Takagi parts are sold through the AO Smith distributor channel (Ferguson, Hajoca, Winsupply) plus authorized Takagi/AO Smith installers. Amazon stocks high-volume parts. Internal parts (heat exchanger, gas valve, PCB) are dealer-only.
The Takagi parts catalog
- Heat exchanger — primary failure after 10-15 years on scaled units
- Flame rod — most-replaced. Behind 60% of Code 112 faults
- Igniter — Code 111 cause on older units
- Gas valve — dealer-only
- Control board (PCB) — model-specific
- Flow sensor — common failure on older T-H1/T-K units
Where to buy
- Amazon — flame rods, igniters, isolation valves, flow sensors
- Plumbing wholesaler — Ferguson, Hajoca, Winsupply (AO Smith network)
- Takagi authorized installer — full catalog
- Takagi via AO Smith — warranty replacement only
Bottom line
Flame rod, igniter, flow sensor are routine DIY with model-specific part numbers. Heat exchanger, gas valve, PCB through Takagi-trained installer.