Shut off valve to hot water heating system... Closed or Open?

[Deleted User]

I have antifreeze in my hot water heating system... Should i close the feed shut off valve or keep it open? Thank you in advance for your help...

Thanks
Mike

Al Letellier_9

open or closed

If you have the proper protection devices on the boiler, it doesn't matter. You should have a dual check, reduced pressure zone backflow preventer and a low water cut-off on the feed line and the boiler. Do not shut off the supply if there is no low water cutoff on the boiler. Antifreeze can create leaks where water won't. Make sure and have it tested annually for corrosiveness and freeze protection.