New wider pipes, lower water pressure

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Peter Rodgers

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Hi all,

I was hoping someone might have some insight into why I might be getting lower water pressure after installing wider pipes.

I replaces a section of pipe from my water tank to my house. It used to be 1 1/4" PVC that transitioned to 1" steel. I replaced with 1 1/2" PVC, hoping to reduce some of the static head loss as it's a fairly long run (roughly 150 feet). Instead of the pressure rising, I lost a good amount of pressure.

Before changing the setup, I measured about 22 PSI. Now I'm measuring about 10 PSI at the house. My tank is about 40-50 feet above main house. The reason I replaced the pipe was because I previously had a single pipe going from my well to my tank that tee'd into the house. I installed a new ozone filtering system and wanted a separate input and output from my tank.

I checked all my joints, and no leaks. Everything seems fairly solid. Is the pressure loss expected given the new setup? The 1 1/2" lines eventually join up with 1" steel pipe before entering into the house, where it is further reduced to 3/4" copper.

I would appreciate any help in trying to diagnose the cause of this problem. My thoughts are that it could be:
- some sediment blocking the line from my new work
- a gross miscalculation and misunderstanding on my part of the expected effect of pressure
- a water filter somewhere on the way to the house

Any other ideas?

Thanks in advance!
 

Terry

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The size of the pipe has no effect on pressure readings.
It does make a large difference in friction loss. A larger pipe will have less friction loss, and no change in pressure.
It does allow more water to pass through the pipe. If the pressure has dropped, something else is going on.
 

Peter Rodgers

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The size of the pipe has no effect on pressure readings.
It does make a large difference in friction loss. A larger pipe will have less friction loss, and no change in pressure.
It does allow more water to pass through the pipe. If the pressure has dropped, something else is going on.

Thanks for the response, Terry. Any thoughts on what else it could be, other than sediment clogging up the line?
 

DonL

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What kind of pump do you have ?

What is your pressure switch set at ?


Good Luck on your project.
 

LLigetfa

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Before changing the setup, I measured about 22 PSI. Now I'm measuring about 10 PSI at the house. My tank is about 40-50 feet above main house.
Assuming the tank is gravity feeding the house, then 50 feet producing 22 PSI is spot on since you get .43 PSI per foot of elevation. The laws of physics are immutable and the size of the pipe cannot change it. As Terry said, the only thing the larger pipe can do is reduce friction loss.

If you are now measuring 10 PSI when water is not flowing, then your gauge has to be lying to you. If the measurement is during flow, then there has to be a constriction somewhere.
 

DonL

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I kind of wondered if it was a gravity feed.

That ozone filtering system adds loss also.

Should not loose pressure, when everything on the output is off, but flow is restricted in them.
 

LLigetfa

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The OP does not say how the ozone filter system is plumbed but my guess is that the change in the plumbing is because it is not inline on the outflow. Ozone systems require a certain contact time so they are either flow restricted or they recirc the water in the holding tank.
 

Peter Rodgers

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What kind of pump do you have ?

What is your pressure switch set at ?


Good Luck on your project.


I'm not sure. The new line isn't directly connected to the well pump now. It's completely gravity fed from my water tank to the house.

Is it the pump that normally creates the pressure for the house? I assumed the pump just pushed water into my tank and the gravity created the remaining pressure. The well is about 150 feet below the tank, and about 100 feet below the house.
 

Peter Rodgers

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The ozone filtering isn't inline. The ozone filtering happens on input and there is a filter with ozone injection that recirculates in the water tank as well, so I don't believe it affects the output.
 

LLigetfa

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Is it the pump that normally creates the pressure for the house? I assumed the pump just pushed water into my tank and the gravity created the remaining pressure...
The pump can produce more pressure than gravity can from tank. When the pump was Teed into the line, it could have produced a small amount of boost above what gravity provided whenever the pump was running.
 

Peter Rodgers

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The pump can produce more pressure than gravity can from tank. When the pump was Teed into the line, it could have produced a small amount of boost above what gravity provided whenever the pump was running.

That makes sense.

I think what I'll do is tee off the new line before the house and check the pressure before it enters the house to see if there is any sort of blockage inside the house.

Is there a way to boost pressure from a gravity fed system, besides raising the tank or adding booster pump?
 

Peter Rodgers

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The pump can produce more pressure than gravity can from tank. When the pump was Teed into the line, it could have produced a small amount of boost above what gravity provided whenever the pump was running.

Although I did take pressure measurements when the pump was off..
 

DonL

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What kind of tank do you have ?

How does it get filled with water ?
 

Peter Rodgers

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What kind of tank do you have ?

How does it get filled with water ?

It's a 2500 gallon tank. There's a manual timer switch to turn on the pump.

Previously the pump pushed water through the bottom connector of the tank. The new setup has input coming in the top of the tank, and output remains out the bottom.
 

DonL

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Manual Timer ? I do not get it. Most timers are auto, or are You the Timer and you are turning a switch on and off ?

Where does the Water come from that fills the tank ? Is the tank vented or does it have pressure ?

I know, more questions than answers. Spit it out, to get better help.


Good Luck.
 
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Peter Rodgers

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Manual Timer ? I do not get it. Most timers are auto, or are You the Timer and you are turning a switch on and off ?

Where does the Water come from that fills the tank ? Is the tank vented or does it have pressure ?

I know, more questions than answers. Spit it out, to get better help.


Good Luck.

I'm turning a timer switch on and off. The manual part is me switching the timer switch on and off (i.e. there is no automatic filling of my water tank).

The water comes from a well pump.

The tank does not have any pressure as far as I can tell, it's just a plain water holding tank. I don't see any vents, just the manhole cover up top.

Happy to answer any more questions you might have!
 

DonL

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It needs to be vented for gravity feed.

Sounds like it is doing all it can.

You may want to put a small pump and tank if you need more pressure.


Good Luck.
 

Peter Rodgers

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It needs to be vented for gravity feed.

Sounds like it is doing all it can.

You may want to put a small pump and tank if you need more pressure.


Good Luck.

That's a good point. I'll take off the manhole cover for a bit and see if that's the cause.
 
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