Installation of pressure regulators can be accomplished in a relatively simple way. Although installation and the use of regulators might be simple, some problems do occur. For example, when you select 10-PSI pressure regulator, you might not actually be receiving the amount you called for. The pressure may be higher then 10 PSI for low flow regulators and lower for high flow regulators.
The reason for this situation is due to the fact that if the pressure has been high and is decreasing, the outlet pressure may be 0.5 PSI higher then if the pressure had been increasing. Therefore, the outlet pressure for a 10-PSI square pressure regulator could have a value ranging from 10.6 PSI to 8.9 PSI. This may not be a problem but one must be aware that if it exists when designing an irrigation system.
Flow is also important when selecting a pressure regulator. Regulators have a recommended range of flows (gallons/minutes). If a pressure regulator is outside its recommended flow range, it will create poor regulation, high-pressure losses, or both.
Most household water pressure are anywhere between 40 PSI to 90 PSI, with some homes even higher. Typically homes will have a pressure regulator (before the water goes to the pipe inside the house that is set at 40 to 60 PSI). Drip systems are designed to work at an even lower pressure; the optimal pressure for a drip system is between 20 to 30 PSI and for drip tape is 10 to 25 PSI. If higher pressure allow to the system, a problem will accrue with the drippers, drip tape, micro sprinklers and the fittings such as drippers popping off, higher flow for the drippers and micro sprinkler and components blowing out of the drip tubing. In a layout for a large system, we may need a higher pressure. This is most common for a single long lateral or when using PVC pipe as the main line to delver the water to many long length laterals. In this type of application the system will experience a pressure drop and low uniformity between the drippers or micro sprinklers due to the long run of the drip laterals. To make sure that the uniformity is kept along the line a drip system should have a minimum of 15 PSI at the of the line a micro sprinkler should have a 25 PSI and a drip tape 10 PSI. To accomplish the minimum pressure at the lateral end a higher pressure regulator or adjustable pressure regulator may be required.