© Danfoss | DCS (az) | 2017.11
IC.PI.P10.K8.53 / 520B8307
3
Low pressure limiter
Scale plate directly indicates Low Switching Point. There is no
pointer for Differential.
Differential value is fixed and printed on the scale plate.
1. Set Low Switching Point by adjusting range screw (fig. 7)
2. High Switching Point is equal to Low Switching Point plus
Differential:
HIGH = LOW + DIFFERENTIAL
High pressure limiter
Scale plate directly indicates High Switching Point. There is no
pointer for Differential.
Differential value is fixed and printed on the scale plate.
1. Set High Switching Point by adjusting range screw (fig. 7)
2. Low Switching Point is equal to High Switching Point less
Differential:
LOW = HIGH - DIFFERENTIAL
Protection for settings
The protective cap on adjustment screws may be used to lock
and seal the settings (fig. 6)
Manual reset
For resetting use the screwdriver (Fig. 5)
Manual reset is possible to operate only after return of pressure
to cut-in level.
Before releasing the reset, the cause of the shutdown must be
found and eliminated.
BCP pressure controller with auto reset as a limiting
device
Since the pressure controller
BCP has no lockout with manual
resetting, this function must be realized externally as a part of a
safety logic e.g. by external contactors and/or relays which then
are to be used according to the requirements of prEN50156-1
standard for safety relevant hardware.
External closure must not be interlocked, while loss of auxiliary
energy must lead to a closure.
Resetting must not be automated; it has to be performed
manually.
Resetting on fault must lead to a repeated closure. When BCP
limits, for rising or falling application, the external safety logic
must change to the fail safe position.
Endurance of any external contactors and relays must be
according to EN12952-11, which means 250000 switching cycles
under conditions similar to operating conditions and be capable
of a mechanical life time of 2 000 000 switching cycles.
Conditions similar to operating conditions include chemical and
climatic influences as well as electrical and mechanical stresses.
In addition, contactors must fulfil EN60947 and relays must fulfil
EN60255.
BCP with double bellows
BCP6, BCP6H, BCP7, and BCP7H have a double bellows; an outer
bellows and a regulating (inner) bellows.
When system pressure exceeds the set value, the BCP will
automatically stop the plant. The double bellows system prevents
loss of media in the event of bellows rupture. A rupture in the
inner bellows will cause the switch cut-out pressure to fall about 3
times less the set value, thus the system will stop. A rupture in the
outer bellows will cause the switch cut-out pressure to fall to about
3 bar under the set value, thus providing a fail-safe function.
Safety requirements
Installation
• Internal rules and legislation current in the country concerned
with respect to health and safety at work must be observed
• For safety reasons, the installation of pressure switches must
be carried out only by qualified staff, trained in all technical
aspects of their operation,
• Before installation the pipes must be depressurised and purged
(empty of its fluid) in order to avoid any danger to the operator,
• It is essential to isolate the power supply before wiring
connections are made to avoid possible electrical shock or
damage to equipment. Never touch live parts with your fingers
or with any tool,
• DIN plug supplied by Danfoss and cable approved for the
application must be used. The cable must be connected with
adequate stress relief in order to prevent that pulling forces can
be carried through the cable to the plug.
Commissioning
Before putting pressure switch into operation, check that:
• The working conditions are compatible with the details given
in the product label and this instruction notice,
• All electrical connections have been properly made,
• Installation is tight after assembly.
Operation
• This notice must be available on site where pressure switches
are installed,
• Internal rules and legislation current in the country concerned
with respect to health and safety at work must be observed
• Personnel carrying out any intervention on the pressure switch
must be qualified for the task,
• The pressure switch should be checked regularly to see if it
operates properly,
• The BCP cover must not be removed under any circumstances
• Any overload of the pressure switch must be prevented.
Overloaded or damaged switch must be exchanged.
• It is essential to disconnect the plug before dismounting the
switch from the system,
• All operations must be performed using suitable tools
• It is the responsibility of the user to check that there is no
leakage after a faulty operation or on a periodic basis under
normal conditions,
• Only pressure switches designed, constructed and released
by Danfoss must be used for the applicaiton concerned.
Danfoss can accept no responsibility in case of alterations
made on the pressure switches or the use of them against the
instructions of Danfoss,
• Danfoss is not responsible for any damage which may be
caused by the use of parts, accessories or switches which are
not original Danfoss parts.
