Ashcroft D7 series Manuale di installazione e manutenzione - Pagina 11
Sfoglia online o scarica il pdf Manuale di installazione e manutenzione per Interruttore Ashcroft D7 series. Ashcroft D7 series 19. Pressure, differential pressure and temperature switch
Stampa la paginaNO (Normally Open) Blue
NC (Normally Closed) Red
C (Common) White
Figure 2: Micro switch terminals and wire color codes
SPDT – Wire directly to the switch according to circuit requirements.
2 SPDT – Wire to front switch terminal block (left) and rear switch terminal block (right) as marked. Strip insulation
5⁄16˝, insert in proper terminal connector and tighten clamping screw to secure.
8.4 Starting up and setpoint adjustment
The precondition for start-up is proper installation of all electrical feed lines and metering pipes. All connecting lines
must be laid such that no mechanical forces can act on the device.
Before start-up, the seal on the pressurized connection line must be checked.
Note – As indicated below, adjustment of setpoint is made by use of 7⁄8˝ nut. Precision switch element
mounting screws and bracket adjusting screw are factory sealed and should not be tampered with.
8.4.1 Pressure switch model B7
A single setpoint adjustment nut (7/8") is located centrally at the bottom on the inside of the enclosure.
For accurate setpoint calibration, mount the switch on a calibration stand, a pump or catalog No. 1305 deadweight
gauge tester. A suitable reference standard such as an ASHCROFT Duragauge or Test Gauge is necessary to
observe convenient changes in pressure.
As received, the pressure switch will normally be set to approximately 90% of the indicated range. Pressurize the
system to required setpoint and turn the adjustment nut until switch changes mode. Direction of turning is indicated on
a label affixed to the inside of the control enclosure. When setpoint has been achieved raise and lower pressure to
insure that setpoint is correct.
After installation of the control replace cover to insure electrical safety and to protect internal parts from the
environment.
Note – Since vacuum models are already above setpoint at atmosphere, the Normally Open (NO) circuit will
be closed as received.
.
8.4.2 Differential pressure switch model D7 (high range)
A single setpoint adjustment nut (7⁄8˝) is located centrally at the bottom on the inside of the enclosure.
The direction of turning is indicated on a label affixed to the inside of the control enclosure.
A typical calibration procedure would be as follows:
Static Working Pressure
Adjustable Differential Range
Differential Setpoint
Simultaneously raise the high and low side pressure to 600 psig. Maintain the low side pressure at 600 psig. Raise the
high side pressure to 750 psig to obtain 150 psi differential.
Turn the adjustment nut until the switch changes mode at 150 psi differential. When the setpoint has been achieved,
raise and lower the high side pressure to ensure that the differential setpoint is correct.
- 600 psig
- 5/200 psid
- 150 psi above static working pressure.
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