old flow check

tank

i have an old htg hydronic system. has been converted over time from gravity to circulators. Question it has old sears #11 flow control valves. customer does not want to replace. What do the settings open/closed/winter, mean. It appears that there is a fine line between closed and winter that will not allow for gravity however not always does the circ. open it up. what do you think? 

icesailor

Old Flo Checks:

I can't remember the brand, maybe Thrush.

But, the "closed" position had the lever all the way down and it wouldn't allow the check to pass water. The "winter" position allowed the check to sit on the seat and stop gravity circulation but would allow circulation when the pump came on. The last setting "Open" meant that the disk was all the way off the seat and water would flow through the system by gravity. Or, could run back to the boiler through the supply if you drained the system.

I haven't seen one in a long time but they are out there.