SylvanLMP
Many of the homes I service around here (NYC) were built in 1922 or before.
These have wall hung tanks and or flushometers. The problem with the flushometers is the diaphram/piston type of flushometer has an auxiliary relief valve built into it ( A tiny hole) which can and does get blocked up with sediment. By turning the water off then on your actually flushing this little orifice clean and then the pressure equalizes and shuts off the incoming water by resetting this device.
You should try to get the name of the manufacturer of your flushing device incase you need parts.
