I have used these procedures successfully for 15 years. Sorry for the length.
Some locations and details will be different. Hope this helps. I hope I didn't leave anything out.
Trailer Winterizing Procedure
1. Empty fresh water tank. Valve is near back driver’s side tire underneath the trailer. Leave valve open all winter.
2. Remove access panel inside cargo area giving access to back of hot water heater.
3. Turn winter bypass valve on hot water heater to bypass setting. Yellow lever switch at back of water heater.
4. Empty hot water heater. Remove white screw in plug on outside bottom on heater and open pressure relief valve at top of water heater.
5. Turn water pump intake valve to external setting.
6. Pour 4 gallons of pink antifreeze into a clean bucket.
7. Place water intake hose in bucket.
8. At EACH tap, run water until pink antifreeze comes through.
HOT & COLD
1. Kitchen taps
2. Bathroom sink taps
3. Bathroom Toilet
4. Shower taps
5. Laundry room taps (bottom right hand cabinet at foot of bed, right of closet mirror doors)
6. Pour some antifreeze into each trap.
7. Outside taps (in cargo area adjacent to hot water heater)
Spring Sanitizing & Startup
For Citation 31CKDS (1 ½ cups bleach for 232 Litre tank)
Then (3 cups backing soda for 232 Litre tank)
¼ cup of plain bleach (not scented bleach) per 15 gallons water
- Flush all lines with fresh water first
- Mix required bleach in with about a gallon of water
- Then pour into holding tank
- Then fill up holding tank
- Ideally, take trailer for a drive to slosh tank around
- Open winter bypass to hot water tank so solution fills hot water tank as well
- Turn on water pump
- Open all taps to run solution into pipes, don’t forget hot water tank, outside shower and toilet lines, run about 1 litre of water out of each tap
- Let sit for several hours
- Drain system and hot water tank.
- Fill system with fresh water
- Flush system again
- Mix ½ cup backing soda with a gallon of water (per 15 gallons of holding tank capacity) (mix and dissolve well)
- Pour into holding tank
- Fill holding tank
- Run about one litre of water out of each tap again don’t forget hot water tank, outside shower and toilet lines
- Let sit for a few days
- Empty system
- Fill and flush several times
2005 Chev 3500 Duramax/Allison Ext Cab SRW 4x4 Long Box
Blue Ox Bedsaver, Hawkshead TPMS, Rear View Camera System
2007 Citation Supreme 31CKDS
220 W solar, 2800 W Magnasine pure sinewave inverter/charger/battery monitor, 4x6 volt deep cycle, Rotochoks