___ certification is required for technicians servicing low-pressure appliances that use a refrigerant that boils above 50°F at atmospheric pressure.

Suction lift is the pressure at a pump inlet when the liquid supply to the pump is taken from a tank or other supply source that is above the pump.

___ certification is required for technicians servicing low-pressure appliances that use a refrigerant that boils above 50°F at atmospheric pressure.

A reciprocating compressor is a compressor that has reciprocating cylinders to compress refrigerant.

In the combustion process, approximately 75 lb of air are required for every pound of fuel burned.

A firebox boiler is a cylindrical scotch marine boiler.

A flammability hazard on the NFPA Hazard Signal System indicates the degree of susceptibility of materials to explode or release energy by themselves or by exposure to certain conditions or substances.

A reciprocating compressor is a compressor that has reciprocating cylinders to compress refrigerant.

The location of an auxiliary low water fuel cutoff allows it to act as a backup if the primary low water fuel cutoff fails to shut the burner OFF in a low water condition.

A feedwater ___ valve is located next to a feedwater stop valve and prevents feedwater from flowing from the boiler back to the feedwater pump.