Dwyer EDPS - Manual (Page 2)

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 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 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 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 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 2014 Dwyer Instruments, Inc. Printed in U.S.A. 6/14 FR# R8-443802-00 Rev. 3
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.
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˝
w.c. (10 kPa) which is indicated in the data sheet. Otherwise the
pressure switch may be damaged.
Maintenance
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 shipping.
DWYeR inStRUMentS, inc.
phone: 219/879-8000 www.dwyer-inst.com
p.o. BoX 373 • MicHiGan citY, inDiana 46360, U.S.a. fax: 219/872-9057 e-mail: [email protected]