Dwyer Instruments Series EDPS Installation and Operating Instructions

Series EDPS Adjustable Differential Pressure Switch

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Specications - Installation and Operating Instructions

Bulletin E-80-EDPS

The Series EDPS Adjustable Differential Pressure Switch is designed for overpressure, vacuum, and differential pressure applications. The scaled adjustment knob allows changes to the switching pressure to be made without a pressure gage. The EDPS is available with settings from 0.08 in w.c. (20 Pa) to 16 in w.c. (4000 Pa). The silicone diaphragm and PA 6.6 body make the Series EDPS perfect for use with air and other noncombustible gases. The Series EDPS can be used in monitoring air

lters, ventilators, and industrial cooling-air circuits along with controlling air and reprotection aps and many other applications.

Adjustable differential pressure switches are for monitoring overpressure, vacuum and

differential pressure of air or other noncombustible, non-aggressive gases. Possible elds of application include:

• Monitoring air lters and ventilators

• Overheating protection for fan heaters

• Controlling air and re-protection dampers

• Monitoring industrial cooling air circuits

• Monitoring ows in ventilation ducts

• Frost protection for heat exchange

Use only with mediums such as air, or other noncombustible or non-aggressive gases.

Otherwise operating faults or accidents may occur.

Mounting

First check the pressure switch to ascertain whether any damage is visible on the housing. If the housing is leaky because of damage, the pressure switch must not be used.

Switching pressure specications apply to vertical installation which is also the

recommended position with pressure connections pointing downwards. If the switches are installed horizontally with AMP connection terminals, the switching values are approximately 0.08 in w.c. (20 Pa) higher.

a) Mounting Position

1. You should mount the pressure switch vertically, with pressure connections pointing downwards. Only then is it possible to drain any condensation moisture, which might occur.

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switching operations.

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SPECIFICATIONS

Service: Air and noncombustible, compatible gases. Materials: Diaphragm material: Silicone; Housing material: Switch body: PA 6.6,

Cover: Polystyrene. Materials UL94 V-0 rated. Temperature Limits: Process and ambient temperature: -4 to 140°F (-20 to 60°C); Storage: -40 to 185°F (-40 to 85°C). Pressure Limits: Max operating pressure: 40 in w.c. (10 kPa) for all pressure

ranges.

Switch Type: Single-pole double-throw (SPDT). Electrical Rating: Max 1.0 A/250 VAC, 50-60 Hz, max switching rate: 6 cycles/min Electrical Connections: Push-on screw terminals. 1/2˝ NPT connection. M20x1.5

with cable strain relief optional.

Process Connections: 5/16˝ (7.94 mm) outside diameter tubing, 1/4˝ (6.0 mm)

inside diameter tubing.

Mounting Orientation: Vertically, with pressure connections pointing downwards. Mechanical Working Life: Over 10 Weight: 4.4 oz (125 g). Enclosure Rating: NEMA 3, IP54. Agency Approvals: CE; ETL approved to UL508 and CSA C22.2#14.

b) Mounting with Screws or Brackets

1. To mount the pressure switch, L-shaped A-288 and S-shaped A-289 mounting

brackets can be ordered separately. To secure the device on the rear side of

the housing, only use the sheet metal screws (3.5 x 8 mm) which are supplied

together with the mounting brackets. Under no circumstances must you use longer screws. Otherwise, the base of the housing could be punctured resulting in the pressure switch leaking.

2. Alternately you can also use the snap-on brackets - to remove it pull upwards.

3. You can also mount the pressure switch directly on a wall. To do this use screws with a maximum diameter of 0.315˝ (8.0 mm), if you use the outer mounting lugs

to screw the device in place. Do not tighten the screws so much that the base of the device is deformed. Otherwise, the pressure switch can be shifted out of position, or leak.

Only if there is no potential for condensate forming can you mount the pressure switch horizontally. In this case, however, the switching values are approximately 0.08 in w.c. (20 Pa) higher as indicated on the scale. In the horizontal position, the pressure switch should be mounted ‘lying down’ only, that is to say with the electrical connections pointing upwards. Do not mount the pressure switch in a hanging position (that is to say, not ‘overhead’ with the electrical connections pointing downwards). Otherwise the device will function inaccurately.

DWYER INSTRUMENTS, INC.

