... pipeline, make sure it has hot water when turn on the tap.6 Exhaust temperature protection: stop the ... External alarm function: one-way external switch alarm signal output, can set into “On”, “Off” and “Forbidden”, set ... °C and environment temperature is below 0°C, turn on heat pump to heat the water, when the ... 50%, first supplement the water to 50% then turn on heat pump to heat the water to the ...