Chapter hvac engineering Fundamentals: Part 1 Introduction

Design Procedures: Part 6
259
Figure 8.42
Pneumatic time-delay relay.
Figure 8.43
EP relay arrange-
ment.
shown in Fig. 8.43. The
pneumatic-electric
(PE)
relay
is a pressure
switch which trips at some desired control air pressure. The set point
is usually adjustable. This is used most often to provide control of an
electric circuit in response to a pneumatic sensor or controller. A
re-
versing relay
provides a modulating output which is the reverse of the
Design Procedures: Part 6
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