"What does 'DIFFERENTIAL PRESSURE P1 - P2 (psi)' mean?"
P1 is the unregulated inlet pressure and P2 is the regulated outlet pressure. The differential between these two numbers will indicate which column to use to determine which valve is right for you.

"What does 'P2 Variation (Pressure Drop)' mean?"
P2 pressure Variation (Pressure Drop) is the amount of desired pressure loss for the required gpm (gallons per minute) flow rate required. For example: If the differential pressure is 25 psi, the required flow rate is 15 gpm and maximum pressure drop allowed is 10 psi. The valve size needed using the chart above would be 1"

"What is water hammer?"
Water hammer occurs a lot! It is frequently recognized by a "thump" or "bang", usually throughout the water line (if you have copper pipes, you'll tend to hear the noise throughout the house). Water hammer can be caused by a number of things. Many times a loose washer that is jumping around in the faucet or valve causes it. This can be fixed by identifying which valve is the culprit and fixing the washer. Other times it is simply caused by water traveling at a rapid rate and suddenly being shut off. The best solution for this is to increase the size of the water supply thereby slowing down the water (a larger pipe being able to deliver the same amount of water in gallons per minute at a slower speed). If this is not possible, then many times a water hammer arrestor helps.

"Your water pressure regulators are factory set at 45psi. What is the full range?"
The water pressure regulators that we sell can be adjusted from 10psi up to 70psi. They can handle up to 300psi incoming pressure. We normally recommend keeping the adjustment between 40psi and 55psi for most households. We do not recommend using these regulators for applications less than 20psi. If you need your pressure lower than 20psi then we would recommend contacting a regulator manufacturer for your specific requirements.

"I need to attach a water pressure regulator to copper pipe. Do you offer copper sweat style pressure regulators?"
No, but you can use the EB86U with male copper pipe adapters.

"My inlet pressure varies, which reading should I use, the higher or lower number?"
Always use the lowest number, this will assure you of meeting your minimum pressure and flow rate requirements.

"In the example above you chose a 1" valve when a 3/4" valve almost meets the requirements?"
It is best when sizing for optimal performance that, if the requirements fall between an indicated size, you should choose the larger valve.

"Will these valves also control/limit the gpm flow rate?"
No, you will need a flow regulator to control the flow rate.

We hope that we have helped you on this page with water pressure regulators,
and thank you for helping to make PlumbingSupply.com the most famous Internet plumbing supplier.