[Dave in Va]

Originally Posted by JRTJH

Packed2go,

If you think about the way the city water inlet is constructed, if you use air to blow out the water, then use the water pump to fill the lines with antifreeze, the antifreeze will backflow to the check valve that is located immediately behind the garden hose connection. There's really no reason to "burp" the fitting. Doing so can (not always) dislodge the oring seat causing the check valve to malfunction. It can occasionally be repositioned, but often the check valve has to be replaced to make the system function normally.

Almost always (I've never seen a failure) if you use compressed air to purge the majority of the lines, it will remove nearly all the water from the city water inlet. Then when you pull the inlet fitting on the water pump, gravity will clear the line from the tank to the pump. Attaching the antifreeze draw line and pumping antifreeze into the system will backflow antifreeze into the check valve as it flows throughout the remaining lines as well. As you open each faucet (hot and cold) and see pink flowing, that fixture is protected. Don't forget the outside shower and the toilet. Then pour about 1-2 cups of antifreeze into each trap and you're done inside.

That only leaves the black tank flush. I always use air to rid the line of water, then remove the anti-siphon valve. Gravity will take care of the rest of the water in the two halves of that system.

Don't forget to empty your holding tanks completely. I always leave my valves open, that way water can't accumulate in the lines from the tank to the valve and freeze/crack them. Others leave their valves closed and pour some antifreeze into each tank. I prefer to leave them dry, but either is OK as long as you are sure there's no water in any of the lines.

Good Luck with your winterizing.

Good info here...