2
Watts Water Technologies, Inc.
Description
Approvals
Application
FLAMSTOP
1/2” and 3/4” liquid and gas fuel shut-off valves, suitable for biodiesel. Positive action
with manual resetting. Liquid expansion thermostat. Compact sensor. 1/2”M sensor
sheath connection (with 1/2”F x 3/4”M nipple).
INAIL approved and set. Compliant with
Directives PED 2014/68/EU and ATEX 2014/34/EU.
NVFN
Type
Part No.
DN
bar
NVFN
0231415
1/2” FF
10
NVFN
0231420
3/4” FF
10
NVFN
0231425
1” FF
10
NVFN
0231432
1.1/4” FF
10
NVFN
0231440
1.1/2” FF
10
NVFN
0231450
2” FF
10
NVFN
0231465
65
10
NVFN
0231480
80
10
According to the provisions of R regulations Ed. 2009, the technical specification for the application of Title II of Italian Ministerial
Decree 1/12/75 pursuant to art. 26 of the said decree concerning "central heating systems using pressurised hot water at a
temperature not exceeding 110°C and maximum overall rated power of the space heaters (or maximum overall heat output
of the space heaters) greater than 35 kW", the use of fuel shut-off valves is required in the following cases: systems with
closed expansion vessel (CHAP. R.3.B., point 1., letter b); closed-vessel systems with heat exchangers supplied with fluids
at temperatures exceeding 110°C to the primary circuit (CHAP. R.3.D., point 2.2.1., letter g); - systems with modular boilers
(Chap. R.3.F.).
Technical features
Setpoint temperature
97°C (±3°C)
Maximum temperature, sensor side
120°C
Maximum temperature, valve side
50°C
Maximum operating pressure
6 bar (NVFN 15-25) - 1 bar (NVFN 32-80)
Fuels
Diesel, fuel oil, natural gas, propane, butane
Capillary length
5 m
Minimum storage temperature
-40°C
Operating range
10-100°C
Minimum temperature, valve side
-5°C
Minimum temperature, sensor side
-15°C
Features
Body
Die-cast aluminium (NVFN 15-50) - Cast aluminium (NVFN 65-80)
Seals
FPM (NVFN 15-20) - NBR (NVFN 25-80)
Disc spring
AISI304 stainless steel
Capillary
Electrolytic copper
Heat-sensitive element
Liquid expansion
Connections (1/2” to 2” models)
FF threaded gas (ISO 228/1)
Connections (DN65 and DN80 models) PN16 flanged (UNI 2223)
Test points (1/2”-2” mod.)
Qty. 2 x 1/4”
Test points (DN65 and DN80)
Qty. 4 x 1/4”
Heat-sensitive element sheath connection G 1/2”M (ISO 228/1)
N.B. The NVFN15 and NVFN20 models with FPM seals can also be used for biodiesel.
Approved to “R” regulations (2009 edition). Calibration certificate issued by lNAIL.
In certain cases, INAIL regulations (R regulations, 2009 Edition) governing systems with boilers with heat output exceeding
35kW, require the use of a fuel shut-off valve in place of a thermal drain valve. They define a "fuel shut-off valve" as: “a positive-
action valve, which automatically shuts off the flow of fuel if the water overheats, so that it does not exceed the established
safety temperature”. The fuel shut-off valve is a self-operated positive-safety device (operating without the use of external
energy).