Dwyer DA-7035N User Manual

Bulletin IN-526-N

Installation Instructions (Preliminary)
Series D-7000-(N) Remote Bulb Temperature Controls

ENCLOSURES – TYPE NO. PREFIX

GENERAL PURPOSE

Prefixed by

DA, DL, DR, DS

CONTROL NUMBERS

Part of the control number following Type No. Prefix identifies the style of the
control case.
The digit 5 of 7035 denotes a plain case with bottom connection.
The digit 8 of 7038 denotes a flanged case with bottom connection.
The digit 9 of 7039 denotes a flanged case with back connection.

CIRCUITS (SWITCH OPERATION)

Suffix number after control number denotes number of circuits and circuit
operation.
Suffix -153 designates SPDT - one circuit closes as other circuit opens.
Suffix - 804 designates 2 ea. SPDT switches - two circuits close as two cir­cuits open.

LOCATION AND MOUNTING OF CONTROL CASE

Follow equipment manufacturer’s instructions or proceed as follows:
Vibration causes erratic operation of any instrument and shortens its life. It is
important to select a location that is reasonably free of vibration. All controls
must be mounted vertical and level. Delrin bushed movements prolong con­trol life by alleviating excessive wear of metal surfaces due to vibration and/or
pulsation. It is identified by the letter “B” after the suffix number. Example: ­2B, -3B, -804B, etc.

General Purpose Types - DA, DS, DL, DR - These controls without a
flange plate are mounted by means of a bracket supplied with the control. For
panel mounted use the holes provided on the flanged case. See drawing
1000F on page 4.

Weather Resistant Types - DAW, DSW, DRW, DLW - For surface mount­ing only. Has flanged case with bottom connection. See drawing 1062 on
page 4.

Explosion-Proof Types - DAE, DSE, DLE, DRE, DLH, DAH, DSH, DRH ­Secure with the mounting lugs provided on the housing. See drawings 98D
and 1350 on page 4.

LOCATION OF REMOTE BULB
To Insure Proper Control Operation:

1. The temperature bulb should be completely immersed in the medium being
controlled.

2. BULB MUST BE CORRECTLY LOCATED AND PROPERLY INSTALLED so
that the temperature changes at the bulb reflect actual temperature changes
of the medium being controlled.

3. Be sure the bulb will not be affected by external temperatures.

4. Bulb may be installed vertically or horizontally. The following precautions
should be taken:
(a) Do not install bulb in dead end of pipe, tank, etc., where it would not be
subject to free circulation of the medium being controlled. See illustration No.

5.
(b) If bulb No. 2 is located in a pipe or duct with diameter larger than the bulb
length, the bulb can be installed perpendicular to the pipe if protected from
possible damage due to flow velocity.
(c) If bulb No. 2 is to be inserted into a pipe with a diameter smaller than the
bulb length (ex. a 2-7/8˝ long bulb in a 1˝ pipe) the bulb should be located lon­gitudinaly in the pipe so that the entire length is exposed to the flowing medi­um (ex. replace an elbow in the pipe with a tee and install bulb as shown in
illustration No. 6 and 7. If pipe is 1˝ diameter or less, provide an enlarged sec­tion around the bulb so that it does not restrict flow.
(d) When bulb No. 2 is to be inserted in a rapidly flowing stream of fluid in a
pipe or duct, make sure that it is mechanicaly protected against the velocity
in order to prevent the bulb from breaking off at the capillary.

5. Gas activated bulbs, unlike vapor pressure bulbs, do not have any eleva­tion effects. Therefore, no compensation is required.

WEATHER-RESISTANT

Prefixed by

DAW, DLW, DRW, DSW

EXPLOSION PROOF

Prefixed by

DAH, DLH, DRH, DSH

BULB PROTECTION

There are three ways to protect bulb No. 2:

1. Before tightening packing gland, pull bulb back into union as far as possi­ble (standard No. 2 bulb with 3/4˝ union only). The union is recessed to pro­vide some support.

2. Where insertion depth is greater than bulb length, use extension sleeve “B”.
See illustration Nos. 8, 9, and 10.

3. Separable Wells (see drawing No. 10): wells slow down heat transfer of
temperature changes to the bulb and consequently increase response time
of control the union will slide back on capillary allowing complete immersion
of bulb in any depth of well.

FOR DIMENSIONS OF BULBS, SEE CHART - PAGE 3

Caution: When installing bulbs with union connections, be careful not to twist
the flexible tubing. Loosen packing nut or union so that the union can turn
freely around tubing. After union is firmly secured to the pipe or tank, position
bulb by sliding tubing through union and then tighten the packing gland nut.

CROSS AMBIENT TEMPERATURE EFFECTS

There are no cross ambient effects associated with these gas actuated units
which are designed with a range number ending with “n”, i.e. -5N.

WHERE TURBULENT OR FAST
FLOWING LIQUIDS PREVAIL

Bulb supports for bulb No. 2 are used where the bulb is mounted in turbulent
or fast flowing liquids or where it is desired to insert the remote bulb at some
distance within a vessel, pipe, or tank. See “B” in illustration Nos. 8, 9 and 10.
The remote bulb should be positioned so that at least one inch of the bulb is
within the extension sleeve “B” (dimension “B”) in order to insure firm support.
No. 2 bulb union is threaded to receive extension sleeve “B”. Extension addi­tion “A” permits extending the mounting through insulation.

