Description
Watson McDaniel 403 Series — Pressure Regulating Valve for High Pressure Steam & Air Applications
The 403 Series is a pilot-operated, piston-actuated pressure regulating valve designed for reducing pressure in STEAM and AIR systems. These valves are built for demanding high-pressure applications and are suitable for installations requiring reliable, stable pressure reduction. The 403 Series features stainless-steel internals for long service life and high performance. They are capable of handling inlet pressures up to 450 PSIG. Both single and double spring options are available for a wide range of reduced pressure settings.
The 403 Series replaces all previously sold 402 Series pressure regulating valves.
Product Overview
- Pilot-operated, piston-actuated design for precise pressure control
- Suitable for High Pressure Steam and Compressed Air systems up to 450 PSIG
- Available with Remote or Internal pressure sensing
- Double spring options for extended reduced-pressure ranges
- Threaded and flanged connection options
- High-strength ductile iron body with stainless-steel internal components
Material Specifications
- Body: Ductile Iron
- Internal Components: Stainless Steel
- Valve Disc & Seat: 420 Stainless Steel
Technical Specifications
- Available Sizes: 1/2″ – 4″
- Connections: Threaded, 150# / 300# Flanged
- Maximum Inlet Pressure: 450 PSIG
- Minimum Inlet Pressure: 20 PSIG
- Maximum Differential Pressure: 250 PSIG
- Minimum Differential Pressure: 15% of Inlet Pressure (10 PSI minimum)
Pressure Sensing Options
- Code R: Remote Pressure Sensing (External sensing line required)
- Code I: Internal Pressure Sensing (No external sensing line required)
- Note: Internal sensing not available with 0–10 PSIG range
403 Series Spring Selection
Select the appropriate spring code (X) based on the required reduced pressure range:
| Pressure Range (PSIG) | Spring | Code | Color |
|---|---|---|---|
| 0 to 10 | #13 | 0013 | Blue & yellow |
| 10 to 20 | #14 | 0014 | Black & yellow |
| 20 to 40 | #7 | 0007 | Red & yellow |
| 40 to 80 | #9 | 0009 | Red & blue |
| 80 to 140 | #5 | 0005 | Green & yellow |
| 0 to 20 (Double Spring) | #13 + #9 | 1409 | Black & yellow |
| 5 to 200 (Double Spring) | #9 + #10 | 0910 | Red & yellow |
Available Models — Remote Pressure Sensing (External Sensing Line Required)
| Size / Connection | Model Code | Weight (lbs) | Weight (lbs) |
|---|---|---|---|
| 1/2″ NPT | 403-12-N-X-R | 20 | 22 |
| 3/4″ NPT | 403-13-N-X-R | 27 | 29 |
| 1″ NPT | 403-14-N-X-R | 32 | 35 |
| 1¼″ NPT | 403-15-N-X-R | 37 | 39 |
| 1½″ NPT | 403-16-N-X-R | 37 | 39 |
| 2″ NPT | 403-17-N-X-R | 56 | 56 |
| 2″ 150# FLG | 403-17-F150-X-R | 60 | 70 |
| 2½″ 300# FLG | 403-18-F300-X-R | 82 | 90 |
| 3″ 150# FLG | 403-19-F150-X-R | 98 | 98 |
| 3″ 300# FLG | 403-19-F300-X-R | 144 | 144 |
| 4″ 300# FLG | 403-20-F300-X-R | 182 | 184 |
Available Models — Internal Pressure Sensing (No External Sensing Line Required)
| Size / Connection | Model Code | Weight (lbs) | Weight (lbs) |
|---|---|---|---|
| 1/2″ NPT | 403-12-N-X-I | 20 | 22 |
| 3/4″ NPT | 403-13-N-X-I | 27 | 28 |
| 1″ NPT | 403-14-N-X-I | 32 | 32 |
| 1¼″ NPT | 403-15-N-X-I | 37 | 39 |
| 1½″ NPT | 403-16-N-X-I | 37 | 39 |
| 2″ NPT | 403-17-N-X-I | 56 | 56 |
| 2″ 150# FLG | 403-17-F150-X-I | 70 | 70 |
| 2½″ 300# FLG | 403-18-F300-X-I | 90 | 96 |
| 3″ 150# FLG | 403-19-F150-X-I | 96 | 98 |
| 3″ 300# FLG | 403-19-F300-X-I | 140 | 140 |
| 4″ 300# FLG | 403-20-F300-X-I | 180 | 184 |
Example Model Code
403-15-N-0014-R
(403 Series, 1¼″ NPT, 10–50 PSIG Spring Range, Remote Sensing)
Note: Flange selection may reduce pressure and temperature ratings. Consult Watson McDaniel documentation for final sizing and configuration.