172-65634MAJ-03 (A-DR20) 6 Oct 2021
6
Correct Usage of the A-DR20 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 A-DR20 should be operated only within its specifications.
2. Installing an ON/OFF Valve (Solenoid Valve or Motorized Valve)
If an on-off valve is required to stop supply of air to the air-using equipment, install
it at the inlet side of the A-DR20.
If a solenoid valve is installed at the outlet of the A-DR20, it will cause heavy
chattering and may lead to damage of the A-DR20. (When the on-off valve opens,
the secondary pressure of the A-DR20 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 air-using equipment and the
pressure reducing valve.
3. Installing a Control and/or Safety Valve
A control valve (i.e. for temperature
control) installed between the
A-DR20 and the air-using equipment
(downstream of the
A-DR20) may raise the pressure
between the A-DR20 and the control
valve when the control valve is
closed, depending on their proximity.
Therefore, this valve should be
installed close to the
air-using equipment, as illustrated.
Also, a safety valve should be
installed downstream of the control
valve.
NOTE: When installing a safety valve to protect the air-using equipment, be sure to
install it on, or directly before the inlet, of the air-using equipment. If the
safety valve is installed between the A-DR20 and a control valve, an
eventual pressure rise could activate the safety valve.
Inlet Side
A-DR20
Motorized Valve
Outlet Side
A-DR20
Solenoid Valve
A-DR20
Safety
Valve
Control
Valve
Air-using
Equipment
A-DR20
Safety
Valve
Control
Valve
Air-using
Equipment