Safety pressure switch

A heater assembly for use with one of a first fuel type or a second fuel type different than the first, the heater assembly comprising:

• a burner;
• a pressure regulator unit configured to regulate either a fuel flow of a first fuel type within a first predetermined range or of a second fuel type within a second predetermined range different from the first, the pressure regulator unit comprising a housing having first and second fuel hook-ups, the first fuel hook-up for connecting the first fuel type to the heater assembly and the second hook-up for connecting the second fuel type to the heater assembly;
• a pilot nozzle;
• a temperature sensor;
• a control valve for controlling the flow of said first type of fuel and the flow of said second type of fuel to said burner;
• a pressure switch communicating with one of said first and second fuel hook-ups, wherein when fuel has a pressure below a threshold said pressure switch permits said temperature sensor to electrically connect with said control valve and when a fuel has above said pressure threshold said pressure switch prevents said temperature sensor from electrically connecting with said control valve.