Operation - Pressure Tech MF-414 Series Operating And Service Manual

3. Operation

Turning the hand wheel (or T-Bar) clockwise compresses the load spring, which in turn opens
the main valve, and allows the inlet pressure to pass through the orifice until the outlet
pressure is equivalent to the loading forces set by the compressed spring.
Self venting regulators can reduce the outlet pressure by turning the hand wheel anti-
clockwise, which will allow the excess pressure to vent through the vent port located on the
side of the regulator body. This port should not be plugged or blocked at any time.
Note: Turning the hand wheel anti-clockwise (with pressure on the outlet) should be refrained
on non-venting regulators. Pressure should be reduced in this case by venting downstream of
the regulator, and turning the hand wheel simultaneously anti-clockwise.
The MF-414 series may be offered with pressure limiting, pressure locking or pre-set pressure
options:
Pressure limited regulators are fitted with locknuts on the adjusting mechanism in order to
limit the maximum allowable downstream pressure. Regulators fitted with pressure limiting
locknuts will state the limited pressure on the regulator label and this will also be indicated in
the part number.
Pressure locking regulators are fitted with a locking cap which may be set (when specified) to
pre-determined requirements. It is secured in place by three M5 grub screws which lock
against the bonnet of the regulator creating an anti-tamper device to ensure the pressure
cannot be adjusted accidentally.
Pre-set pressure regulators are adjusted (factory set) to specified customer requirements
within a given pressure range.
Both pressure locking and pre-set pressure regulators will be fully adjustable through a given
pressure range and the maximum allowable working pressures will be indicated on the
regulator label and in the part number.
*Note - A table is available on request defining allowable tolerances for set points within a
given pressure range.
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