resin in it (not fine mesh resin) will drop pressure somewhere in the 10 psi range. Give or take a few pounds.

 

[Mr_David]

Good Call SpeedBump.
I'm not to familar with well systems but can the supply pressure be increased at the pump to offset the end result at the house

 

[SlowDrip]

Depends on the pump setup, David. Shallow well pumps are a lot easier to work with than deep well pumps.

The only reason i didn't say "meh 40 ft of pipe is fine" like I would in a city-water supplied house is that a lot of deep well pumps are chosen incorrectly and work near the outer limit of their capacity. People guesstimate the depth of the well and the length to the house, then buy the cheapest (read smallest) pump that will do the job.

 

[speedbump]

If the pump will allow, he could jack up the pressure switch and try to get back close to where it was before the softener. He never said if he has a jet or sub, shallow or deep, so it's hard to say without more info.

 

[user 1231]

I agree with Mr. David. Without having to do a lot of calculations, 1" water piping over 40' with no appreciable rise will not result in a significant loss of pressure. That being said as speedbump mentioned the unit with 1 cubic foot of resin will result in 8-12 psi of drop. If you change the pressure switch out to a 40-60 or even higher pressure unit or alter the settings on a standard pressure switch it should help somewhat, but keep in mind that it might be beneficial to put a booster pump and holding tank on the other side of the softener, instead of messing around with the factory settings on a pressure switch.

 

[speedbump]

but keep in mind that it might be beneficial to put a booster pump and holding tank on the other side of the softener,

Remember that when adding a booster pump, its pressure capabilities are added to the standard systems pressure. So in a 40/60 standard system, if you add a centrifugal pump that can make 50 psi, that could add up to 110 psi. This could be a problem.

 

[ctwilliams]

If the pump will allow, he could jack up the pressure switch and try to get back close to where it was before the softener. He never said if he has a jet or sub, shallow or deep, so it's hard to say without more info.

Guys, thanks for the suggestions. I had not thought of turning the pressure up to compensate.

The well is 780' deep and has a Goulds 4" submersible pump model 7GS. The GPM rating on the well is about 8 or so.

I take it my next step should be to determine what the pressures are set to now and then I will know if I can up them to cover the loss from the water softener.

We have a three story house, what would be a safe setting for the on and off pressures?

The guys are coming out this Wednesday to install it, so we will see how it goes.

 

[speedbump]

I wouldn't go above 75 psi for the top pressure.

 

[ctwilliams]

I wouldn't go above 75 psi for the top pressure.

The pressure is now set to 36/60.

After watching the gauge I found that that the pump is only running about 20-30 seconds to fill the pressure tank back to the 60psi. I thought that these pumps needed to run longer so they were not "short cycled" and reduce the life of the pump.

Is there anything I can do about this?

I watched it again as two showers were running at the same time and it took it about 1.5 minutes to get up to the 60 psi. I assume that length of time is long enough.

I will adjust the pump up to about 70 or so. Should I adjust the pump turn on pressure up as well or stick at 36?

Thanks, learning a lot.
CT

 

[user 1231]

Hey CT,

I agree with speedbump, do not go over 75psi as that is what prv valves for city water max at. I like to set mine around 45-65 and unless you have a shower with multiple bodysprays and heads that should be fine. Also consider adding a larger bladder tank. Most "builder" houses around raleigh come with 20 gallon pressure tank and if you are irrigating that is never enough. Speedbump, in adressing your concerns i usually run the main water into a large holding tank that is non pressurized, with its own shutoff. That is the water i supply the pump with. It is really just a reservoir. I agree, having both pumps pushing would be risky. Thanks for making me be more precise. Sometimes it is hard to remember that if i am speaking to a non professional or even a pro we all have different way of doing things and we need to be precise so we do not cause more problems than we fix.

 

[speedbump]

i usually run the main water into a large holding tank that is non pressurized, with its own shutoff. That is the water i supply the pump with. It is really just a reservoir.

I work with people a lot with these types of systems or help them set one up. Usually in areas where the wells don't make enough volume to keep up with normal household usage. They can put the well pump on a timer to take advantage of what they can get from the well without running the pump dry. Then use another sub in the storage tank to pressurize the home.

 

[ctwilliams]

Well, the system was installed on Wednesday and I have some concerns about how they ran the piping. They did use 1" pex which is the same as we had when the house was built. The area of the install is not finished and is wide open. The original plumbers used as few 90 or 45 degree connectors when running the pipe and just used the flexibility of the pipe and gradually (in terms of radius) made the turns required.

The water softener installers instead used a total of six 90 degree connectors when they ran this new loop. It appears to me that it could have been made with none or possibly two if the radius was too tight.

We have noticed a reduction in water pressure, especially on the third floor.

So my question is, do the 90s need to be removed as they cause way to much restriction or is the pressure drop we see due to the water softener itself?

Thanks...

 

[speedbump]

Both, but mostly from the softener. The elbows aren't helping any though.