Here's hoping for a "simple" fix. I turned on the shower faucet (single handle) to the usual position where i like the mix of hot/cold and "nothing" came out. I turned it further (about another 1/4 turn) and water did come out but it was too hot so i turned off the faucet. I turned it on again and this time no water came out no matter how far i turned the handle. I turned it off completely and now there seemed to be a drip. Over the last hour, that drip has turned into a slow, but steady water stream. It actually is filling a gallon bucket every 10-15 minutes. The water emerging is hot water. I live in a 5 unit condo complex where each unit has it's own gas fired water heater in the basement. The "life expectancy" on my water heater is past date but nothing seems to be wrong with the water heater. Can anyone answer the dilemma/problem I'm facing? thank you, in advance.

any problem at the other faucets?
what brand shower valve is it?
chances are it is in the cartridge/balancing spool and it needs cleaning or just replacing. (usually a pretty simple job)...

balancing spools can ONLY affect one side or the other, not both.