McDonnell & Miller 171702 150S High Pressure Low Water Cut-Off & Boiler Pump Controller (1 Inch NPT, 150 PSI)
McDonnell & Miller 171702 150S High Pressure Low Water Cut-Off & Boiler Pump Controller (1 Inch NPT, 150 PSI)
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| Performance Parameter | Engineering Baseline Value |
|---|---|
| Manufacturer Part Number (MPN) | 171702 |
| Model Designation | 150S (Standard Differential Series) |
| Equalizing Pipe Connections | 1" NPT (Female Threaded) |
| Maximum Operating Steam Pressure | 150 PSI (10.5 kg/cm²) |
| Switch Configuration | 1 SPST (Pump Control) / 1 SPDT (LWCO & Alarm) |
| Electrical Rating (Pump Circuit) | 7.4A @ 120VAC / 3.7A @ 240VAC (345 VA Pilot Duty) |
| Enclosure Protection Rating | NEMA 1 General Purpose Heavy Metal Housing |
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Apply for Trade Account & Terms →McDonnell & Miller 171702 (Model 150S) Combination Low Water Cut-Off & Pump Controller
Designed for primary or secondary low water fuel cut-off and automatic feed pump regulation on commercial and industrial steam boilers, the McDonnell & Miller 171702 (Model 150S) is the industry-standard mechanical level controller for high-pressure steam applications. Operating at maximum steam pressures up to 150 PSI (10.5 kg/cm²), this heavy-duty control features a rugged cast iron float chamber and corrosion-resistant Monel bellows seal isolation.
Unlike maximum-differential variants, the standard 150S features factory-calibrated standard switching levels to provide tight, responsive water line control. Its internal mechanism incorporates two heavy-duty snap action switches—a single pole, single throw (SPST) switch for direct boiler feed pump activation and a single pole, double throw (SPDT) switch for low water burner cut-off and alarm circuit operation.
Key Performance & Engineering Highlights:
- Standard Switching Differential: Provides tight water line maintenance and rapid low-water burner shutdown protection.
- Sealed Monel Bellows Isolation: Prevents steam, condensate, and boiler water contaminants from entering the switch housing, extending mechanical life.
- Dual Snap Switches: Contains 1 SPST snap switch for feed pump control and 1 SPDT snap switch for low water fuel cut-off (LWCO) and alarm activation.
- 1" NPT Female Tappings: Standard 1" female NPT side equalizing connections simplify rigid pipe mounting directly to the boiler shell or external water column.
⚠️ Application Profile: Essential for commercial and industrial steam boilers of any steaming capacity requiring primary/secondary low water fuel cut-off, automated boiler feed pump control, or high/low level alarm signaling up to 150 PSI.
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