Originally Posted by us71na
I would be concerned about just using compressed air because there may be enough water left in the lines to settle to the low point in the lines and freeze. You need to blow a large volume of air through the lines to get all the water out. A portable 12 volt compressor for inflating tires isn't going to provide enough air volume to adequately blow out the lines. As others have stated $10 of antifreeze is cheap insurance compared to the cost of replacing water lines.
Even if you blow out the lines and drain the hot water tank, you still have water in the sink and shower drains that will freeze unless it is displaced by antifreeze.
You can use slightly less anti freeze if you blow out the lines first.
We've kind of beat this one to death. Either way or combination of both works. I prefer the compressor method and have done it for over 10 years on 2 campers and a houseboat without any problems. Have to take issue though with the concern you raise about needing a bigger compressor. Simply not true. A small compressor works just fine as you don't want to over pressurize the lines. The little ones set not to exceed 20 or 25 psi do great. Just hook it to the city water intake valve, turn it on, and then go from one faucet to the next, opening each one until it stops pushing out water. I make a complete pass on all of them, then recheck the low point drains in case water may have drained into them. Close the lowpoint drains and go thru the process a second time. I like to start with the faucets that are farthest from the water input and work backwards.
think its time to move on with this thread. Starting to sound like people arguing politics and no one is going to have their mind changed. My only reason making this last post, is to correct inaccurate statements that have been made. Don't use the air compressor method if you prefer the pink stuff. This is afterall still America [or maybe Canada for some].