Using air will never remove all the water outโฆ whatโs left will settle and pool and freezeโฆ leaving the valve open to mitigate problems would work if water only froze along the path of least resistanceโฆ it donโt it expands in all directionsโฆ
The low point drains are only the low point if time is devoted to leveling the unit firstโฆ front to back/side to sideโฆ then only maybeโฆ
Most compressors people use for this have the pressure required for a short time, but not the volume of air needed to blow the lines outโฆ it is the volume of air at pressure that moves the residual water along the lines to the faucetsโฆ that volume of air needs to be maintained for some time to declare the lines dryโฆ
While pumping the pink through it doesnโt mix with the water much at allโฆ it pushes the water through and clear runs out the tap until the pink arrivesโฆ the percentage of dilution is miniscule and not much of a problemโฆ
The only best method is to blow the lines out, then flood with the pink stuffโฆ if you donโt like the pink setting in thereโฆ blow it out then toโฆ the traps are then filled with the pink stuff from the pipes, and residual left in the pipes is AF and you really have nothing to worry aboutโฆ we are only talking about a few moments more time and a few dollars to be sure instead of luckyโฆ
I have repaired or helped repair many broken lines winterized with air only and never one had to do one with AFโฆ
Also every fall the air only proponents make recommendations for air only, and every spring we read the broken or leaking waterline postโฆ I guess there is no correlation there thoughโฆ
Maybe the air only proponents that say done properly could expand on what properly means to add value to their claimsโฆ they seldom doโฆ
Edit:
Of the three guys I know that do literally hundreds of winterizations each for a fee, none will do them without using AF, unless a release of damage is signed firstโฆ
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Love my mass produced, entry level, built by Lazy American Workers, Hornet
