The following table gives, for the various pipe diameters, the relative blade lengths
to be adopted and relative min. and max. load capacities for reversing the contact.
The values given refer to horizontal installations.
B* - C* - D* = cut blades
The drawings shows the traces to be followed for cutting the blades in order to
obtain lengths suitable for the various pipes.
FS25
Flow switch for liquids, for
piping from 1" to 6".
Can be used in moist
environments.
1505825 1”
IP55
Part No. Size Protection
The FS25 series refers to a flow switch which interrupts
the electric control circuit of the burner when there is
insufficient water circulation in the boiler circuit owing to
some abnormal condition (e.g. stopping of the motor-dri-
ven pump). The FS25 series flow switch is operated
thanks to an electrical blade-type tripping device (stain-
less steel blade) and can be installed on pipework from 1"
to 6" in size.
APPLICATION AND OPERATION
Mount so that the direction indicated by the arrow
coincides with the flow.
For correct operation it is advisable:
- to mount on the return pipe
- to mount on horizontal pipe (mounting on vertical piping
is possible after appropriate setting)
- to keep a certain distance from sources of turbulence
(elbows, valves, etc.); recommended min. distance is
equal to 5 times the pipe diameter
- to keep a minimum distance of 55 mm between the
pipework and the lower base of the appliance.
INSTALLATION
The 1-2 contact is normally open (closes when the flow rate setting is reached);
contact 1-3 is normally closed (opens when the flow rate setting is reached). Earth
connection is through relative screw located at the bottom on the microswitch
support.
ELECTRICAL CONNECTIONS
UL/CSA approval.
CE mark in conformity with European Directives EEC
89/336, EEC 73/23.
APPROVALS
ADJUSTMENT OF FLOW RATE SETTING
Overall dimensions (mm)
1”
28,5
A
1,2
0,5
2,6
1,9
1”
1/4
41
A + B*
1,8
0,8
4,0
3,3
1”
1/2
44
A + B*
2,3
1,2
4,0
3,4
2”
54
A + B
3,0
1,8
7,8
6,6
2”
1/2
70
A + B + C*
4,8
2,3
12,2
10,8
3”
82,5
A + B + C
6,8
2,7
11,8
10,5
4”
108
D*
8,9
4,3
16,7
14,5
5”
133
D*
13,2
6,6
26,1
20,9
6”
159 D
17,9
9,0
37,7
27,9
DESIGN FEATURES
Casing and cover
Die-cast aluminium
Blade
Stainless steel
Bellows
Phosphor bronze
Fitting
Brass, 1" M
Cable entry fitting
1/2" NPTF
TECHNICAL CHARACTERISTICS
Contact load rating
20 (8) A at 250 V ~
Max. fluid pressure
10 bar
Max. fluid temperature
140°C
Degree of protection
IP 55
A
1”
28,5
44
41
54
70
82,5
133
108
159
3”
4”
5”
6”
2”
1”
1/4
1”
1/2
2”
1/2
B
C
D
NORMALLY
OPEN
NORMALLY
CLOSED
Tube Blade Blade
Flow rate with
Flow rate with
diameter
length
combination minimum setting
minimum setting
(screw fully tightened) (screw fully loosened)
(inches)
mm
m
3
/h
m
3
/h
contact contact contact contact
close re-open
close
re-open
