The VRA/VLA/VTA types are normally closed solenoid valves for cold combustion air regulation
(open when energized). This type of device is suitable for high/low control of combustion air in
industrial gas burners.
The valves are made of aluminum alloy die-cast, with a wide range for inlet/outlet connections
from DN 20 (3/4” )up to DN 80 (3”).
Pipe connections meet group 2, according to EN161 requirements.
Suitable for use with cold combustion air (not for safety shut-off).
Provided with two flow adjustments: minimum and maximum flow rate, for high/low operation.
Suitable for heavy-duty cycle operation and for continuous service (100% ED).
The whole range can be provided in Ex-proof execution, for use in Zones 2 and 22, according to
2014/34/EU Directive (ATEX).
The valve is supplied without an internal filter, because in many applications the air is very dirty
and it should clog the filter in short time. It is provided with a special dust cover able to protect
mechanical moving parts.
Provided with 1/4” pressure gauge on two sides in the inlet chamber, to connect manometers,
pressure switches or other equipments. Flanged models are provided with gauges also in the
The coils are provided with terminal box or with ISO 4400 plug (optional). Both systems are
provided with suitable cable gland to avoid water and dirty contamination.
All components are designed to withstand any mechanical, chemical and thermal condition
occurring during typical service. Effective impregnation and surface treatments have been used
to improve mechanical sturdiness, sealing and resistance to corrosion of the components.
Valves are 100% tested by computerized testing machineries and are fully warranted.
The VRA type valve is a fast opening/closing solenoid valve. The VLA type is a slow opening an
fast closing solenoid valve. The VTA type is a slow opening/closing solenoid valve.
Both Min./Max. can be set from 0 to100%.
When not energized the spring works on the disc keeping the minimum passage of air. When
powering the coil the valve opens, moving the disc to the maximum open position. When power
is switched off the valve moves to the minimum position.
Connections Gas threaded ISO 7-1 from Rp3/4 to Rp2½ or
ANSI-ASME B1.20 from 3/4”NPT to 2”½NPT
Flanged PN16 – ISO 7005 from DN40 to DN80 or
ANSI-ASA-ASME B16.5 class 150 from 2” to 3”
Voltage rating 230 VAC 50/60 Hz
120 VAC 50/60 Hz
110 VAC 50/60 Hz
Voltage tolerance -15% / +10%
-15°C to +60°C (+5°F to +140°F)
Max. operating pressure 200 mbar (3 psig)
Operating time VRA: 1s opening/closing
VLA: ~4s opening / 1s closing
VTA: ~4s opening/closing
Protection class IP54 (NEMA 3)
optional IP65 with cable (NEMA 4)
Cable gland M20x1,5 for terminal box
PG 9 for ISO plug
Wires cross-section 2,5 mm2 max. (AWG 12) for terminal board
1,5 mm2 max. (AWG 14) for ISO plug
Electrical safety Class I (EN 60335-1)
Coil winding insulation Class H (200°C, 392°F)
Coil thermal resistance Class F (155°C, 311°F)