User Guide

4
The basic principles of operation hold true for all refrigerant solenoid valves,
although certain mechanical variations in construction can be found.
Introduction
Common examples of mechanical variations include:
Short-stroke plungers: The plunger is rigidly connected to the
valve needle or poppet.
Long-stroke/lost-motion plungers: During opening the plunger
imparts a “hammer blow” to the valve stem.
Diaphragm valves: A diaphragm is used instead of a piston.
Common variations
Solenoid valves with a spring-loaded plunger or diaphragm may be installed
in any position; however, older-style solenoid valves that utilize a plunger
dependent on gravity to close must be installed with the plunger in an
upright, vertical position.
Installation position
The most common type of solenoid is the normally closed type. When the
coil is energized, the valve opens. When power is removed, the valve closes.
In a normally open solenoid, the valve closes when power is applied to the
coil and opens when the coil is de-energized.
Normally closed or
open solenoids
Mechanical construction