Description
Watson McDaniel B-Series — Pressure Regulating Valve for Water, Air, Oil & Other Liquids and Gases
The B-Series Pressure Regulating Valve is designed primarily for reducing pressure in WATER systems. It is also suitable for Air, Oil, and a wide range of other liquids and gases. With larger capacity compared to the O-Series regulator, the B-Series is engineered for reliable performance in industrial and commercial applications.
All B-Series valves now include a Viton diaphragm and disc as standard, providing higher temperature capability and long service life.
Material Specifications
- Body (1/2″ – 2″): Bronze / Stainless Steel
- Body (3″ – 4″): Cast Iron
- Diaphragm & Disc: Viton (300°F max)
- Seat: Bronze / Stainless Steel
Technical Specifications
- Available Sizes: 1/2″ – 4″
- Connections: Threaded NPT, Flanged 125# / 250#
- Maximum Inlet Pressure: 250 PSIG
- Minimum Inlet Pressure: 10 PSIG
- Maximum Differential Pressure: 125 PSIG
- Minimum Differential Pressure: 20% of inlet pressure
Options & Notes
- Must select Spring Code when ordering
- Use the B-Series Spring Selection Table to choose the correct reduced pressure range (replace “X” in model code with spring code)
- Flanged versions use stainless-steel construction for high durability
Flanged Connection – Stainless Steel Adders
- 1/2″ – 1″: 150# FLG add $458.00, 300# FLG add $496.00
- 1½″: 150# FLG add $480.00, 300# FLG add $576.00
B-Series Spring Selection Table
| Reduced Pressure Range (PSIG) | Spring | Code |
|---|---|---|
| 1 – 12 | #4 | 4* |
| 5 – 35 | #3 | 3 |
| 20 – 75 | #2 | 2 |
| 40 – 120 | #1 | 1 |
*Note: Reduced Outlet Pressure 1–12 PSIG (Code 4) available in 1/2″, 3/4″, and 1″ sizes only.
Available Models — Viton Diaphragm & Disc (300°F Max)
| Size / Connection | Model Code* | Body Material | Weight (lbs) |
|---|---|---|---|
| 1/2″ NPT | B-12-N-X-V | Bronze / SS | 8 |
| 3/4″ NPT | B-13-N-X-V | Bronze / SS | 8 |
| 1″ NPT | B-14-N-X-V | Bronze / SS | 9 |
| 1-1/8″ NPT | B-15-N-X-V | Bronze / SS | 13 |
| 1-1/2″ NPT | B-16-N-X-V | Bronze / SS | 15 |
| 2″ NPT | B-17-N-X-V | Bronze / SS | 25 |
| 2″ 150# FLG | B-17-F150-X-V | Bronze / SS | 37 |
| 2″ 300# FLG | B-17-F300-X-V | Bronze / SS | 41 |
| 3″ 125# FLG | B-19-F125-X-V | Cast Iron | 150 |
| 3″ 250# FLG | B-19-F250-X-V | Cast Iron | 160 |
| 4″ 125# FLG | B-20-F125-X-V | Cast Iron | 200 |
| 4″ 250# FLG | B-20-F250-X-V | Cast Iron | 210 |
Example Model Code
B-19-F125-1-V
(B-Series, 3″ 125# Flanged, 40–125 PSIG outlet pressure, Viton Disc & Diaphragm)
Price: $5,069.00
Note: Flange selection may reduce pressure and temperature ratings. Always verify final sizing based on application conditions.

