Hwa Young Liquid LPG Automatic ChangeOver Regulator (HLX-301)

Automatic Changeover regulators prevent gas outages by switching supply cylinders over to the reserve cylinder automatically when the primary cylinder is near empty. When the primary cylinder is depleted causing the changeover to occur a red indicator will appear signifying the reserve cylinder in now in use and the primary cylinder can be refi lled without loss of service.

Reduced the damage from the deterioration by metal abrasion, even though use valve often frequencies.

This regulator equipped convert handle which indicates “serve“ and “reserve”, and diaphragm operation would help adjusting demand pressure.

This compact designed for especially space limitation, and light weight helps to easier installation.


Model HLX-301A
Service Liquefi ed Petroleum Gas (LPG : Liquid Condition)
Max. Capacity 300 kg/h
Inlet Pressure Range (Changeover Pressure +△P) ~1.56 MPa (15.6 kgf/cm²)
Setting Changeover Pressure 0.05 ~0.2 MPa (0.5~2.0 kgf/cm²)
Internal Pressure 3 MPa (30 kgf/cm²)
Inlet / Outlet Connections 20K-20A Flange
Inlet / Outlet Length 315mm X 170mm
Weight 9.1kg

About inlet pressure △ P, Please refer to below table
Capacity (Kg/hr) 100↓ 100~150 150~200 200~250 250↑
△P (kgf/cm²) 0.03 MPa (0.3 kgf/cm²) 0.07 MPa 0.07 MPa (0.7 kgf/cm²) 0.11 MPa (1.1kgf/cm²) 0.14 MPa (1.1kgf/cm²) 0.18 MPa (1.1kgf/cm²)
Example) in case of changeover pressure 0.05MPa, Capacity 190kg/h 0.05+0.11=0.16 MPa (changeover Pressure +△P)

* Outlet pressure is adjustable by setting the length of adjusting screw. When it’s needed, Please refer to the below table.
Setting Interval 21mm 16mm 12mm 7mm
Setting Changeover Pressure 0.05 MPa (0.5 kgf/cm²) 0.1 MPa (1 kgf/cm²) 0.15 MPa (1.5kgf/cm²) 0.2 MPa (2kgf/cm²)

* Note that this product approved performance from Korea Gas Safety Corporation.
The warranty is a year from customer purchased.

Adjusting pressure

1. Automatic changeover device equipped two types of spring which allows accurate and comfortable control the demand pressure.
2. Regulator apply pressure range from 0.5 to 2.0kgf/cm², if require to adjust demand pressure, please check adjusting knob length.
3. To adjust demand control, there is a pressure control screw either turning to clockwise or counterclockwise. Be sure that adjusting knob provides various pressure demands, and suitable pressure has been released.




A indicates serve, and B indicates reserve

Figure 1
Pressure from A is lower than demand pressure which means that changeover operates properly. Therefore, gas flows from B. ( At this time, indicator shows red)

Figure 2
Reserve provides gas to regulator at this moment. To close valve from A, turn convert handle to B which allows replacing new gas cylinders for A. (indicator shows red to colorless).

Figure 3
The other Pressure from B has lower than demand pressure now, so that A supplies gas to the regulator. (indicators changes from colorless to red).

Figure 4
Gas provided from the A, as same operation as fi gure 2, to close valve from B, turn convert handle from A to B which allows refi lled the gas cylinders for B



  • Replacing a gas cylinder, must inspect the indicator and follow below procedure.
    1) When indicator turned in red, (assuming indicator direction is serve) gas is being supplied from the reserve cylinder.

    2) Closing service valve and high pressure pipe valve, and turn convert to opposite.
    3) Note that do not replace a gas cylinder without procedures above.
    4) Replace a new cylinder after inspection has been made.
  • After replacing a new cylinder, MUST check an indicator turned to colorless. If indicator still remains red, slowly redo the procedure above.
  • After all pressure has been released from the regulator, check an indicator point to proper direction (either serve or reserve), then inspect that there is a gas leak in the cylinder valve, inlet fitting, high pressure hose, or regulator seat.
  • Do not attempt to load any heavy matters on the regulator for safety issue.
  • Do not attempt move or place a cylinder when connected with high pressure hose.

Manual changeover

* User can change from reserve or serve manually if indicator function in case of not working properly.
  • Colorless of indicator means serve, however, it may be unreleased gas from the serve. In this problem, push manual changeover button to release gas fl ow properly.
  • At the time pushing manual changeover button, indicator turns to red mark. This procedure makes to change from “serve” to “reserve”.
  • Must turn convert handle to opposite direction, after indicator appeared red mark.


* Do not attempt to push manual changeover knob with hammer.
** Do not keep pushing knob during processing.

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