ITT 150S-HD - User Manual

McDonnell & Miller
Installation & Maintenance
Instructions
MM-219(I)
Replacement Head Mechanism
®
Replacement head mechanisms can be installed without
disturbing existing equalizing connections or disassembly
of components, making repair simple and easy.
Replacement Head Mechanism
Snap Switch
Models:
150S-HD
150S-M-HD
150S-MD-HD
150S-M-MD-HD
158S-HD
158S-M-HD
158S-MD-HD
158S-M-MD-HD
159S-HD
• Before using this product read and understand instructions.
• Save these instructions for future reference.
• All work must be performed by qualified personnel trained in the proper application, instal-
lation, and maintenance of plumbing, steam, and electrical equipment and/or systems in
accordance with all applicable codes and ordinances.
• To prevent serious burns, the boiler must be cooled to 80˚F (27˚C) and the pressure must be
0 psi (0 bar) before servicing.
• To prevent electrical shock, turn off the electrical power before making electrical connections.
• This low water cut-off must be installed in series with all other limit and operating controls
installed on the boiler. After installation, check for proper operation of all of the limit and
operating controls, before leaving the site.
• We recommend that secondary (redundant) Low Water Cut-Off controls be installed on all
steam boilers with heat input greater than 400,000 BTU/hour or operating above 15 psi of
steam pressure. At least two controls should be connected in series with the burner control
circuit to provide safety redundancy protection should the boiler experience a low water
condition. Moreover, at each annual outage, the low water cut-offs should be dismantled,
inspected, cleaned, and checked for proper calibration and performance.
•
• To prevent serious personal injury from steam blow down, connect a drain pipe to the control
opening to avoid exposure to steam discharge.
• To prevent a fire, do not use this low water cut-off to switch currents over 7.4A, 1/3 Hp at
120 VAC or 3.7A, 1/3 Hp at 240 VAC, unless a starter or relay is used in conjunction with it.
Failure to follow this warning could cause property damage, personal injury or death.
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WARNING

Summary

Replacement Head Mechanism

General Safety Warnings

Crucial safety precautions for boiler servicing and operation.

Operation Overview

Electrical Ratings

Details electrical specifications for pump and alarm circuits.

Settings and Differential Pressures

Specifies operational settings and pressure differentials for various models.

Installation Guide

Tools and Preparation Steps

Lists required tools and initial preparation steps for installation.

Installing the Replacement Head

Step-by-step guide for physically installing the new head mechanism.

Electrical Wiring and Safety

Instructions and safety notes for connecting the electrical wiring.

Switch Operation Logic

Wiring Diagrams

Testing and Verification

Maintenance and Blow Down

Blow Down Procedure

Step-by-step instructions for safely blowing down the control.

ITT 150S-HD Specifications

General

Brand	ITT
Model	150S-HD
Category	Switch
Language	English