Mercoid DS-7000, DA-7000 Installation Manual

Bulletin IN-523

Contact: Northeast Controls Incorporated

P.O. Box 275 - Upper Saddle River, New Jersey 07458

Tel: [phone] | Fax: [phone] | [e-mail]

www.nciweb.net/dwyer

Series DA/DS-7000 Bourdon Tube Pressure Switches

Specifications - Installation and Operating Instructions

2-1/4

[57.15]

6-1/64

[152.8]

DIA.

MERCOID
CONTROL

1/4 N.P.T.

ADJUSTMENT SCREWS

7/8 [22.23]

CONDUIT HOLE

5/8 [15.88]

1-5/8

[41.28]

1/2 [12.7]

Series DA/DS-7000 Bourdon Tube Pressure Switches

are SPDT snap-action switches that combine extremely
high sensitivity and repeatability with easily adjustable set
and reset points through non-interactive external adjust­ments. These switches have visible calibrated dials for set
points and on-off indicators to indicate switch actuation.
DA models are equipped with two external adjustments.
One sets the high pressure operating point; the other sets
the reset point. Deadband or the difference between set
and reset points is adjustable over the full scale. DS mod­els have a fixed deadband.

NOTE: The DS7300 has no status indicator.
INSTALLATION

The switch may be mounted in any position. Select a loca­tion recommended by equipment manufacturer. Where
excessive vibration occurs, mount the switch remotely,
using an appropriate remote connection and mounting
bracket. See accessories, below.

ACCESSORIES

Mounting

Bracket

Remote

Connection

PHYSICAL DATA
Pressure Range: Models range from 0 to 30” Hg (0 to

762.5 mm/Hg) Vac. to 800 to 8000 psig (55.16 to 551.6
bar).

Maximum Temperature: 180°F (82°C). For higher tem­perature media applications, a remote connection or siphon
(pigtail) should be used.
Pressure Connections:1/4″ NPT standard;1/2″ NPT on
ranges 500 to 5000 psig and 800 to 8000 psig.

Housing: Pressed steel with transparent cover.
Wiring Connections: Three-screw type.
Wetted Parts: Same as Bourdon tube material (brass,

403SS or 316SS) on all ranges except 23K, 24K, and 9K,
which have carbon steel bottom connections.
Weight: 4 lb/1.8 kg (standard); 6 lb/2.7 kg (weatherproof);
8 lb/3.6 kg (explosion-proof)

Max. Pressure: Max. adjustment of operating range.

CAUTIONS:

Control movement must not be oiled. Do not overload.
Note electrical rating on name plate and be sure that total
current passing through the switch is within specified rat­ing.

When testing a boiler or system, never exceed maximum
pressure rating on control or it may be seriously damaged.
Remove control if higher pressures are required.

Do not fail to use a siphon on steam where range is 35 lbs
(2413 mbar) or more.

Pigtail

Siphon

Bulletin IN-523

Page 2

GENERAL PURPOSE CONTROLS, TYPES DA, DL, DR, DS

Mount control in any position. Do not twist the case when
installing. Use a wrench on the square part of the control
connection. On controls with operating Range No. 15S (500
to 5000 psi (34.47 to 344.75 bar)) or Range No. 16S (800
to 8000 psi (55.16 to 551.6 bar)), be sure the special seal­ing nut (with Teflon®insert) is turned to the uppermost
threaded section of the1/2″ pressure connection. Apply a
flat open-end wrench to the flat side of the bottom pressure
connection when piping the control. After properly con­necting the control, tighten the sealing nut to assure a leak­proof connection.

HOLES FOR

FLANGE SCREWS

DA21
DA31
DA41

3

1/2 CONDUIT
CONNECTION

6-1/64 DIA.

DA22

1-1/2

1/4 NPT

NPT

1/4

[«\«1

DA32
DA42

1-1/8

General Purpose

Types DA, DS, DR, DL

WEATHER-RESISTANT (RAINTIGHT)
NEMA 2, 3, TYPES N3DAW, N3DRW, N3DSW

These switches are supplied with flanged case, bottom con­nection, for surface mounting.

