Properly setting your dispensing station’s bypass valve is a key step in having a well functioning system. A properly set bypass valve will help relieve undue stress on your pump, extend it’s life, and reduce cylinder fill times. Here are some basic steps to properly set up a Corken B166 Bypass Valve.

  1. Check to ensure the bypass valve is installed in the proper location within the pump’s discharge line.
  2. Open all valves. Start with bypass and meter vapor return lines (if a meter is used) to pressurize the pump prior to opening the liquid supply line.
  3. Turn the adjustment screw on the top of the Corken B166 Bypass Valve with a wrench counter clockwise to loosen it until it turns freely by hand and is not putting any pressure on the spring. Do not remove it completely.
  4. Double check that you've turned the pump off then record your tank pressure.
  5. Turn on the pump and let it run for a minute. Record the system differential pressure at the pump gauge while it’s running and recirculating full pump capacity through the bypass line. You may also attach the discharge hose initially to the tank’s fill valve to circulate the gas, ensuring full liquid flow through the piping system.
  6. Turn the bypass set screw clockwise until the pump’s differential pressure is between 65 and 80 psid. Try to be on the high side for motor fuel tanks and go lower for standard cylinder filling. Once set, be sure to tighten the locknut to hold the set screw at that setting.
  7. After setting the pump differential pressure, be sure to do an amperage test on the incoming electrical wires for the motor to ensure it does not exceed the FLA (full amperage load) as indicated on the motor’s data plate. If the amperage and/or voltage is higher than indicated, you will have to check the wire sizes and distances from the motor to the electrical service connection.
  8. Do not exceed the maximum design pressure of the pump in your system. Corken models C, F, DS, and DL have a maximum pressure of 125 psi. Other pumps have different maximum differential pressure ratings so be sure to know the pump you are working with.

Corken Wire Size Chart

Another important part of a proper bypass system is the return line and where it connects to the tank. There are a couple dispensing and/or autogas specific tanks on the market with an additional opening for the bypass lines that are a great option. However, the standard 1000 gallon domestic tank is the most common tank used across the country for basic pump station installation. Firstly, using the POL connection as your pump’s liquid return connection is not the way to go. That has a restricted opening and will put undue stress on your pump. You also do not want to use the tank’s liquid withdrawal valve (Chek-Lok) opening. That may be needed at some point down the road to evacuate the tank and, more importantly, that is a liquid connection with an internal dip tube to the liquid space of the tank and you always want to have the pump’s bypass line dump into the vapor space of the tank. This leaves the fill valve opening. The best way to return your pump’s liquid bypass line to the vapor space of your standard 1000 gallon AG domestic tank is to remove the 1-¼” NPT fill valve and replace it with a Multipurpose Valve. The RegO model 8118P Multipurpose Valve can be used as a replacement for the standard fill valve.

The RegO 8118P provides you with the standard fill valve capabilities into the vapor space plus it includes an additional 1” NPT opening for connecting your bypass line. This LP Gas designed valve includes an excess flow and fill valve. This valve comes equipped with an upper check and manual shut off. There is also a ¼” NPT plugged gauge port. These features make this valve the perfect fit.

Having a properly designed and functioning liquid bypass system on your dispensing station will help ensure longer pump life and less wear and repairs dues to excess system stress.