i hope someone can help me with this and im going to try and explain this best as possible.
about 10 years ago we had a new furnace installed hot water type. i remember the installers telling me with this furnace we wont need our hot water heaters as the furnace will feed the entire house. over the last say 4-5 years i noticed that in my shower which is on the 2nd floor of the house the hot water started to get wacky. i wouldnt have enough hot water for the house for an extended period of time. recently over last two years. i noticed in the winter time when furnace was most active we would loose hot water pressure only on the 2nd floor shower. the 1st floor shower is perfect. if i turn on my hot water heater the pressure would get better but then the water would be warm not hot. but the problem is my hot water heater which starts up fine runs for a few minutes then shuts off does not come back on by itself i have to manually turn it on it will fire up again but then after a few minutes shuts down and doesnt restart.
i have been trying to figure out what is the problem is it the installers of my furnace was wrong and the hot water heater was still feeding the 2nd floor and now has some sort of problem that is causing all my problems.
please understand i know exactly zero about plumbing and not even sure i can explain this properly. this is my mothers house that we share and we cannot afford to bring in a plumber for help. if there is any other info i can provide to even begin to help please let me know