Product Overview
1
A
B
C
Application diagrams
Caleffi panel radiator valves are designed to be installed on panel 
radiators featuring connections both on the bottom and an externally 
invisible inner pipe, which feeds the flowing medium to the upper valve.
They come in two versions: for two-pipe and one-pipe systems. Both 
are available straight (pipes exiting the floor) and angled (pipes exiting 
the wall). The two-pipe version is equipped with two ball shut-off valves; 
the one-pipe, in addition to the shut-off valves, is equipped with an 
adjustable by-pass from 30% to 50% of the flow rate towards the 
radiator, and a thermal break device (1) that prevents thermo-syphoning 
upward into radiator from by-passing flow.
Since the radiators are in series in one-pipe systems, the downstream 
radiator receives water at a lower temperature than the upstream 
radiator. In most applications, it is recommended the number of 
radiators should be limited to 3 to ensure sufficient heat delivery.
Isolation valves and diverter valves are not necessary when directly 
connecting a panel radiator to manifold. Radiator adapter, code 
940451, is used for direct pipe connection, PEX, PEX-AL-PEX, sweat or 
compression, to the radiator.
How to adjust the by-pass on 
single one-pipe valves. Range: 
30–50%
The valve is supplied preset with 
35% flow rate to the radiator. To 
change the flow rate, shut the 
by-pass valve and then unscrew 
the same by a number of turns 
equivalent to the required flow 
rate indicated in the graph.
One-pipe plumbing
Two-pipe plumbing
Manifold piping
(A) Diverter valve (3012, 3013)
(B) Isolation valve (3010, 3011)
(C) Radiator adapter, code 940451
2 3456
25
30
35
40
45
50
55
2.5 3.5 4.5 5.5
Number of turns 
Flow rate %
6mm
2 3456
25
30
35
40
45
50
55
2.5 3.5 4.5 5.5
Number of turns 
Flow rate %
6mm
Code Description
449740 Plate
Code Description
940451
1
⁄2" M radiator x 
3
⁄4" M conical pipe
4497
Wall-covering plate. 
For dual panel radiator valves 301. 
With wall connections. 
In white ABS. 
Outlet center distance: 40–50 mm
940
Radiator adapter for directly 
connectingapanel radiator to a 
manifoldwith PEX, PEX-AL-PEX, 
sweator compression fittings.
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