Green Guru LLC Irrigation & Landscape Lighting

Pressure Discipline

Caleffi 535361HA PRV (with gauge)

When excessive source pressure is shortening system life, a correctly sized pressure reducing valve (PRV) is one of the highest-ROI reliability upgrades. The Caleffi 535361HA adds an on-body gauge to support quicker verification and cleaner follow-up service.

Built-in gauge 1" NPTF connections Low-lead brass Scoped under flow

Why we like a gauge on the PRV

  • Faster verification: quick checks during seasonal service and troubleshooting.
  • Better tuning: supports pressure discipline targets (often ~65 PSI with a regulated ceiling of 75 PSI, tuned for real-world performance).
  • Cleaner follow-through: makes it easier to confirm “under-flow truth” after changes to nozzles, heads, or zone demand.

When we recommend this model

  • Static source pressure is consistently elevated (often 85+ PSI locally)
  • Systems with repeat head failures, misting, or leak symptoms tied to pressure stress
  • Install paths where a gauge adds serviceability and better documentation over time
Scope note: we choose PRV hardware based on service size, peak zone demand, and pressure under flow (zones running). We confirm fit on-site before selecting a specific model.
Union alternative: For sweat union installs, the common 1" gauge option is 535961HA. For 2" services, the common gauge option is 535991HA.

Scaling up (bigger services)

If service size and demand exceed a 1-inch class install, Caleffi offers larger NPTF options (including 1-1/4") with higher flow ceilings and broader pressure ranges. We’ll recommend the right size during scoping so performance stays stable and maintainable.

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Fit & availability

We confirm fit and compatibility during service and can supply or install owner-supplied hardware.

At a glance

Caleffi 535361HA facts
IndustryIrrigation
BrandCaleffi
Part number535361HA
TypePressure reducing valve (PRV) with gauge
MaterialBrass (low-lead)
Connection1" NPTF (with gauge)
Best fitPressure discipline installs where gauge visibility improves service follow-through

Pressure issue suspected?

We can test pressure at the source and under flow, then scope the correct mix of PRV, pressure-regulating heads, and programming changes.

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Related: Irrigation upgrades.