WATERTIGHT AND WEATHERPROOF
NEMA 2, 3, 4, 5, TYPES DAW, DRW, DSW, C4DAW*,
C4DAW*, C5DSW*

These switches are supplied with flanged case, bottom con­nection, for surface mounting only.

*

Conforms to Canadian Standards Association requirements

REAR FLANGE MOUNTING HOLES (3)

7 DIA.

ADJUSTMENTS

GASKETED COVER

1/4 NPT

[\««1

2-13/16

1/2

CONDUIT

HUB

Weather-Proof

Types DAW, DSW, DRW

EXPLOSION-PROOF TYPES DAH, DRH, DSH

Mount with mounting lugs attached to control housing.

3-1/2

BREATHER

(OPTIONAL)

MOUNTING

HOLES (OPTIONAL)

13/32 DIA.

5

3/4 CONDUIT
CONNECTION

FLANGED CASE CONTROLS

Mount by means of the three holes in the flange. Note:
Series D7030 when used for steam with operating ranges of
35 psi (2.413 bar) or higher, must be siphoned to prevent
live steam entering the Bourdon tube. With high-pressure
steam exceeding 100 psi (6.895 bar), use a remote con­nection. (Note accessories on Page 1.)
Series D-7020 incorporate an orifice as standard in the
pressure connection to dampen surges or pulsations.

DA24
DA34
DA44

13/64

DIA.

6-1/2 DIA.

BACK

CONNECTION

DA23
DA33
DA43

BOTTOM CONNECTION

Flange for Surface Mounting

9-7/8

7-3/4

1/2 NPT

1/4 NPT

Explosion-Proof

Types DAH, DRH, DSH

WIRING

Wire in accordance with the National Electrical Code and
local regulations. For general purpose controls, use a short
piece of BX between the rigid conduit and the control so the
control will not be subjected to conduit expansion and con­traction. Where the control is directly connected into the
load circuit, it should be connected into the hot side of the
line. Do not exceed electrical rating as stamped on the con­trol nameplate. DS-7300 controls are equipped with a ter­minal block. Field connection should be made to terminal
block pole in common with required pole of the control’s
switch. The color code is:
Black - Common
Blue - ON Hi
Red - ON Lo

Bulletin IN-523

PIVOT POINT
BEARINGS,
TOP & BOTTOM,
BUSHED WITH DELRIN

SWITCH CARRIER
STOP POST SLEEVED
WITH DELRIN

DELRIN PIN

DELRIN PIN

BAR LINK

DELRIN BRUSHED

PIVOTAL END

BEARING &

CONNECTION

BAR PIN OF

DELRIN

Page 3

ADJUSTMENTS: HOW TO SET OPERATING POINT
Double Adjustment Types - Fully Automatic:

With double-adjustment switches (prefixed DA, DAH or
DAW), adjust the upper pointer “U” to set HIGH PRESSURE
POINT for switch operation and adjust the lower pointer “L”
to set LOW PRESSURE OPERATING POINT. The differ­ence between the “U” and “L” pointers is the operating dif­ferential between “on-off” switch operation.

Switch Indicator

Orange indicates

on high

U - Upper

Pointer

L - Lower

Pointer

Double-Adjustment Types

Fully Automatic

Semi-Automatic Control with Manual Reset:

Models prefixed DR, DRH, DRW and with suffix L or U
(example: DR-7021-153U) have a single adjustment that
sets the operating point for automatic operation. A push­button reset must be operated manually to restore the cir­cuit to the original position after automatic operation.
Example: Type DR-7021-153L has a circuit that opens
automatically on a pressure rise to the pressur e indicated by
the pointer on the scale; no matter how much the pressure
drops, the circuit will not re-close until the reset button is
operated. Suffix L denotes control will operate automati­cally on an increase. Suffix U denotes control will operate
automatically on an decrease.

Adjustment

SINGLE ADJUSTMENT TYPES—FULLY AUTOMATIC:

Models prefixed DS, DSH, DSW , N3DSW ar e equipped with
a single adjustment. Differential is fixed (not adjustable). The
single pointer on the scale sets the pressure at which switch
operation occurs. Differential is listed in chart indicates
approximate fixed differential.

