PRM
Pressure switch with
manual setting for heating
systems.
0402101 1/4”F
3
Part No. Size bar
Pressure switch Series PRM is a switch with normally
closed contact; when the pressure of the system exceeds
the set pressure, the contacts are opened, thus interrup-
ting the circuit. Closing of the contacts (resetting of the
pressure switch) should be performed manually by pres-
sing the reset button.
APPLICATION AND OPERATION
To adjust the cut-off pressure, turn adjusting nut (2). The
set value can be read on relative scale (1). To reactivate
the system after making the adjustment, wait for the
pressure to drop at least 0.4 bar below set pressure, then
press the reset button at the bottom of the pressure
switch.
ADJUSTMENT OF SET PRESSURE
Contact (b) - (c) is normally closed (it opens when the set
pressure is reached). Connection to earth is via terminal
(a). View of the terminal board from above after removing
the cover:
ELECTRICAL CONNECTIONS
Approved in conformity with Body R (June 1982 edition) issued by I.S.P.E.S.L.
CE mark in conformity with European Directives EEC 89/336, EEC 73/23.
APPROVALS
Overall dimensions (mm)
a
b
c
2
(a) earth terminals
(b) line terminals
(c) motor terminals
DESIGN FEATURES
Connection
1/4" F
Inner cable gland diameter
11.5 mm max. (for cables H07RN-F-3X1)
Lever mechanism
galvanized steel
Electrical contacts
brass faced with Ag-CdO
Diaphragm
NBR rubber with fabric core
Cover
high impact ABS
TECHNICAL CHARACTERISTICS
Contact load rating
16 (10) A at 250 V ~
Rated voltage
250 V ~
Pressure setting range
1 ÷ 5 bar
Factory setting
3 bar
Max. fluid temperature
90 °C
Degree of protection
IP 40