Installing Hoses

Important: Pressure tubing cannot be kinked. Pay particular attention to this point if

you run hoses over an edge. It is better to form a loop. If the hoses are kinked, the device cannot function accurately.

a) For connection to the pressure switch two ttings inherent in the housing are

provided for hoses with an internal diameter of 1/4˝ (6.0 mm).

1. Connect a hose with the higher pressure to socket P1 which is located on the lower section of the housing.

2. Connect a hose with the lower pressure to socket P2 which is located on the middle section of the housing.

After you have installed the hoses, it is absolutely essential to check them for tightness

of t at the connection points, and to make sure that they run without any kinks.

Electrical Connection

Work on electrical installations must only be carried out by electricians who are

specically trained for this purpose.

Setting the Pressure Range

Make absolutely certain that there is no voltage on the electrical connections before you carry out any setting on the pressure switch. Otherwise, it could be fatal if you accidentally touch the electrical connections or the metal adjusting screw while you are performing the settings.

a) Use the setting screw to set the pressure which should trip the switch on increase

of pressure.

1. The indications on the setting screw is only correct for the vertical mounting position.

2. When the pressure falls, the switch returns into its resting position as soon as the pressure falls below the dead band.

Closing the Switch

a) Insert the screw cable connection into the recess provided for this purpose on the

housing.

b) Then place the housing cover in position, and screw it down evenly on to the

pressure switch.

CAUTION: First make sure that there is no voltage on the connecting cable while you

are working on the electrical connections. Otherwise, a possible fatal electric shock may result and the connected equipment may be damaged.

a) The connecting cable can be run to the pressure switch from three sides,

according to choice. The screw cable connection has a plug-in design for this

purpose.

The seal in the screw cable connection is designed for cables with alternative sheath

diameters of 0.275˝ (7 mm) or 0.393˝ (10 mm). Only use these sizes – otherwise the

screw cable connection cannot seal adequately.

1. If using a 0.275˝ (7 mm) connecting cable, you can line up the press nut, the

plain washer and the sealing ring directly on the cable.

2. If using a 0.393˝ (10 mm) connecting cable, you must rst break the inner

rubber ring out of the sealing ring directly on the cable. Then line up the press nut, the plain washer and the sealing ring on the cable.

b) The switching device in this pressure switch is designed as a change-over

contact, as can be seen from the wiring diagram. The rest position is shown in the drawing (pressure below the upper switching point).

1. In the instance where pole 3 (COM) closes to Pole 2, the pressure is increasing (NO);

2. In the instance where pole 3 (COM) closes to Pole 1, the pressure is decreasing (NC).

c) Protect the feed line (to pole 3) by a time-lag fuse, either in control system or

along the line, and do so with:

1. Max.1.0 A/250 VAC, 50-60 Hz, if you are loading the contact with a resistive load;

2. Max 0.4 A/250 VAC, 50-60 Hz, if you are loading the contact with an inductive load (such as relay);

d) The connections are intended for crimp-type sockets, 0.25˝ (6.3 mm).

1. Make sure the crimp connection is perfect, and that the cable lugs t properly

on to the connections.

2. If you do not have any crimp-type sockets available, you can also use the cable lugs which are supplied with mounted screw terminals. However, these

are only intended for rigid copper wire.

3. On ex, it is either necessary to crimp on strand end sleeves – and then you can also screw the strands on – or to crimp cable lugs on directly, as

previously described.

Testing the Setting

Do not operate the system until the housing is closed. Otherwise there is the possibility of a fatal electric shock if you accidentally touch live parts. Check the trip and reset pressures, by slowly increasing the pressure and then allowing it to fall again.

Important: Observe the maximum permissible operating pressure of 40 in w.c. (10 kPa)

which is indicated in the data sheet. Otherwise the pressure switch may be damaged.

MAINTENANCE

Upon nal installation of the Series EDPS Adjustable Differential Pressure Switch,

no routine maintenance is required. A periodic check of system calibration is

recommended. The Series EDPS is not eld serviceable and should be returned if repair is needed (eld repair should not be attempted and may void warranty). Be

sure to include a brief description of the problem plus any relevant application notes. Contact customer service to receive a return goods authorization number before shipping.

DWYER INSTRUMENTS, INC.