Delta Controls S24 Installation, Operation & Maintenance Instructions Manual page 2

ALWAYS HOLD A WRENCH ON THE
PRESSURE ENTRY HEX WHEN MAKING
PRESSURE
SWITCH. DO NO TIGHTEN BY TURNING
THE ENCLOSURE.
CHECK THE CONNECTION THREAD SIZE
AND SPECIFICATION ON THE UNIT TO
AVOID MIS-MATCHING
PROCESS CONNECTION ADAPTOR. SEE
DIGIT 11 OF PRODUCT CODE.
Mounting (S71 - Rigid Stem)
Assemble the unit via a thermowell, using the
spanner facility provided and ensuring that:
a) the sensing bulb is fully immersed in the
process temperature
b) the sensing bulb does not bottom out in the
thermowell which could cause damage
Mounting (S71 - Capillary system)
Mount the sensing bulb so that the capillary end is
above the bulb and the bulb is level with, or no more
than 250mm below the base of the instrument. The
stem is fitted with a sliding compression gland to
accommodate different thermowells.
Installation of electrical adaptors and
cable glands to the electrical entry
Either one or two electrical entries can be provided.
The standard entry is a single ISO M20 x 1.5 thread.
Other non-ISO and tapered threads will have their
size and type stamped on the enclosure next to the
entry.
TAKE CARE TO SELECT AND INSTALL
ADAPTORS THAT DO NOT REDUCE THE
ENCLOSURE'S
PROTECTION WHEN IN USE IN ZONE 1
ATEX
HAZARDOUS AREAS.
UNUSED ENTRIES MUST BE FITTED
WITH
FLAMEPROOF STOPPING PLUGS.
ATEX
IT IS A SAFETY REQUIREMENT THAT AT
LEAST 5 FULL THREADS ARE ENGAGED
BETWEEN
GLAND OR STOPPING PLUG, AND THE
ATEX
ELECTRICAL ENTRY WHEN THE UNIT IS
IN OPERATION. NEVER OPERATE THE
UNIT UNLESS THIS CONDITION IS MET.
Alternative electrical entry threads
One or two electrical entries can be supplied with
the following optional thread types:
 ISO to BS 3643 (1981) medium fit 6H up to M25
x 1.5
 DIN 40430 (1971) up to Pg21.
 USAS B2.1 (1968) gauging to clauses 36 & 37 up
to 3/4" NPT.
 BS conduit to BS31 (1940) table 'A' up to 1"
CONNECTION TO
WITH
DEGREE
SUITABLY CERTIFIED
THE ADAPTER, CABLE
www.delta-controls.com
 BSP to BS21(1985) standard threads only as
clause 5.4 gauging to clause 5.2 system 'A' up to
THE
Rp3/4 (medium fit or better).
Wiring
DISCONNECT ALL SUPPLY CIRCUITS
BEFORE WIRING
THE
WIRE IN ACCORDANCE WITH LOCAL
AND NATIONAL CODES. USE CABLES
NO LARGER THAN 2.5 MM 2 (14 AWG)
DO NOT EXCEED ELECTRICAL RATINGS
STATED
NAMEPLATES.
The three switch
"NORMALLY CLOSED",
The following diagram can be used as a
"COMMON".
guide for wiring.
OF
Fig.1A shows the state of electrical contacts at
atmospheric pressure. Note: products with ranges
below atmospheric
reversed between the terminal block and the
microswitch(es) to achieve this state (Fig 1B).
Note: Position of electrical contacts might vary
depending on instrument model, please refer to
product internal marking.
Insert bare wires fully into the terminal block and
tighten securely. Keep wiring tails to a minimum and
check that wires do not interfere with the operating
mechanism. Use the earthing / grounding points
provided.
IOM-INDUSTRIAL REV.C: MAY 2015
IN LITERATURE
terminals are clearly
"NORMALLY
pressure have the
AND ON
marked
OPEN" and
FIG. 1A
FIG. 1B
wiring