I have a hot water baseboard oil fired system. I am going away for a while and would like to shut off the cold supply to all the house in case of a water leak. If I leave the furnace on to heat the house, will shutting off the cold water supply to the furnace be a problem?
I was told by my oil delivery company that my baseboard system is a closed one and does not replenish itself. I have not had the time to investigate the system fully, including whether it had ever had antifreeze added, but I will get to it eventually; two years into this house, and that is still a low priority project.
That said, I did believe the oil company enough to shut the water off to the house, and to the boiler, each time I have traveled since moving into this house, including a recent two week vacation. I have seen no deleterious side effects from shutting the water off. My advice is to call whomever services your boiler and ask them; as I did.