Dwyer H2 User Manual

Series H2 Dual-Action Explosion-Proof Pressure Switches

Specifications - Installation and Operating Instructions

3-3/8

[85.73]

3/4 NPT ELECTRICAL
CONNECTION

2-15/16

[74.63]

5

[127.00]

Ø2-5/8

[66.68]

1/4 NPT PRESSURE CONNECTION

Bulletin F-64

Accurate, dependable long-lived operation results from the built-in

quality of Duotect®pressure switches. They are designed for sequencing
work where two different actions are to be triggered, as pressure of a
liquid or gas increases or decreases. This permits control and protection
of many types of equipment and systems subject to pressure variations.
The patented design consists of two pistons in a concentric arrangement,
operated by a single diaphragm with one pressure chamber. Each piston
actuates a separate switch independent of the other. The switches may
be adjusted to operate together, or at opposite ends of the range, or at
any two intermediate setpoints. They can be easily field adjusted. For
quick maintenance, the threaded top is removed to adjust or service
switches without disturbing electrical or pressure connections. The
controls are UL and CSA Listed as Explosion Proof, Class I, Groups B,
C, D. Class II groups E, F & G, and weatherproof NEMA-4.

Expanded Listings. Consult factory for models that are UL Listed (not
CSA) Explosion-proof Class I, Groups A, B, C, & D; Class II, Groups E,
F, & G; Weatherproof, NEMA-4X. Contacts rated 10 amp @ 125/250
VAC, 5 amps @ 30 VDC.

SPECIFICATIONS
Wetted Materials: See model chart on next page.
Temperature Limit: 275°F (135°C). CSA approved -20 to 90°C (-4 to

184°F).

Pressure Limit: 1500 psig (103 bar).
Enclosure Rating: UL listed explosion-proof, Class I, Groups B, C, and

D. Class II Groups E, F, and G. Meets NEMA 4X (IP65). CSA optional.
Class I, Groups B, C & D. Class II, Groups E, F, & G -20°C ≤ Tamb ≤
75°C T6 [optional -20°C ≤ Tamb ≤ 40°C T5] Type 4.

Switch Type: One or two SPDT snap switches.
Electrical Rating: 5A @ 125/250 VAC. 5A res., 3A ind. @ 30 VDC.

MV option: 1A @ 125 VAC, 1A res. or .5A ind. @ 30 VDC. Optional
10A switch-consult factory.

Electrical Connections: 18 AWG, 18˝ (460 mm) long.
Conduit Connection: 3/4˝ female NPT.
Process Connection: 1/4˝ female NPT.
Mounting Orientation: Any position.
Set Point Adjustment: Internal nut.
Weight: 2 lb (0.9 kg).
Deadband: Approximately 10% of range.

W.E. ANDERSON DIV., DWYER INSTRUMENTS, INC.

P.O. BOX 358 • MICHIGAN CITY, INDIANA 46361 U.S.A.

Phone: [phone] www.dwyer-inst.com
Fax: [phone] e-mail: [e-mail]

Model Chart - Series H2

2

MV

Example

H2H2S

H2S-2-MV weatherproof and explosion-proof
pressure control; 316SS chamber with FEB
diaphragm and Buna-N O-rings, dual switch,
adjustable range; low: 25-250 psig (1.72-17.2 bar),
high: 30-400 psig (2.07-27.6 bar), gold contact
snap switch for dry circuits.

Construction

Series designator, weatherproof and explosion­proof

Wetted
Material
Options

A

S

Aluminum chamber with Mylar diaphragm and
Buna-N O-rings
316SS chamber with FEB diaphragm and Buna-N
O-rings

Adjustable
Operating
Range

1

1S

Dual switch, adjustable range; low: 3-40 psig
(0.21-2.76 bar), high: 5-75 psig (0.35-5.17 bar)
Single switch, adjustable range 3-75 psig
(0.21-5.17 bar)

2

Dual switch, adjustable range; low: 25-250 psig
(1.72-17.2 bar), high: 30-400 psig (2.07-27.6 bar)

2S

Single switch, adjustable range 25-400 psig
(1.72-27.6 bar)

3

Dual switch, adjustable range; low: 100-1000 psig
(6.89-68.9 bar), high: 150-1500 psig (10.3-103 bar)

3S

Single switch, adjustable range 100-1500 psig
(6.89-103 bar)

CSA

Options

CSA approved construction

MV

Gold contact snap switch for dry circuits

VIT

Fluorocarbon O-rings

EPDM

EPDM O-rings

FEB

FEB diaphragm option where not standard

INSTALLATION

1. Connect pressure switch to supply pressure. (1/4˝ female NPT
connection.)

PRESSURE ADJUSTMENT PROCEDURE

The #1 pressure adjustment (see Figure 1) is for the high range
of the switch. The #2 adjustment is for the low range. Due to
the configuration of the concentric pistons, the #1 setting must
always be the higher of the two.

To adjust the switch, connect it to a source of controlled
pressure such as a hand pump or a regulated fluid supply.

1. Set the high range switch #1 by screwing the elastic stop
nut up or down as required to obtain switch actuation at the
desired pressure. Be sure to set the switch with the pressure
moving in the proper direction: that is, switch actuation on an
increasing pressure or on a decreasing pressure as required
by the application.

2. Set the low range switch #2 in the same manner.

Note: The 4-40 micro switch adjustment screws are factory set
and should not be changed.

WARRANTY

We guarantee our products to be free from defects in
workmanship or material, and will, without charge, at our
option, replace or repair within one year from date of shipment
from our factory any product that may be found defective upon
inspection at our factory. Product to be returned transportation
charges prepaid. This guarantee does not obligate us where
product has been subject to careless handling, improper
application or faulty installation, and we expressly disclaim any
obligation, guaranty or liability whatsoever except as above
stated.

2. Run connecting wires through external conduit and connect. (3/4˝ NPT
connection).

3. Color coding legend is as follows:
Black: Common
Red: Normally Closed with no pressure in the system.
Blue: Normally Open with no pressure in the system.

4. The individual wires are tagged as follows:
CO1 - Common for #1 Pressure Adjustment.

(High Range).

NC1 - Normally Closed for #1 Pressure Adjustment.

(High Range).

NO1 - Normally Open for #1 Pressure Adjustment.

(High Range).

CO2 - Common for #2 Pressure Adjustment.

(Low Range).

NC2 - Normally Closed for #2 Pressure Adjustment.

(Low Range).

NO2 - Normally Open for #2 Pressure Adjustment.

(Low Range).

NO. 2
PRESSURE
ADJUSTMENT

EXPLOSION­PROOF
ALUMINUM
HOUSING

1/4˝ FEMALE
NPT PIPE
CONNECTION
(UNDERSIDE)

Set Point Adjustment

NO. 1
PRESSURE
ADJUSTMENT

EXTRA LONG­LIFE CHROME
VANADIUM
SPRINGS

PRE-WIRED
18 GAUGE
LEADS
18˝ (460 MM)
LONG

Figure 1

©Copyright 2010 Dwyer Instruments, Inc.

Printed in U.S.A. 8/10

W.E. ANDERSON DIV., DWYER INSTRUMENTS, INC.

P.O. BOX 358 • MICHIGAN CITY, INDIANA 46361 U.S.A.

FR# 81-440827-00 Rev. 4

Phone: [phone] www.dwyer-inst.com
Fax: [phone] e-mail: [e-mail]