This is 100% broken heat exchanger its the coils inside of heater that heats the water this usually happines from really old age or because your climate temperature is below freezing and broke the coils, i see it all the time in winter season, best way to prevent this is to run your heater for fifteen minutes every month and make sure pool equipment runs all day everyday when its really cold out you can start running system normaly after your outside temp is warmer. its better to get a new heater when this happines heat exchanger is hard to install for most tech's pretty much have to take whole top part of heater off and is also expensive part
Answers & Comments
This is 100% broken heat exchanger its the coils inside of heater that heats the water this usually happines from really old age or because your climate temperature is below freezing and broke the coils, i see it all the time in winter season, best way to prevent this is to run your heater for fifteen minutes every month and make sure pool equipment runs all day everyday when its really cold out you can start running system normaly after your outside temp is warmer. its better to get a new heater when this happines heat exchanger is hard to install for most tech's pretty much have to take whole top part of heater off and is also expensive part