Replace the main heat exchanger

What is going on

Drain the boiler and disconnect the heating piping, relief valve pipe, air purger and return pipe before removing the heat exchanger.

Check in this order

1. Drain the boiler and remove the combustion assembly.
2. Remove the exhaust vent adapter on top of the boiler.
3. Remove the two screws holding the CH relief valve pipe assembly to the top of the boiler.
4. Remove the three clips on the automatic air purger, then remove the CH relief valve pipe.
5. Disconnect the bottom of the heating supply pipe from the hydraulic group and from the air purger.
6. Remove the automatic air purger from the heat exchanger.
7. Disconnect the return pipe from the top of the pump, remove its clip and remove it from the boiler.
8. Remove the condensate pipe as needed.
9. Remove the six fixing screws from the heat exchanger. Remove the lateral panel if the left screws are hard to reach.
10. Install the new heat exchanger, replace all sealing rings, and check for gas leaks.

More boiler guides

• Access the low voltage wiring connections
• Blocking errors versus lockout errors
• Blower not running
• Blower runs at high speed with burner off
• Boiler bangs or hisses; Lockout 81 delta T
• Burner not running on a call for heat