In order to complete the flushing of the system you have to put some freshwater in the fresh water tank and then run water from each faucet until clear. Just flushing with city water will leave antifreeze on the output side of the water pump. Likewise if you flushed the system with fresh water you would have to run water from the city connection to complete the flushing.
As for the hot water heater you first have to decide if the heater has a bypass valve and was it used by the dealer when winterizing. If the winterizing was done correctly the bypass valve was put in the bypass position and the heater drained via the 3/4 in. plug inside the access door on the outside of the trailer. Look for the bypass valve from the inside of the trailer, generally under the bathroom counter, and make sure it is set to allow water to the heater. If it was not moved to this position before you did the flushing moving it now will allow water to fill the tank. connect to water and fill the tank. This will take about 5 min. and you will have to open a hot water faucet to let the air out.
If there is not a bypass valve you will have to drain the heater via the tank drain because the tank will be full of antifreeze. Once drained connect to water leave the drain open and flush the tank of remaining antifreeze before putting the plug back in and flushinf the hot water side.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles