Description
Watson McDaniel 3040 Series — Relief & Back Pressure Regulating Valve for Water, Air, Oil & Other Liquids
The 3040 Series Relief & Back Pressure Regulating Valve is designed to maintain desired maximum pressure in vessels or systems by relieving excess pressure into a lower-pressure return line or to atmosphere. It is ideal for applications such as pump bypass control to maintain constant pump discharge pressure and for overpressure protection in various process systems.
Caution: This valve is not intended for use as an emergency or safety relief valve and must not be used on steam.
Material Specifications
- Body (1/2″ – 2″): Stainless Steel
- Diaphragm & Disc: Viton (300°F max)
Technical Specifications
- Available Sizes: 1/2″ – 2″
- Connections: Threaded NPT or Flanged 150#/300#
- Maximum Inlet Pressure: 250 PSIG
Options & Notes
- Must specify Spring Code when ordering to match the required relief/back pressure range.
- Use the 3040 Series Spring Selection Table to determine correct spring code (replace “X” in model code with chosen spring code).
- Special all-stainless-steel construction (1/2″ – 1½″): Add $75 (net). Includes all internals, except diaphragm and disc.
- Other Disc Options Available:
- Teflon (Suffix Code TD): Add $30 (net)
- 316SS (Suffix Code SSD): Add $60 (net)
Flanged Connection — Stainless Steel Adders
- 1/2″ – 1″: 150# FLG add $458.00, 300# FLG add $496.00
- 1-1/2″: 150# FLG add $480.00, 300# FLG add $576.00
3040 Series Spring Selection Table
| Relief Pressure Range (PSIG) | Spring | Code |
|---|---|---|
| 1 – 12 | #4 | 4* |
| 5 – 35 | #3 | 3 |
| 20 – 75 | #2 | 2 |
| 40 – 125 | #1 | 1 |
*Note: Pressure Range 1–12 PSIG (Code 4) available only in 1/2″, 3/4″, and 1″ sizes.
Available Models — Viton Diaphragm & Disc (300°F Max)
| Size / Connection | Model Code* | Body Material | List Price ($) | Weight (lbs) |
|---|---|---|---|---|
| 1/2″ NPT | 3040-12-N-X-V | SS | 763.00 | 8 |
| 3/4″ NPT | 3040-13-N-X-V | SS | 844.00 | 9 |
| 1″ NPT | 3040-14-N-X-V | SS | 864.00 | 9 |
| 1-1/4″ NPT | 3040-15-N-X-V | SS | 1,211.00 | 12 |
| 1-1/2″ NPT | 3040-16-N-X-V | SS | 1,470.00 | 16 |
| 2″ NPT | 3040-17-N-X-V | SS | 3,040.00 | 24 |
| 2″ 150# FLG | 3040-17-F150-X-V | SS | 3,660.00 | 36 |
| 2″ 300# FLG | 3040-17-F300-X-V | SS | 4,213.00 | 40 |
Example Model Code
3040-15-N-3-V
(3040 Series, 1-1/4″ NPT, 5–35 PSIG relief pressure, Viton Disc & Diaphragm)
Price: $1,211.00
Note: Flange selection may reduce pressure and temperature ratings. Ensure proper sizing for your system requirements.