Switch

Operating

Indicator

Single

Adjustment

Single Adjustment Types Fully Automatic

LOCKING DEVICE

When the control has been adjusted to desired range, the
locking bar may be inserted between the adjustment
screws with the slot passing over the projecting lugs. By
placing a sealing wire between the locking bar and the hole
in the lug protruding from the adjustment assembly, adjust­ments cannot be tampered with.

For DRF, DAW, DRW, adjusting knob cover may be sealed
in place with sealing wire through cover bolt hole. For DAH,
sealing wire may pass through locking bar and hole in hub
above adjusting knobs.

DELRIN®BUSHED MOVEMENT “B”

Delrin®bushed movements prolong control life by alleviating
wear of metal surfaces due to excessive vibration and/or
pulsation. They also prolong switch life in environments
where corrosion may be a factor. Models with Delrin move­ments are identified by the letter “B after the suffix number.
Examples: -153B, -153UB, etc.

*Delrin is a registered trademark of E. I. DuPont de Nemours & Co.

CONTROL NUMBER

Part of the control number (the fourth number in the sequence)
identifies the type of control case. Digit 1 of 7021, 7031, 7041,
denotes a plain case with bottom connection. Digit 2 of 7022,
7032, etc., denotes a plain case with back connection. Digit 3 of
7023, 7033, 7043, etc., denotes a flanged case with bottom con­nection. Digit 4 of 7024, 7034, etc., denotes a flanged case with
back connection. (Digit 3 of 7321, 7331, 7341, etc., denotes her­metically sealed snap switch.)

Semi-Automatic Types

with Manual Reset

Reset

Delrin®Bushed Movement “B”

CIRCUITS (SWITCH OPERATION)

Suffix number after control number denotes switch action:
Suffix -153 designates SPDT; one circuit closes as other circuit
opens.

Suffix - 804 designates two SPDT switches; two close,
two open.

Bulletin IN-523

Contact: Northeast Controls Incorporated

P.O. Box 275 - Upper Saddle River, New Jersey 07458

Tel: [phone] | Fax: [phone] | [e-mail]

www.nciweb.net/dwyer

Page 4

Bourdon Tube

Material

Brass

Bourdon Tube

403SS

Bourdon Tube

316SS

Bourdon Tube

316SS

Bourdon Tube

Carbon Steel

Bottom

Connection

Code

D
E
F
G
K

RANGES:

Range

Number

2
3
1

3A

4

27

5
6
7
8
9

Range

Number

25S
26S

5S
6S
8S

9S
9AS
10S
11S
12S
13S
15S
16S

Range

Number

26E

23E

6E

24E

9E
21E
22E
11E
13E

Range

Number

23K
24K

9K

Two SPDT Switches*

AC Capacity

120V 240V 480V

15A 15A NA

15A 15A 15A

12A 10A 5A

Adjustable

Operating Range

(PSIG)

0-30” Hg Vac

1.0” Hg Vac-12 psig
1/8-15 psig
1/8-20 psig

1-35 psig

25” Hg Vac-50 psig

2-60 psig
5-100 psig
5-150 psig

10-200 psig
10-300 psig

Adjustable

Operating Range

(PSIG)

30” Hg Vac-50 psig
30” Hg Vac-75 psig

2-60 psig

5-100 psig
10-200 psig
10-300 psig
40-350 psig
25-600 psig

50-1000 psig
100-1500 psig
300-2500 psig
500-5000 psig
800-8000 psig

Adjustable

Operating Range

30” Hg Vac- 75 psig

5-75 psig
10-100 psig
10-150 psig
10-300 psig
30-400 psig
75-800 psig

100-100 psig

200-2500 psig

Adjustable

Operating Range

10-150 psig

10-300 psig

Electrical Ratings

TYPE DA

Double Adjustment

Minimum Differential

SPDT

DA-7031-153
DAW-7033-153
DAH-7031-153

9” Hg
4 psig
4 psig
4 psig
5 psig
8 psig
6 psig

9 psig
16 psig
16 psig
16 psig

SPDT

DA-7021-153
DAW-7023-153
DAH-7021-153

12 psig
12 psig

9 psig
13 psig
15 psig
20 psig
19 psig
45 psig
95 psig

130 psig
260 psig
900 psig

1500 psig

SPDT

DA-7041-153

(PSIG)