ILLUSTRATION NO. 5

INCORRECT

INSTALLATION

Note that a very small
portion of the bulb is
exposed to the direct
path of medium being
controlled. section
containing bulb has
no flow so its temper­ature is affected by
radiation to or from
the surrounding air.

ILLUSTRATION

These two illustrations indicate the bulb is completely
exposed (in direct path) of medium being controlled.

ILLUSTRATION

NO. 8

EXPLOSION PROOF

Prefixed by

DAE, DLE, DRE, DSE

NO. 6

RECOMMENDED

INSTALLATION

ILLUSTRATION

NO. 7

ILLUSTRATION

NO. 9

MERCOID DIVISION

Phone: [phone] www.dwyer-inst.com

DWYER INSTRUMENTS, INC. Fax: [phone] e-mail: [e-mail]
P.O. BOX 258 • MICHIGAN CITY, INDIANA 46361, U.S.A.

Wells (with dimensions “A” and “C” in illus-

WELLS

tration 10) are used to protect the remote
bulb from physical damage or to permit
removal of the bulb without draining the
system.
The use of a well will increase the time lag
of the control since the temperature
change of the controlled medium must be
transmitted through the wall of the well
and then the bulb. Thus when wells are
used, it is important that the well dimen­sion “C” be greater than or equal to the
bulb length “B” to insure that all of the
temperature sensistive portion of the bulb
is within the liquid area.

ILLUSTRATION

NO. 10

WIRING

Wire in accordance with local electrical codes or follow equipment manu­facturer’s recommendations. On general purpose controls, do not attach
ridged conduit to case. use a short strip of BX to relieve conduit expansion
and contraction strains.
Where a control is connected directly into the load circuit, it must be con­nected into the hot side of line.
Do not overload electrically - see nameplate attached to control for electri­cal rating.

ADJUSTMENTS

How to Set Operating Point of Control

DA –

Prefixed by DA, DAE, DAH, DAW –
Provided with double adjustments. Adjust
the upper pointer to set the “high” tem­perature point for switch operation. Adjust
the lower pointer to set the “low” temper­ature operating point. The difference
between the upper and lower pointers is
the operating differential between “on-off”
switch operation. Minimum differential for
each range is shown on Page 3.

DS –

Prefixed by DS, DSE, DSH, DSW –
Equipped with a single adjustment. The
single pointer on the scale sets the tem­perature where switch operation occurs.
Differential is fixed (not adjustable). For
fixed differential of each respective range,
see Page 3.

DR –

DR-7035-153U. A single adjustment sets
the operating point for automatic opera­tion. A push button reset must be operat­ed manually to restore the circuit to the
original position after automatic operation.
Example – Type DR-7035-153L: circuit will
open automatically on a temperature rise
to the temperature indicated by the pointer
on the scale – no matter how much the temperature drops, the circuit will
not reclose until the reset button is operated.
Suffix -L denotes control will operate automatically on an increase.
Suffix -U denotes control will operate automatically on a decrease.

DOUBLE ADJUSTMENT TYPES –
FULLY AUTOMATIC

SINGLE ADJUSTMENT TYPES –
FULLY AUTOMATIC

SEMI-AUTOMATIC CONTROL
WITH MANUAL RESET

TWO-STAGE TEMPERATURE CONTROL

SERIES D-7435

TYPES DA-7435, DAW-7438, DAH-7435, DAE-7435 – This series incor­porates two single pole, double throw snap switches, actuated by the
same Bourdon Tube. The operating point of each switch is adjustable
through an outside knob. The change in temperature which opens and
closes each switch at its respective setting is the “fixed differential” (sensi­tivity) of the switch. The temperature represented by the difference
between the two adjustment points is the temperature “spread” between
operation of the two switches. Upper pointer indicates the operating point
of the “high” temperature circuit. Lower pointer indicates the operating
point of the “low” temperature circuit.

OPERATING RANGES/SERIES D-7435
With Snap-Action Contacts

Range

No.

1N
3N
4N
5N
7N
8N

9N
10N
11N

Scale Range

-60 to 30°F (-50 to 0°C)
0 to 100°F (-18 to 40°C)

50 to 150°F (10 to 65°C)

100 to 200°F (40 to 95°C)

140 to 300°F (60 to 150°C)
250 to 415°F (120 to 215°C)
350 to 550°F (175 to 290°C)

100 to 300°F (40 to 150°C)

100 to 500°F (40 to 260°C)

Max. Temperature

Not To Exceed

150°F (65°C)
240°F (115°C)
250°F (120°C)
300°F (150°C)
500°F (260°C)
550°F (290°C)
600°F (315°C)
500°F (260°C)
600°F (315°C)

Min. Spread

Between Switches

12°F (7°C)
13°F (8°C)
13°F (8°C)

12°F (7°C)
18°F (10°C)
18°F (10°C)
22°F (13°C)
22°F (13°C)
46°F (26°C)

ELECTRICAL RATING
AC capacities: 5A @ 120 V, 5A @ 240 V. (Not available for 440 V).
DC capacity: 5A, 30 V resistive.

Fixed Deadband

Each Switch

4°F (2°C)
4°F (2.5°C)
4°F (2.5°C)
4°F (2.5°C)

6.5°F (4°C)

7°F (4°C)
8°F (4.5°C)
8°F (4.5°C)

16°F (9°C)