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Actual product may vary from photos.
The McDonnell & Miller 153896 PS-851-M-120 has been discontinued.
Please call us for a suitable alternate product.

(800) 865-5931

Mon-Fri 8am-7pm, Sat 9am-3pm CT

The Series 850 controls provide continuous protection against low water conditions for residential, commercial and industrial applications. Increased probe sensitivity prevents nuisance shutdowns, and a new test feature diagnoses shorted probe problems at installation. The improved userfriendly diagnostic LEDs simplify installation and troubleshooting, ensuring proper operation and saving time.

Standard Features:

  • For residential and commercial applications
  • Manual reset
  • Green LED power and test light
  • Red LED shorted probe and low water indicator light
  • No blow-down required when mounted directly to boiler trappings
  • Meets ANSI specification Z21.13a
  • No lockout with loss of power if probe is in water

Maximum Temp Rating
250 °F
Max Water Pressure
160 PSI
Product Weight
2.7 lbs
120 Volts

In 2002 Alpine Home Air Products became the first company to sell heating, air conditioning and indoor air-quality products online. We have proudly served hundreds of thousands of customers, helping them save time and money by buying their products direct.