Mercoid DA/DS-7000 Bourdon Tube Pressure Switches Instruction Manual

: June 9, 2024
: Mercoid

Table of Contents

DA/DS-7000 Bourdon Tube Pressure Switches
INSTALLATION
ACCESSORIES
SPECIFICATIONS
References
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Series DA/DS-7000 Bourdon Tube Pressure Switches
Bulletin IN-523
Instruction Manual

DA/DS-7000 Bourdon Tube Pressure Switches

Specifications – Installation and Operating Instructions

Mercoid DA DS-7000 Bourdon Tube Pressure Switches

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

Mercoid DA DS-7000 Bourdon Tube Pressure Switches -
ACCESSORIES

SPECIFICATIONS

Wetted Materials: Brass, 403 SS, or 316 SS.
Temperature Limit: 180°F (82°C).
Pressure Limit: Maximum pressure of the operating range.
Enclosure Rating: General purpose, weatherproof or explosion-proof.
Repeatability: ±1% of full operating range.
Switch Type: See circuit chart.
Electrical Rating: See electrical ratings chart.
Electrical Connections: Screw terminal.
Conduit Connection: General purpose: 1/2˝ hole for conduit hub; Weatherproof:
1/2˝ conduit hub; Explosion-proof: 3/4˝ female NPT.
Process Connection: General purpose and weatherproof: 1/4˝ male NPT, 1/2˝ male NPT on ranges 15S and 16S; Explosion-proof: 1/2˝ male NPT and 1/4˝ female NPT.
Mounting Orientation: Vertical.
Set Point Adjustment: Thumbscrew.
Weight: General purpose: 4 lb (1.8 kg); Weatherproof: 6 lb (2.7kg); Explosion- proof: 8 lb (3.5 kg).
Deadband: See Ranges and Differentials Chart.
CAUTION
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 lb (2413 mbar) or more.
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 PTFE insert) is turned to the uppermost threaded section of the 1/2˝ 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 leak-proof connection.

Mercoid DA DS-7000 Bourdon Tube Pressure Switches -
purpose

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.

Mercoid DA DS-7000 Bourdon Tube Pressure Switches -
surface

WATERTIGHT AND WEATHERPROOF NEMA 2, 3, 4, 5, TYPES DAW, DRW, DSW
These switches are supplied with flanged case, bottom connection, for surface mounting only.

Mercoid DA DS-7000 Bourdon Tube Pressure Switches -
switches

EXPLOSION-PROOF TYPES DAH, DRH, DSH
Mount with mounting lugs attached to control housing.

Mercoid DA DS-7000 Bourdon Tube Pressure Switches -
controler

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
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.

Mercoid DA DS-7000 Bourdon Tube Pressure Switches -
Switch

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 pressure 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.

Mercoid DA DS-7000 Bourdon Tube Pressure Switches -
Switch2

SINGLE ADJUSTMENT TYPES — FULLY AUTOMATIC:
Models prefixed DS, DSH, DSW, N3DSW are 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.

Mercoid DA DS-7000 Bourdon Tube Pressure Switches -
Switch1

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.
ACETAL BUSHED MOVEMENT ˝B˝
Acetal 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 Acetal movements are identified by the letter ˝B after the suffix number. Examples: -153B, -153UB, etc.
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.

Mercoid DA DS-7000 Bourdon Tube Pressure Switches -
surface1

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.

Ranges| TYPE DA Double Adjustment Minimum Differential (psig)| TYPE DS Single Adjustment Fixed Differential (psig)
---|---|---
Bourdon Tube Material| Range Number| Adjustable Operating Range (psig)| SPDT DA-7031-153 DAW-7033-153 DAH-7031-153| SPDT DS-7231-153 DSW-7233-153 DSH-7231-153| (2) SPDT DS-7231-804 DSW-7233-804 DSH-7231-804
Brass Bourdon Tube| 2
3
1
3A
4
27
5
6
7
8
9| 0 to 30 in Hg VAC
1.0 in Hg VAC-12 1/8 to 15
1/8 to 20
1 to 35
25 in Hg VAC-50
2 to 60
5 to 100
5 to 150
10 to 200
10 to 300| 13.5 in Hg 6
6
6
7
12
9
13.5
24
24
37.5| 3 in Hg
1.5
1.5
1.5
1.5
2.5
2
2.5
3.5
4.75
6| 2.5 in Hg
1.25 in 1.25 1.25 1.5
2
1.5
2
3.5
4
6
403 SS Bourdon Tube| Range Number| Adjustable Operating Range (psig)| SPDT DA-7021-153 DAW-7023-153 DAH-7021-153| SPDT DS-7221-153 DSW-7223-153 DSH-7221-153| (2) SPDT DS-7221-804 DSW-7223-804 DSH-7221-804
25S
26S
5S
6S
8S
9S
9AS
10S
11S
12S
13S
15S
16S| 30 in Hg VAC-60
30 in Hg VAC-75
2 to 60
5 to 100
10 to 200
10 to 300
40 to 350
25 to 600
50 to 1000
100 to 1500
300 to 2500
500 to 5000
800 to 8000| 18
22.5
13.5
19.5
22.5
28.5
30
67.5
142.5
195
390
1350
2250| 3.5
3.5
3
3.5
4.75
7
7
12
22
35
60
200
500| 3

3
2.5
3
4
6
6
10
20
30
50
110
180

DWYER INSTRUMENTS, INC.
P.O. BOX 373
MICHIGAN CITY, INDIANA 46360, U.S.A.
©Copyright 2022 Dwyer Instruments, Inc.
Printed in U.S.A. 3/22
FR# 441853-00 Rev. 4
Phone: 219-879-8000
Fax: 219-872-9057
www.dwyer-inst.com
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