With anti-freeze they usually shut off auto-feeds and auto air bleeds.Feeds because don't want to degrade anti-freeze and bleeds because crude grows in such places.Strength of anti-freeze needs to be checked now and then asked techs.for best advice.
Old Guy
January 2012
I can answer this question...
I have a 10 year old Burnham boiler hydro air system?
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.