11
Adjustment
The PN-DR can set secondary pressure(s) either by operation of the adjustment
handle or adjustment of the motive air pressure, or a combination of both.
To avoid problems such as water hammer and to protect steam and air equipment,
the PN-DR reducing valve should be correctly adjusted.
1. It is necessary to blow down all pipe lines thoroughly.
The blowdown is especially important if the line is new or has been shut down for a
long period of time. Take particular care to ensure that matter such as condensate
and dirt does not remain inside the equipment.
(Stay clear of any pressurized blow-out from the safety valve.)
2. Make sure that the shut-off and bypass valves
located upstream and downstream of the PN-DR
are completely closed.
3. Turn the adjustment handle counterclockwise to
free the coil spring.
Counterclockwise
Fully raise the
adjustment handle
4. Slowly, fully open the shut-off valve at the inlet of the PN-DR.
5. Slightly open the shut-off valve at the outlet of the PN-DR.
6. Slowly turn the adjustment handle clockwise until the desired secondary (steam or
air) pressure is obtained with the pressure of the coil spring. Wait several minutes.
Be careful not to make rapid adjustments as the safety valve may be activated or
equipment may be damaged by water hammer.
Clockwise
Increase Pressure
Counterclockwise
Decrease Pressure
7. Adjust the motive air pressure until the desired secondary (steam or air) pressure
is obtained. Wait several minutes. Be careful not to make rapid adjustments as the
safety valve may be activated or equipment may be damaged by water hammer.
Motive air pressure should be adjusted to set the secondary pressure higher than
the pressure set in step 6. (Using motive air, secondary pressure cannot be set to
a pressure lower than that set in step 6).
8. Slowly, fully open the shut-off valve at the outlet of the PN-DR.
9. When shutting down the system, always close the outlet shut-off valve first and
then the inlet valve.
172-65119MA-01 (PN-DR) 13 Jun 2013
