How to increase water pressure/flow in showerheads

[CindyJ]

1/2" cpvc is too small for any but very short runs.

How long or short is a "short run?"

[CindyJ]

We had a deadly combination of low pH and copper piping, and after 35+ years, pinhole leaks developed. We had never had our water treated for low pH because we didn't know it was problematic. The first leak caused over $3,000 in damage. Since we had no way of knowing how extensive the leaking problem was, or where other leaks might (or already had) develop(ed), we decided to replace all of the piping.

We did consider PEX, but (and this will probably sound like a copout) the repipe project was something my husband was handling, and for reasons I can't recall at the moment, the decision was made to go with CPVC.

[CindyJ]

With a pressure switch turning the pump on at 40 and off at 60, shower pressure will never be very good. Installing a CSV could make the system maintain 55 PSI constant. That would seem like so much stronger pressure in the shower, that you almost no longer need soap (lol). Also if the pump is cycling on and off while the heat pump is running, as I am sure it is, you need a CSV to keep from burning up your pump/motor on a regular basis.

Given what I now know is a reduced flow owing to the replacement of copper piping with CPVC, would a CSV be safe to use with 1/2" CPVC?

[CindyJ]

I suspect the basic problem relates to your pipe replacement. Based on inside diameter, you need to upsize CPVC by one nominal size to equate to copper. In other words, replace 1/2" copper with 3/4 CPVC, replace 3/4 with 1", etc. 1/2" cpvc is too small for any but very short runs.

...and another question: We're about to replace all of the old toilets in the house with Toto Ultramax II. Will the reduction in water pressure affect the flushing capability of the new toilets?

[cacher_chick]

It will not matter, because all of the water used when flushing comes from the toilet's tank.

[LLigetfa]

Most toilets do not rely on water pressure to flush, only gravity.

Have you done the flow measurements into a bucket as I suggested? It is premature to talk about pipe size if the shower valve is the limiting factor. Pipe size affects pressure only relative to flow. Right now, I suspect the shower head is the limiting factor.

Have you taken elevation into consideration? How much elevation difference is there between where the pump pressure switch is and where the shower head is? You can count on .43 PSI loss for every foot of elevation.

[jimbo]

Thank you for the feedback.... you do have the relatively uncommon, but the one situation ( low ph) where copper has problems. Doing a repipe with the relatively unflexible CPVC must have been a chore.

[jadnashua]

FWIW, both CPVC and PEX have a lower flow capacity verses copper based on the same nominal size. This is because the outside of the pipe is what is controlled, not the inside, so because the plastic pipes need more strength, their walls are thicker, thus, the ID is smaller.

What would have worked better was to have 3/4" pipe running to the shower, then converting to 1/2" (which is probably the valve's inlet size, although some are 3/4" or even larger). Most things can function fine on 1/2", but high flow or multiple fixtures off one line need a larger supply coming into the area, then branching off with smaller pipes, where appropriate. If they ran 1/2" to the bathroom group, you'll find a real issue if someone flushes the toilet or tries to run the vanity sink while you're in the shower!

[Hackneyplumbing]

We have our own well and the pressure cycles between 40 and 60 PSI.

I would rather see a static pressure of around 75psi and no higher than 80psi.

[LLigetfa]

I would rather see a static pressure of around 75psi and no higher than 80psi.

With the pressure switch adjusted to 60/80 and a CSV properly dialed in, the OP could see just that.

[cacher_chick]

40-60 does a fine job with the right shower head. I would speculate that the majority of homes in the U.S. have less than 60 psi.

[Hackneyplumbing]

40-60 does a fine job with the right shower head. I would speculate that the majority of homes in the U.S. have less than 60 psi.

Let a guy get use to 70-80 psi and cut it back to 40-60 and you'll have complaint after complaint.

[CindyJ]

The specs for that model say it has a 5.0 GPM flow rate. Most modern shower heads are 2.5 GPM. You could capture the flow into a bucket and calculate it, then remove the head and repeat the test. That will give you some indication of how much you might gain by defeating any flow restriction in the head. It is unlikely that you can change the flow characteristics in the valve.

Okay -- I did the "bucket test." I should mention that my husband has removed the flow restrictors on both the stationary and hand-held showerheads. I ran two tests. The first one ran at 2.3 GPM, the second one was 2.5 GPM. I'm guessing that the variation was due to the cycling of the pump pressure.

So now my question is, is this more a matter of increasing the water pressure, or changing the CPVC from 1/2" to 3/4"? Or should we do both?

[CindyJ]

FWIW, both CPVC and PEX have a lower flow capacity verses copper based on the same nominal size. This is because the outside of the pipe is what is controlled, not the inside, so because the plastic pipes need more strength, their walls are thicker, thus, the ID is smaller.

What would have worked better was to have 3/4" pipe running to the shower, then converting to 1/2" (which is probably the valve's inlet size, although some are 3/4" or even larger). Most things can function fine on 1/2", but high flow or multiple fixtures off one line need a larger supply coming into the area, then branching off with smaller pipes, where appropriate. If they ran 1/2" to the bathroom group, you'll find a real issue if someone flushes the toilet or tries to run the vanity sink while you're in the shower!

I went down to the basement and the good news is that there is 3/4" pipe running from the filter to various places in the house. Or maybe it's just news, not necessarily good news because I don't know the size of the original copper pipe that was replaced with CPVC. What is still unknown is where, exactly, the 1/2" is joined to the 3/4". I do know that both bathroom showers are served with 1/2" pipe from the same split source. That, alone, is probably cause for concern.

I'm expecting my plumber here today and I'll certainly have a conversation with him about this.

[CindyJ]

I would rather see a static pressure of around 75psi and no higher than 80psi.

When you say "static pressure," does that mean a consistent water pressure as opposed to water pressure that fluctuates when the pump turns on and off?