(PSIG)

5-75 psig

5A @ 250 AC. Resistive & Inductive; 30V DC Resistive

5A @ 125/250 AC, Resistive; 30V DC Resistive

DAW-7043-153

DAH-7041-153

10 psig

8 psig
10 psig
11 psig
28 psig
52 psig

120 psig
190 psig
400 psig

SPDT

DA-7041-153

DAW-7043-153

DAH-7041-153

8 psig
11 psig
28 psig

See Code F
See Code D

ELECTRICAL RATINGS

DC Capacity

120V 240V

.5A .25A

NA NA

.5A .25A

SPDT

DS-7231-153

DSW-7233-153

DSH-7231-153

3” Hg

1.5 psig

1.5 psig

1.5 psig

1.5 psig

2.5 psig
2 psig

2.5 psig

3.5 psig

4.75 psig
6 psig

SPDT

DS-7221-153

DSW-7223-153

DSH-7221-153

3.5 psig

3.5 psig
3 psig

3.5 psig

4.75 psig
7 psig

7psig
12 psig
22 psig
35 psig
60 psig

200 psig
500 psig

SPDT

DS-7241-153
DSW-7243-153
DSH-7241-153

3.5 psig
4 psig

3.5 psig

4.5 psig
8 psig

12 psig
25 psig
35 psig
75 psig

SPDT

DS-7241-153

DSW-7243-153

DSH-7241-153

4 psig
4 psig
8 psig

See Code E

TYPE DS

Single Adjustment

Fixed Differential

(2) SPDT

DS-7231-804
DSW-7233-804
DSH-7231-804

2.5” Hg

1.25” psi

1.25 psig

1.25 psig

1.5 psig
2 psig

1.5 psig
2 psig

3.5 psig
4 psig
6 psig

(2) SPDT

DS-7221-804
DSW-7223-804
DSH-7221-804

3 psig
3 psig

2.5 psig
3 psig
4 psig
6 psig
6 psig

10 psig
20 psig
30 psig

50 psig
110 psig
180 psig

(2) SPDT

DS-7241-804

DSW-7243-804

DSH-7241-804

4 psig

2.5 psig

4 psig
3 psig

6 psig
10 psig
17 psig
30 psig
95 psig

(2) SPDT

DS-7241-804

DSW-7243-804

DSH-7241-804

2.5 psig
3 psig
6 psig

See Code D See Code K

AC Horsepower

120V 240V

1/8 1/4
1/4 1/2
1/4 1/2

DSW-7333-153

DSH-7331-153

DSW-7323-153
DSH-7321-153

SPDT

DS-7331-153

5” Hg
3” psi
3 psig
3 psig
3 psig

3.75 psig
3 psig

3.75 psig

5.25 psig

6.75 psig
9 psig

SPDT

DS-7321-153

5.25 psig

5.25 psig

4.5 psig

5.25 psig

7.125 psig

10.5 psig

10.5 psig
18 psig
33 psig

52.5 psig
90 psig

300 psig
750 psig

SPDT

DS-7341-153

DSW-7343-153

DSH-7341-153

5.25 psig
6 psig

5.25 psig

6.75 psig

12 psig
18 psig

37.5 psig

52.5 psig

112.5 psig

SPDT

DS-7341-153

DSW-7343-153

DSH-7341-153

6 psig
6 psig

12 psig

Circuit
Suffix No.

-153

-804
*Note: Minimum differentials increase when using multiple circuits. Controls using #804 circuits in ranges over

35 psig have 30% higher minimum differentials; ranges under 35 psig are not available in Code F.

Switch Action on Pressure/Temperature Increase

SPDT:one OPENS as one CLOSES

(2) SPDT: two OPEN as two CLOSE

Electrical Rating Code

D-7000 D-2000 D-7300

D E K
F* G

©Copyright 2001 Dwyer Instruments, Inc. Printed in U.S.A. 4/01 FR# 76-441853-00 Rev.1