Pressure Reducing Valves

A pressure reducing valve takes whatever the pump or mainline delivers and holds a steady, lower pressure on the block behind it, so every dripper, spray stake and mister in the zone runs at the pressure it was built for. The valves on this page are hydraulic control valves from Bermad, Netafim, Rivulis and Superior, in nylon and composite plastics, PVC, red brass and cast iron, from 3/4" through 16".

ML Irrigation sells them wholesale from Fountain Inn, South Carolina to production nurseries, greenhouses and horticulture education programs in all 50 states. What follows is how we sort out the right type before anyone asks for pricing.

Which type of pressure reducing valve does the block need?

Start with where the valve sits. Greenhouse and nursery zones mostly land at 1½" and 2", and three of the four lines here have a plastic body in that size: Bermad's IR-220 and IR-22T Top Pilot, Netafim's Series 75 and Series 80, and the small end of the Rivulis V2000. Plastic is the usual choice on fertigated water because nylon and composite bodies stand up to fertilizer and chemical exposure.

On a mainline, in the pump shed or ahead of a filter station, look at metal. Bermad's IR-420 and Rivulis's V3000 both run 1" to 16", Netafim's Series 100 iron goes to 12", and Superior's 950PRS covers 3/4" to 3" in red brass. If the mainline is solvent-weld PVC, Netafim's Series 90 is made to glue straight into the run in 3", 4" and 6".

Then decide how much the valve should do. A plain pressure reducing valve only regulates. The solenoid-controlled versions, Bermad's -55 builds, Netafim's PRELTH order code and the Rivulis pressure reducing electric option, regulate and switch the zone on the controller's signal, which removes the separate zone valve upstream. Bermad's IR-920 and IR-820 hydrometers go a step further and meter the water from the same body. One fitting instead of three saves manifold length, unions and leak points on a multi-zone head end.

What do the water, pressure and wiring need to look like?

A hydraulic valve needs inlet pressure comfortably above its setting to regulate at all. Check the operating range first: Bermad's plastics run from 7 or 10 psi up to 150, Netafim's Series 75 from 5 psi, and Superior's 950PRS wants 20 to 200 psi at the inlet to hold 10 to 125 psi at the outlet. When supply falls below the setting the valve simply opens fully, which is by design.

Match the pilot spring to the setting, not the mainline. Bermad's springs run 3–25 psi (green), 7–43 (gray), 12–95 (natural) and 15–150 (blue/white); Netafim's Series 80 uses 7–30 (yellow), 14–65 (green) and 30–90 (red). A setting near the middle of a range regulates more steadily than one at the end. Bermad's Top Pilot valves replace spring swaps with a numbered dial on a 12–40 or 12–80 psi scale.

Flow and water quality matter too. Netafim recommends at least 5 gpm through the Series 90, and any oversized valve at trickle flow tends to hunt. The pilot circuit is small-bore tubing, so filter ahead of the valve or choose a design like the Series 80 with its clog-free labyrinth command-water inlet. On solenoid-controlled valves the controller decides the solenoid: Bermad's IR-220-55 takes the S-390-T-2W for AC or the S-982 for DC latching. Netafim's nylon bodies are rated to 140°F water, its Series 100 iron to 176°F, and Netafim offers a polypropylene Series 75 body with ALD or EPDM diaphragm for aggressive chemistry.

What goes wrong, and how do the four lines differ?

The mistake we see most is a fixed regulator doing a control valve's job. Small inline pressure regulators are fine on a lateral, but at the zone or mainline a hydraulic valve holds its setting across the whole flow range and opens fully when supply drops. The reverse mistake is expecting a reducing valve to protect pressure upstream of itself; that is a pressure sustaining valve, which has its own page.

Other repeat offenders: no gauge downstream, so nobody knows what the valve is actually holding (Superior fits a Schrader valve on the 950PRS so a normal gauge reads the setting); a valve sized to the pipe rather than the flow; a spring range that ends right at the set point; and pilot tubing that has never been flushed.

The four lines take different routes to the same job. Bermad offers the most ways to set and control a valve: spring pilots, the dial-set Top Pilot, solenoid -55 builds and the hydrometer combinations, plus the IR-120 hYflow's composite body with no internal bolts or nuts. Netafim splits by material: Series 75 nylon with one moving part, Series 80 with pilots on the bonnet and no tubes to the body, Series 90 PVC and Series 100 iron. Rivulis runs from the oval-diaphragm V2000 to the piston V2500 for a finer regulation curve and the springless-diaphragm V3000 metal, rated 232 psi above 6". Superior's 950PRS keeps regulating during manual operation, which a separate downstream regulator cannot promise.