The Caleffi 536053A 103 is a PresCal HP 536A series heavy-duty piston-type pressure reducing valve with 3/4" NPT female union connections and a 90 to 150 psi setting range, factory set at 115 psi. It is rated to 360 psi maximum upstream pressure at up to 180°F and ships with a 0-200 psi pressure gauge.
Best for the first stage of a two-stage reduction in high-rise and staged-pressure applications, where the ratio between inlet and outlet pressure is too high for a single valve to control. It is not intended as a final-stage valve serving fixtures.
First-stage valve. High range 536x3A models carry a 90 to 150 psi setting range and are designed to take the first stage of pressure reduction ahead of a second valve. Fixtures are normally served by a downstream Pressure Reducing Valve set within code limits. ASSE 1003 applies to the low range 536x4A models only.
Caleffi 2-Year Limited Warranty. Caleffi North America warrants each Caleffi product free from defects in material and workmanship for two years from the date of shipment or delivery. Repair, replacement or refund of the purchase price is at Caleffi's discretion and is the sole remedy. Full terms are set out in the Caleffi North America Limited Warranty. ZOT Supply is a Caleffi distributor.
Key Features
True Piston Operation
The 536A regulates with a guided stainless steel piston and no diaphragm, which holds a stable outlet pressure through severe inlet fluctuation and downstream water hammer.
All-Metal Construction
A DZR low-lead cast brass body with brass spring case and adjusting screw allows outdoor mounting in mild climates, which is what makes the series suited to irrigation duty.
Removable Self-Contained Cartridge
The internal cartridge carries a stainless steel strainer at 0.51 mm (0.2 in) and lifts out for in-line cleaning and servicing without removing the body from the piping.
Dual Union Connections
Union tailpieces on both ports allow complete removal for service or cartridge replacement without disturbing the piping.
Dual Gauge Ports
Gauge ports on both sides of the body suit left-to-right or right-to-left flow, and the valve ships with a 0-200 psi gauge fitted. The spare port carries a brass plug.
High Range: 90 to 150 psi
Set point adjusts across 90 to 150 psi for first-stage duty ahead of a second valve, where a single Pressure Reducing Valve would face too high a reduction ratio.
Technical Specifications
| Product Type | Pressure Reducing Valve |
| Product Series | PresCal HP 536A |
| Valve Type | Piston type, no diaphragm |
| Pressure Range | High range (536x3A) |
| Connection Size | 3/4" |
| Connection Type | NPT female union |
| Union Configuration | Dual union |
| Outlet Pressure Setting Range | 90-150 psi (600-1000 kPa) |
| Factory Setting | 115 psi (800 kPa) |
| Maximum Upstream Pressure | 360 psi |
| Maximum Working Temperature | 180°F (82°C) |
| Maximum Flow | 12.5 gpm |
| Suitable Fluids | Water |
| Pressure Gauge | Supplied, 0-200 psi (0-1400 kPa) |
| Gauge Connections | Dual ports, 1/4" straight female; gauge 1/4" NPT male |
| Strainer Mesh Size | 0.51 mm (0.2 in), stainless steel AISI 304 |
| Body Material | DZR low-lead cast brass CR EN 1982 CC768S |
| Spring Case | Brass EN 12165 CW617N |
| Piston and Control Spindle | Stainless steel AISI 303 |
| Piston Rings | PTFE |
| Seals | Peroxide-cured EPDM |
| Seat | Stainless steel AISI 303 |
| Set Point Adjustment | 10 mm hexagonal allen key |
| Certifications | NSF/ANSI/CAN 61 (180°F/82°C Commercial Hot), file PMG-1356; NSF/ANSI/CAN 372, file PMG-1360. ASSE 1003 applies to the low range 536x4A models only |
| Code Compliance | IPC, IRC, UPC, NPC |
| Shipping Weight | 4.4 lb |
Specifications taken from Caleffi datasheet 01026/23.1 NA, submittal data 03030 NA and brochure 26-45630 (2026). Press-model upstream rating per the brochure note, press models 200 psi (13 bar) maximum.
Documentation
Design Resources
Related Products
- Caleffi 536054A 103 : Low-Range Pressure Reducing Valve 3/4" NPT w/ Gauge
- Caleffi 536053A 109 : High-Range Pressure Reducing Valve 3/4" Sweat w/ Gauge
- Caleffi 536053A 106 : High-Range Pressure Reducing Valve 3/4" Press w/ Gauge
Frequently Asked Questions
What does the Caleffi 536053A 103 do?
The 536053A 103 is a PresCal HP 536A series high range piston-type pressure reducing valve. It takes the first stage of pressure reduction in a two-valve arrangement, dropping a high supply pressure to an intermediate setting between 90 and 150 psi so that a downstream valve can bring the pressure to the level fixtures require.
Why use a piston valve instead of a diaphragm valve?
Caleffi specifies the 536A piston design for duty that punishes a diaphragm, meaning severe inlet pressure swings, downstream water hammer and very high reduction ratios. The all-metal construction also allows outdoor mounting in mild climates, which is why the series is used for irrigation pressure control.
Is the Caleffi 536053A 103 ASSE 1003 certified?
No. ASSE 1003 certification applies to the low range 536x4A models only. This is a high range 536x3A valve intended for first-stage duty rather than as the final valve serving fixtures. It does comply with NSF/ANSI/CAN 61 under file PMG-1356 and NSF/ANSI/CAN 372 under file PMG-1360.
What is the maximum upstream pressure for the 536053A 103?
360 psi (2500 kPa), at temperatures up to 180°F (82°C).
Does the Caleffi 536053A 103 include a pressure gauge?
Yes. Every 536A model ships with a 0-200 psi gauge. Gauge ports are provided on both sides of the body, so the gauge can be fitted to suit left-to-right or right-to-left flow, and the unused port is closed with a brass plug.
How is the set point adjusted?
With a 10 mm hexagonal allen key on the pressure adjusting screw. The factory setting is 115 psi.
- Product Type:
- Pressure Reducing Valve
- Valve Type:
- Piston
- Product Series:
- PresCal HP
- Pressure Range:
- High Range
- Outlet Pressure Range:
- 90-150 psi
- Pressure Gauge:
- Included
- Connection Type:
- NPT
- Connection Size:
- 3/4 inch
- Union Configuration:
- Dual Union
- Max Operating Pressure:
- 360 psi
- Body Material:
- DZR low lead brass
