There are different ways to winterize an RV, some of which may require less anti freeze then the four gallons I generally use, but FWIW here’s my method which I have used for well over thirty years. First of all, I highly recommend a water heater by pass plumbing job which isn’t that hard or expensive to install. If you don’t have one, when you try to run AFZ throughout the hot water piping none flows (only water) UNTIL the 6/10 gallon water heater tank has completely filled with AFZ. That’s such a waste of time and expense if you have to fill 6 gallons of AFZ into the water heater tank before it can flow out the tank and into the hot water lines. NOTE there are methods to use a pressure air line adapter to blow water out the lines, but that can end up with water still in a low point in the system, still use it if you like, it’s your RV.
1) I first drain the fresh water holding tanks. Most have a drain valve somewhere under the RV that’s plumbed to one bottom corner of the fresh water holding tank. I find which corner that is then drive/tow the RV somewhere in the drive or yard or hill ect. so that corner of the tank is at the lowest point so almost all the water gets drained.
2) Of course, I also open the hot water heater drain valve/cock and an inside hot water faucet (for air bleed) to drain the hot water heater completely. Once that’s done I close the drain valve and set the water heater by pass ON so no more fresh water enters the tank, but its instead diverted to what’s normally the hot line output (such is the function of the hot water by pass system).
3) After the fresh water holding tank is empty, I determine which other corner of the tank bottom has the line that leads to the water pump supply/input and I drive/tow the RV so that corner is now at the lowest point.
4) I add approximately 3 gallons of AFZ to the gravity filler opening on the fresh tank top, turn on the water pump, and go to each and every faucet (hot and cold) and open them just long enough that the red AFZ flows out. At first it’s clear water that flows, but as its purged and the pump starts to supply AFZ, it will turn red. The AFZ will also flow down into the sink and lavatory drain traps which prevents them from freezing.
5) Similar to the above, the toilet water system needs to have AFZ all throughout it, so I let it flush/run until the red AFZ appears and a bit is left in the bowl.
6) Once ALL faucets run red with AFZ I use the final 4th gallon to add just a bit to each sink or lavatory drain and toilet to insure the traps are protected, then I add the rest again to the fresh water holding tank top gravity filler. Then I turn the hot water tank by pass OFF so water flows into the tank like normal, turn the pump on and turn on a hot water faucet which forces the remaining AFZ into the bottom of the hot water heater.
7) I then turn the water pump off and open every faucet and put the RV to bed for the winter
8) Finally if you want to use less AFZ then I use above, there are kits sold which you stick a hose down into the RV AFZ bottle and attach the output direct to the water pump input so it flows direct from the AFZ bottle instead of via the fresh water holding tank as I use. The expensive RV’s can have such built in. I believe other kits allow you to reverse pump AFZ into the faucet outlets but that just not my thing.
I also air the tires to their max load at X PSI pressure,,,,,,,,,,avoid the tires being
left on mother earth, cover tires to reduce UV damage, either take the battery
to a safe heated space or connect it to a battery maintainer,,,,,,,,,,,,,if a
motorhome I add a good quantity of gas Stabilizer such as Sta Bil, ,,,,,change the
oil and service filters etc. In addition at least once a month it should be started
and driven if possible and pump the brakes and start the Generator if so equipped
and let it run at least 30 minutes preferably with a load such as the AC fan running.
John T in Indiana Dry Camping Special
2001 Chevy Four Winds 29 ft Class C
454 Vortec with 4L80E Overdrive Tranny
110 Gallons Fresh Water Storage, 80 Gallons gray storage
460 Amp Hrs (4 Golf Cart) House Battery Energy Storage
Xantrex Truecharge2 Smart Three State House battery Charger
200 Watts of Rooftop Solar Panels and Charge Controller
Onan 4 KW Genset