Dwyer Series EDPS User manual

Dwyer Series EDPS User manual
Bulletin E-80-EDPS
Series EDPS Adjustable Differential Pressure Switch
Specifications - Installation and Operating Instructions
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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
filters, ventilators, and industrial cooling-air circuits along with controlling air and fireprotection flaps 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
fields of application include:
• Monitoring air filters and ventilators
• Overheating protection for fan heaters
• Controlling air and fire-protection dampers
• Monitoring industrial cooling air circuits
• Monitoring flows 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.
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
Switching pressure specifications 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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[P2] -
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+ [P1]
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 ambient temperature from -4 to 140°F (-20 to 60°C).
Pressure Limits: Max. Operating Pressure: 40 in w.c. (10 kPa) for all pressure
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 106 switching operations.
Weight: 5.6 oz (160 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.
Phone: 219/879-8000
Fax: 219/872-9057
e-mail: [email protected]
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 fittings 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 fit 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
specifically trained for this purpose.
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
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 first 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
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 fit 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 flex, 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.
©Copyright 2018 Dwyer Instruments, Inc.
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
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
b) Then place the housing cover in position, and screw it down evenly on to the
pressure switch.
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.
Upon final 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 field serviceable and should be returned if
repair is needed (field 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
Printed in U.S.A. 12/18
FR# 443802-00 Rev. 6
Phone: 219/879-8000
Fax: 219/872-9057
e-mail: [email protected]
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