DH Instruments PPCK PLUS, Operation And Maintenance Manual

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PPCK+™ Operation and Maintenance Manual
Page 13
©2001 DH Instruments, Inc .
2.3.8 VENT PORT
The PPCK+ VENT port is the test exhaust port as well as the vent to atmosphere point used
to set zero gauge pressure. Though a pressure hose can be connected to the VENT port to
direct the vented gas flow, a completely unobstructed connection to atmosphere must be
maintained for PPCK+ reference pressure measurements to operate normally.
The PPCK+ VENT port is 1/8 in. NPT female .
NEVER plug, obstruct or connect a supply pressure to the PPCK+ VENT port.
2.3.9 THE DRAIN PORT
The DRAIN port connects to the low point in the PPCK+ thermal pressure control volume
(see Figures 2, 12). The volume serves as a sump to trap small quantities of liquids that may
return to PPCK+ from the system connected to the TEST port.
The PPCK+ is delivered with a plug installed in the DRAIN port and the port is left plugged
during normal operation. The DRAIN port should occasionally be purged by slowly opening
the fitting with approximately 700 kPa (100 psi) trapped in the PPCK+ (see Section 5.4).
The PPCK+ DRAIN connection is DH200 F .
DH200 F is a gland and collar type fitting for coned and left hand threaded 1/4 in. (6 mm)
OD tube, equivalent to AE SF250C, HIP LF4, etc. DO NOT USE INCORRECT FITTINGS;
DAMAGE TO THE FITTING AND DANGER TO THE OPERATOR COULD RESULT.
2.3.10 THE ATM PORT (BAROMETER)
The ATM pass through is connected to the on-board barometer. The ATM pass through
assures that the on-board barometer is exposed to atmospheric pressure rather than to the
pressure inside the PPCK+ case which may be slightly different from atmospheric pressure.
For calibration or verification of the on-board barometer through the ATM port, a pressure
reference may be connected. The ATM REF port connection is 10-32 UNF F.
Do not plug or obstruct the ATM REF pass through as this may adversely affect GAUGE
mode operation.
NEVER connect a pressure greater than 110 kPa ABSOLUTE (16.5 psia) to the ATM REF port
or damage to the on-board barometer may result.