Re: [VACList] Winterizing in Virginia . . .

["Jim W" <jjw@xxxxxxxxxxx>]

Hi Joy,

  My boiler uses propylene glycol also.  The RV antifreeze is a watered down
version of pure propylene glycol.  In Virginia you might even be able to
water it down even more.  A handy little unit is a refractometer from Misco.
It measures the freeze point of the glycol mixture and can also measure the
charge of a lead acid battery.  You can buy highly concentrated PG, and
water it down to your needs.  The only source I know for this sells it for
boilers, and it also includes corrosion inhibitors.  Not something to put in
the pipes.

As an example I am running a 25% solution of PG in my boiler, and Utility
Manufacturing refractometer freeze protection chart says the this will
protect to -50*F.  In Montana that is necessary.  Ice crystals form at
+15*F.  This is how my refractometer is scaled.  The freezing point.  PG is
not an efficient heat transfer fluid, so in a boiler you don't want to much.

In a closed system you will need an expansion tank.  Leaving the faucets
open might work too.  Protection does not mean that ice is not forming, it
just means that the solution can still flow.
I'm still a novice here.  This is just as I understand it after putting in a
boiler baseboard system.  There might be enough air in the pipes to act as
an expansion cushion too.

Since this stuff is not poisonous, and is 3/4 water, beasties might like it.
I do have a sample that was exposed to air and has been sitting in a jar for
two years.  Still as clear as the day I put it in.  I would be interested to
hear more about this.

Jim Widdicombe