Water heater is overheating

Overheating is most often caused by air in the system or a restriction in the coolant flow.

Here’s how to troubleshoot:

1. Purge the system: Remove any air from the coolant system and check for restrictions.

2. Check the air heat exchanger: Some exchangers have rubber inserts on the coolant ports to protect them during shipping. Make sure these are removed.

3. Inspect the water pump: Blockages in the pump can cause overheating. If possible, bench test the fuel pump to ensure liquid flows freely. If it doesn’t, check for and clear any blockages in the pump itself.