In sub-zero temperatures a motorhome heater can shut down even when the gas cylinder is half full. The cause is the difference between butane and propane: butane stops vaporising at around -0.5 °C, while propane remains usable down to -42 °C. Gas supplier Antargaz advises against butane when the cylinder temperature falls below 5 °C. In LPG mixtures the share of butane in the remaining liquid rises as propane is consumed, which can lower pressure. Manufacturer Trumaⓘ warns that moisture in LPG can form ice crystals around freezing point and block the pressure regulator.
