Just looking for confirmation on what I am assuming is the issue. Friends heater fires fine. After 5 minutes high limit 2 fault.
Quick inspection and I find the spring for the internal bypass valve is a mess. I am assuming that because the valve is basically open there is not enough water going into heat exchanger which is causing the overheat situation? Replace spring and all should be good again?
On a side note this is why tablet feeders should not be plumbed directly off the outlet for the heater.

Quick inspection and I find the spring for the internal bypass valve is a mess. I am assuming that because the valve is basically open there is not enough water going into heat exchanger which is causing the overheat situation? Replace spring and all should be good again?
On a side note this is why tablet feeders should not be plumbed directly off the outlet for the heater.
