I have been doing it for 20 year. Fill the empty hot water tank to 40 psi and then go inside and drain one tap at a time. Repeat twice and Viola done. Up to minus 40F here in winter. Do not forget W/D tapes and pump lines. Starting pump while connected to city connection could drain pump and blowing in the flushing liquid suction line if equipped may work.
Barbara and Laurent, Hartland Big Country 3500RL. 39 ft long and 15500 GVW.
2005 Ford F250 SD, XL F250 4x4, Long Box, 6.0L Diesel, 6 Speed Stick, Hypertech Max Energy for Fuel mileage of 21 MPusG empty, 12.6 MPusG pulling the BC. ScangaugeII for display..