Use And Care Manual
Operating principle
A spring (1) connected to a float
(2) is located inside the flow meter.
The force applied by the water to
the float as it flows through the
flow meter is countered in
proportion to the force applied by
the spring. When the flow
becomes stabilized at a particular
value, the float reaches a specific
position of equilibrium which also
serves as an indicator. The
system is balanced by moving the
balancing valve on the supply
manifold until it corresponds to the
design flow, which can be read on
the graduated scale printed on the
transparent cylinder (3).
The flow (l/min) readout value
corresponds to the lower edge of
the float.
Installation
The flow meter must always be installed in a vertical position on
return manifold with the flow indication arrow pointing up (7) to
ensure the greatest accuracy when measuring the flow.
Hydronic characteristics
CALEFFI
L/MIN
2
1
4
3
5
4
6
1
2
3
7
(psi) (kPa)Δp (psi)
0.1
1
0.2
0.3
0.5
2
3
5
1
10
2
3
5
20
30
0.4
4
0.1
1
0.2
0.3
0.5
2
3
5
0.4
4
1010
50
50
100
Q (l/h) (
gpm
)
0.2
0.5
200
1
2
Construction details
Easy installation
The flow meter is equipped with a captive nut (4) that is mounted onto the manifold and sealed with an O-ring (5) mounted on the tail piece.
The captive nut solution simplifies assembly because it allows the flow meter to be mounted at the front of the manifold without having to change
the optimal readout position.
Dual readout scale
The flow meter is equipped with a spare graduated scale that can be used if flow needs to be checked or the system rebalanced but the float
can no longer be seen due to deposits on the transparent cylinder.
Turning the knurled nut (6) to the left will bring into view another scale in yellow that always stays clean due to the hermetic seal that prevents
water from entering while the system is operating.
The nut must be returned to the original position on the white scale after reading the measurement.
Series 669
Flow meter with float. 3/4” M x 3/4” F nut threaded connections. Brass body, stainless steel measuring spring, EPDM seals,
transparent cylinder and internal protection in PSU, float-indicator in POM/PTFE. Medium: water and glycol solutions.
Maximum percentage of glycol 50%. Maximum working pressure: 85 psi (6 bar). Max. Temperature for NA Series: 210°F (98°C) and
for 669050: 180°F (82°C). Flow measurement: 0.25 to 1.0 gal/min (1–4 l/min). Accuracy ± 10%. Dual readout scale 1 to 4 l/min.
SPECIFICATION SUMMARIES
Cv = 1.16
Cv = flow in gal/min for a pressure loss of 1 psi
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