Re: [A/S] Winterizing (Please, please don't put it in the tank)

[Charlie/Betty Burke <cbburke@xxxxxxxxxxxxx>]

This particularly nasty bit of advice has been running around for so 
long it qualifies as an urban legend. Worse yet Trailer Life/Motorhome 
still mention it.
Most RV fresh water plastic tanks used on the modern demand systems do 
not have a bottom drain. Most Airstreams do but it is hard to get to and 
often ignored. The most common drain is in the side of
the tank 1/2" or more above the bottom including Airstreams. If one 
relies on the side drain to empty the tank, it will not completely do 
the job.
If one dumps RV antifreeze in the tank to winterize he/she is dumping it 
into several gallons of fresh water thereby diluting it. Rule 1 of RV 
antifreeze is DON'T dilute it. So if you dump it in the
tank you have significantly reduced you protection. After winterizing 
with this diluted mix there will be some of it left in the tank. Even if 
it completely evaporates over the winter, there will be
residual chemical in the tank. When you add fresh water in the spring 
you reactivate the stuff. And while it is non-toxic that doesn't mean it 
tastes good. In fact it is pretty nasty. It can take
several rinsing to get the taste out of the tank. The problem is more 
associated with the tank than the plumbing because the inside of the 
tank is rough and pitted while the plumbing is extruded and
very smooth inside.
So, the recommended way to winterize is to draw it in through the water 
pump and bypass the water tank all together.

Charlie