My Burnham tankless oil boiler (V-14A-T) works at 80% efficiency. Unlike previous winters, the last two winters the shower hot water dropped off fairly quickly - esp. when the house heat kicked in. Last winter, even when I turned off the room thermostats before taking a shower, the water turned cold and stayed cold for a while. I don't think I need to replace the boiler due to its efficiency. Is it the coil that needs replacement??? Or should I be replacing the boiler altogether?
It could be just a bad mixxing valve element. Maybe you should look into adding an indirect fired water heater. They are kind of pricey but they work well and dont cost hardly anything to run
