Ashcroft PD-N7 - Differential Pressure Switches - Manual

Installation and Maintenance Instructions for
ASHCROFT ® P-Series Snap Action
Switches for Differential Pressure Control
INTRODUCTION
The Ashcroft pressure control is a precision device which
features a snap action switch. Fixed deadband is available with
single or dual SPDT Independently adjustable switches with
various electrical ratings. Adjustable deadband is available with
a SPDT switch with various electrical ratings. Several wetted
material constructions for compatibility with pressure media may
be obtained.
The “P” Series Ashcroft snap action pressure switch is available
in both standard NEMA-4 and explosion-proof NEMA 7 & 9 con-
figurations. The enclosure is an epoxy coated aluminum casting.
INSTALLATION
This control is a precision Instrument and should never be left
with internal components exposed. During installation ensure
that covers are in place and conduit openings are sealed.
MOUNTING
Four holes in the bracket supplied are used in surface mounting
of the control. Location of these holes is shown on the general
dimension drawings. An optional pipe mounting bracket is also
available. Mount on a vibration tree surface or pipe. When tight-
ening control to pressure line, always use the wrench flats or
hex on the pressure connection. Never tighten by twisting the case.
PRESSURE CONNECTIONS
For operation as a differential pressure control-connect the high
pressure to the side port marked “H” and the low pressure to the
side port marked “L.”
ELECTRICAL CONNECTION
Remove top cover, cover unscrews (CCW).
On all units except one with terminal blocks – wire directly to
the switch according to circuit requirements. Units with terminal
blocks – wire directly to terminal blocks as required. Terminals
are marked common, norm open and norm closed.
1.06
(27)
2.30
(58)
0.38
(10)
5.00
(127)
Ø 0.31 X 4 HOLES
(8)
3/4 NPT
TYP
Ø 3.90
(99)
4.70
(119)
2.90
(74)
3.06
(78)
(243)
(59)
FEMALE
PORT
H L
(39)
Ø 2.31
3.9
(99)
4.75
(121)
5.50
(140)
1/4 NPT
HIGH
PRESSURE
FEMALE
PORT
1/4 NPT
LOW
PRESSURE
1.55
9.55
STANDARD RANGES
15, 30, 60, 100, 200, 400 psid
© 2007 Ashcroft Inc., 250 East Main Street, Stratford, CT 06614-5145, USA, Tel: 203-378-8281, Fax: 203-385-0499, www.ashcroft.com
All sales subject to standard terms and conditions of sale. I&M009-10011-10/00 (250-2550) AMR 12/07
TERMINAL BLOCK
SWITCH A
TERMINAL BLOCK
SWITCH B
2
1
3
2
1
3
NC
NO
C
NC
NO
C