Hiwi Double stage Pressure regulator + SV & CV

Hiwi Double stage Pressure regulator + SV & CV

  • Can be used in combination with returnable cylinders
  • Suitable for use with inline atomizers
  • Constant CO2 supply until the bottle is empty
  • Solenoid valve and check valve are screwed tight
  • Facilitates precise adjustments to the CO2 supply
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This high-quality pressure regulator is used to reduce the pressure of approx. 54 bar within the gas cylinder to a working pressure of approx. 1 to 3 bar (maximum working pressure 3 bar). By combining the working pressure manometer and the cylinder pressure manometer you can regulate the CO2 supply very precisely and you know at once when it is time to refill the cylinder. The integrated fine needle valve allows a very precise regulation of the CO2 supply for the aquarium. Thanks to the double chamber system, the working pressure remains constant until the cylinder is completely empty.

When pressure regulators without a double chamber system are used the working pressure may rise relatively fast and abruptly as soon as the gas filling inside the bottle goes below around 20% of the nominal filling quantity. If you do not re-adjust manually in such a case, the amount of CO2 supplied to the tank will increase significantly and surmount the dosage that was originally set. If you do not want to take on this task, the remaining 20% of CO2 would need constant adjustements of the working pressure.

With this double-chamber pressure regulator, on the other hand, the cylinder can be emptied almost entirely without the need to adjust the working pressure for the last 20% of CO2, which is of advantage especially when you use large CO2 cylinders. In a 10 kg cylinder, e.g., around 2 kg of CO2 would need constant adjustments regarding the working pressure.

Please keep in mind that all components of the pressure reducer have been glued together by the manufacturer. These can not be unscrewed without damaging them. If the needle valve is removed, the manufacturer's liability will expire prematurely. The hose connection on the fine needle valve is an exception. This is not glued in due to the fine thread, so that in the event of a defect, it is not necessary to replace the entire fine needle valve but only the hose connection.

This pressure regulator from Hiwi is also available without solenoid valve (SV) and check valve (CV): Hiwi Double Stage Pressure Regulator

The Hiwi Double Stage Pressure Regulator is also available with one pressure chamber, a fixed solenoid valve (SV) for night shut-off and with a ceck valve (CV): Hiwi Pressure regulator + SV & CV

Manual (in German Language) - - download PDF


  • The pressure regulator is designed for returnable cylinders
  • Thread: W21,8 x 14G
  • Seal included
  • The thread is made according to UK, Europe, Japan and Taiwan standard (BS341 / DIN477 / W21.8)
  • The connection for the CO2 tubing is equipped with a metric thread (M6)
  • High-quality solenoid valve with low energy consumption. The solenoid valve is firmly attached to the pressure regulator.
  • 1,5 m power supply cord with German plug
  • Power supply: 230 V AC; 50/60 Hz; 1,6 VA open
  • Closed when without current
  • 100 % ED (suitable for continuous operation)
  • Permissible temperature: -30 - 130 ºC
  • Max. ambient temperature: 40 ºC
  • Protection class IP65 (dust-proof and protected against jets of water)
  • Insulation class F (155 °C) screwed to plug
  • Max. pressure difference: 16 bar
  • A check valve secures the entire CO2 supplying system. It is firmly connected with the solenoid valve and the pressure regulator
  • With German instructions of use


Please use the pressure reducer only after reading the operating instructions, which are linked above.

  • Make sure that you really start the pressure reducer with a CO2 bottle.
  • Turn the working pressure adjustment screw (operating instructions 4) counterclockwise.
  • Close the fine needle valve (operating manual 5) by turning it clockwise. CAUTION: Tighten only slightly!
  • Position the pressure reducer so that the pressure gauges are facing upwards.
  • Fasten and tighten the pressure reducer to the CO2 cylinder using the union nut (operating instructions 7).
  • It is essential to ensure that the seal is correctly seated and that the sealing surfaces are clean. If the seal is is damaged or lost, please replace it.


Hiwi Double stage Pressure regulator + SV & CV
Width 210 mm
Height 170 mm
Depth 100 mm
Meas. from connection 155 mm



Hiwi is a renowned German manufacturer of CO2 pressure regulators. The highest level of quality and a long useful life are in their focus. These high quality standards do not exclude attractive prices, though.

Especially in aquascaping, the addition of CO2 for the plants is something very basic, and thus it is really important to choose good CO2 supplying equipment. Hiwi meets even the highest quality standards in every aspect und is thus the best choice when it comes to CO2 pressure regulators.

General information

Item no.
Weight 3,00 kg
Shipping weight 5,20 kg

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