5
Correct Usage of the PN-DR Direct-acting Pressure
Reducing Valve
Install properly and DO NOT use this product outside the recommended
operating pressure, temperature and other specification ranges.
Improper use may result in such hazards as damage to the product or
malfunctions which may lead to serious accidents. Local regulations
may restrict the use of this product to below the conditions quoted.
CAUTION
1. The PN-DR should be operated only within its specifications.
2. Installing an ON / OFF Valve (Solenoid Valve or Motorized Valve)
Motorized
Valve
Inlet Side
Pressure
Reducing
Valve
Outlet Side
Solenoid
Valve
Pressure
Reducing
Valve
If an on-off valve is required to stop supply of steam or air to the equipment, install
it at the inlet side of the PN-DR.
If a solenoid valve is installed at the outlet of the PN-DR, it will cause heavy
chattering and may lead to damage of the PN-DR. (When the on-off valve opens,
the secondary pressure of the reducing valve changes from zero to the set
pressure. Passing through an area of the reducing ratio of less than 30:1 where
adjustment is impossible, chattering occurs momentarily.) To save energy, install
the on-off valve as near to the boiler, or compressor, as possible.
NOTE: To prevent water hammer, it is recommended that a slow-acting motorized
on-off valve be used. If a fast-acting solenoid valve is used, the potential water
hammer effect can damage the equipment and the pressure reducing valve.
3. Installing a Control and/or Safety Valve
Safety
Valve
Steam or Air-using
Equipment
Control
Valve
Pressure
Reducing
Valve
Safety
Valve
Steam or Air-using
Equipment
Control
Valve
Pressure
Reducing
Valve
Safety
Valve
Control
Valve
Steam or Air-using
Equipment
Pressure
Reducing
Valve
Safety
Valve
Control
Valve
Steam or Air-using
Equipment
Pressure
Reducing
Valve
A control valve (i.e. for temperature control) installed between the PN-DR and the
equipment (downstream of the reducing valve) may raise the pressure between
the PN-DR and the control valve when the control valve is closed, depending on
the spatial relationship. Therefore, this valve should be installed close to the
equipment, as illustrated. Also, a safety valve should be installed downstream of
the control valve.
NOTE: When installing a safety valve to protect steam or air equipment, be sure
to install it on, or directly before the inlet, of the equipment. If the safety valve is
installed between the PN-DR and a control valve, an eventual pressure rise could
activate the safety valve.
172-65119MA-01 (PN-DR) 13 Jun 2013
