(CAUTION) is used in throughout the manual to identify user warnings and cautions.
(NOTE) is used throughout the manual to identify operating and applications advice and
additional explanations.
High pressure liquids and gases are potentially hazardous. Energy stored in these liquids and gases
can be released unexpectedly and with extreme force. High pressure systems should be assembled and
operated only by personnel who have been instructed in proper safety practices.
Information in this document is subject to change without notice. No part of this document may be reproduced or
transmitted in any form or by any means, electronic or mechanical, for any purpose, without the express written
permission of DH Instruments, a Fluke Company 4765 East Beautiful Lane Phoenix AZ 85044-5318 USA.
DH Instruments makes sincere efforts to ensure accuracy and quality of its’ published materials; however,
no warranty, expressed or implied, is provided. DH Instruments disclaims any responsibility or liability for any direct
or indirect damages resulting from the use of the information in this manual or products described in it. Mention of
any product or brand does not constitute an endorsement by DH Instruments of that product or brand. This manual
was originally composed in English and was subsequently translated into other languages. The fidelity of the
translation cannot be guaranteed. In case of conflict between the English version and other language versions, the
English version predominates.
DH Instruments, DH, DHI, MPC1-1000, and MPC1-3000 are trademarks, registered and otherwise, of
DH Instruments, a Fluke Company.
5.1 GENERAL INFORMATION......................................................................................................................15
5.2 LEA S .....................................................................................................................................................15 K
5.3 TEST PRESSURE WILL NOT CHANGE.................................................................................................19
5.4 PRESSURE CHANGES SLOWLY OR SLUGGISHLY............................................................................21
5.3.1 TEST INLET VALVE ........................................................................................................................................20
5.3.3 TEST OUTLET VALVE ....................................................................................................................................20
The DHI Manually Operated Precision Pressure Controller (MPC1) is designed to provide a compact
and easy to use system for manually setting and adjusting pressures between vacuum and 1 000 or
3 000 psi systems where precise pressure control is required.
MPC1-1000 is for pressures to 1 000 psi (7 MPa), MPC1-3000 is for pressures to 3 000 psi (21 MPa).
The MPC1 is delivered with the inlet valve closed, exhaust valve open and the variable volume (VV)
fully screwed in. Cap plugs are pushed into all rear panel pressure connections.
2.2 SITE REQUIREMENTS
• Gas supply up to maximum amount for model used
• Vacuum source is necessary
2.3 INITIAL SETUP
The MPC1 should be connected to a suitable source of clean, dry, non-corrosive gas using a
1/8 in. NPT male connector to supply (1) on the rear panel. Using the same type connector, hook up
the test system to (2), vacuum source to (4), and any external venting tubing to (3) required to the
corresponding connections on the rear panel. See
The front feet can be folded out to tilt the unit up if desired.
This instrument manually controls pressures from vacuum to 1 000 psi (7 MPa) (MPC1-1000)
or vacuum to 3 000 psi (21 MPa) (MPC1-3000) through the use of valves, a variable volume
(VV) pump and a pressure gauge. Fittings for an outside source of pressure and vacuum are
located on the back panel as are a test connection and vent port. When pressures
(both positive and negative) are needed that are beyond the ability of the VV to generate
by itself, an outside supply of pressure and/or vacuum is required.
The test inlet valve is plumbed directly to the test connection and the high pressure chamber
of the VV. Opening this valve regardless of the position of the equalization valve will result in
an increase of pressure in the test system when pressure is applied to the valve. THIS MAY
RESULT IN AN OVER PRESSURE CONDITION OF THE TEST INSTRUMENT. PLEASE USE
CAUTION WHEN OPERATING THE TEST INLET VALVE.
3.1.2 VALVES
Two types of valves (needle and ball) are used in the MPC1. Two needle valves are used to
control large changes between pressures. A ball valve is used to select between a vacuum
source or an atmospheric reference (vent).