Common Pressure Switches

[Bubba]

Why are 40/60 and 50/70 pressure switches so common in residential applications?

If you buy the appropriate pump with required volume and pressure, why not always go to a higher pressure switch (say 60/80 or 70/90) for a 2 storey, modern house?

 

[Reach4]

Higher pressure has some downsides, but not big bad things. Water hammer would tend to be more if it happens. Pressures on washer hoses could increase failure rate, but I don't know of a study along those lines.

Fixtures and softeners are designed to work with 30 psi or more. They are usually rated for 80 psi max working pressure which codes call for, although pressures over 100 are normal due to thermal expansion even with a thermal expansion tank. Those elevated pressures drop down when you start using some water. People with city water and need a pressure reducing valve usually have those set to about 50 to 60.

You get slightly more drawdown on a pressure tank on a 40/60 than a 50/70 system. Small effect which could be more than compensated for with a bigger pressure tank.

On the plus side, higher pressures operate some irrigation heads better.

 

[Sponsor]

 

[Valveman]

Why are 40/60 and 50/70 pressure switches so common in residential applications?

If you buy the appropriate pump with required volume and pressure, why not always go to a higher pressure switch (say 60/80 or 70/90) for a 2 storey, modern house?

You can have as much pressure as you want. I hate it when people say they want "city like" pressure. It is your pump system, you can make it do whatever you want. As was said, there are downsides to too much pressure in a house. I actually have a little 1/2" ball valve on my shower head as sometimes 50 PSI constant will try to gouge my eyeballs out of the sockets. Lol! But I like strong constant pressure in the shower. If I step out of the way it pressure washes the grout on the back wall.

All kidding aside, sometimes the pressure switch needs to be set higher because the house is higher up on a hill or something. I set one recently at 130/150 that will supply 40/60 and constant 50 to a house on top of a 200' tall hill. I have set them as high as 380/400 to supply 40/60 to a city on top of a 780' tall mountain. High rise buildings, same thing.

 

[Bubba]

I doubt that I've ever been in a cottage with a system that was well designed with plenty of flow, so I don't have a feel for what constant 50 psi or 60 psi is like in a shower. So if I put in a good system with say a 50/70 switch and CSV set to 60 psi in the basement, even 2 stories above I'll have constant 50+ psi.

It sounds like you're saying that's all the pressure most people would ever need for powerful showers, etc.

 

[Fitter30]

50 lbs of water pressure on a first floor, 12' above would only drop the pressure 5 lbs

 

[Valveman]

I doubt that I've ever been in a cottage with a system that was well designed with plenty of flow, so I don't have a feel for what constant 50 psi or 60 psi is like in a shower. So if I put in a good system with say a 50/70 switch and CSV set to 60 psi in the basement, even 2 stories above I'll have constant 50+ psi.

It sounds like you're saying that's all the pressure most people would ever need for powerful showers, etc.

So, if you have large pipes all the way to the shower and drill out the restrictive orifice in the shower head, 30 PSI will make for a strong shower. However, if the shower head is restrictive, or you have long lengths of small pipe before the shower, you need more pressure to get a good shower. If you have 30 PSI of friction loss and restriction before the shower, bumping the well pump pressure up to 60 will still get you a strong shower.

50/70 with 60 PSI constant from a Cycle Stop Valve is what I use with a second story on the house and .

 

[Bubba]

So, if you have large pipes all the way to the shower and drill out the restrictive orifice in the shower head, 30 PSI will make for a strong shower. However, if the shower head is restrictive, or you have long lengths of small pipe before the shower, you need more pressure to get a good shower. If you have 30 PSI of friction loss and restriction before the shower, bumping the well pump pressure up to 60 will still get you a strong shower.

50/70 with 60 PSI constant from a Cycle Stop Valve is what I use with a second story on the house and .

OK great, thanks.

 

[LLigetfa]

Why are 40/60 and 50/70 pressure switches so common in residential applications?

The manufacturer does not know what pressure may deadhead the pump and their lawyers probably advised not to sell them with higher presets. OF course, since they are just presets, you could turn them up but then you assume full responsibility.