About Gradual On/Off Valves
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Threaded Gradual On/Off Valves for Boiler Blow-Off
Prevent boiler scale deposits and sediment buildup with these valves that meet ASME standards for boiler drainage applications. They gradually open and close to prevent system damage from suddenly starting or stopping flow.
Wheel handles open and close with multiple turns, providing more controlled, shock-resistant flow than lever handles. They have a nonrising stem that stays in the same position whether the valve is open or closed.
Lever handles open and close faster than wheel handles.
Flow coefficient (Cv) is the amount of water (in gallons per minute) at 60° F that will flow through a fully open valve with a difference of 1 psi between the inlet and the outlet.
For technical drawings and 3-D models, click on a part number.
Wheel Handle and Nonrising Stem—Cast Iron Body and Gate
- Valve Type: Gate
- For Use With: Water
- Packing Material: EPDM Rubber
- Specifications Met: ASME B16.34, ASME B16.5, ASME B31.1, ASME BPVC.I
Lever Handle—Cast Iron Body and Gate
- Valve Type: Gate
- For Use With: Water
- Packing Material: EPDM Rubber
- Specifications Met: ASME B16.34, ASME B16.5, ASME B31.1, ASME BPVC.I
O'all | ||||||||
|---|---|---|---|---|---|---|---|---|
| Pipe Size  | Flow Coefficient (Cv) | Max. Pressure | Temp. Range, °F | End-to-End Lg. | Ht. | Lg. | Each | |
NPT Female | ||||||||
| 1 | 40 | 250 psi @ 350° F | 35° to 350° | 3 5/8" | 14 1/4" | 4 7/16" | 0000000 | 0000000 |
| 1 1/4 | 60 | 250 psi @ 350° F | 35° to 350° | 3 5/8" | 13 1/16" | 4 3/4" | 0000000 | 000000 |
| 1 1/2 | 108 | 250 psi @ 350° F | 35° to 350° | 4 1/2" | 20 3/8" | 5 13/16" | 0000000 | 00000000 |
| 2 | 132 | 250 psi @ 350° F | 35° to 350° | 4 5/8" | 21 5/16" | 6 1/16" | 0000000 | 00000000 |