The patented Prism Liqui-Fire Liquid Heat Tracing operates on propane or fuel gas to deliver heated glycol to be pumped by our exclusive Prism combustion engineered non-stalling diaphragm pump. The incoming gas pressure operates a split diaphragm pump. One side of the diaphragm is the gas side, and the other is liquid. The liquid side is displaced by the gas filling the gas side, forcing the liquid out through the heat exchanger and heat trace lines. There is a no-stalling micro switch that insures a constant reciprocating operation. The gas circuit is divided and separated from the glycol circuit by the diaphragm so there is no contamination occurring either way. The heavy-duty heat exchanger allows for higher discharge pressures while enabling longer runs of heat tracing. Combine all these features into one proven package and you have the Prism Liqui-Fire Liquid Heat Tracing System.