Rheem tankless control board
Use for price checking after diagnostics confirm the PCB is failed. Match the board number exactly.
$120-$450
Check price
A Rheem tankless water heater main control board, or PCB, should be the last part you buy, not the first. A bad sensor, loose connector, failed fan, weak flame signal, blown fuse, or poor ground can look like a board failure from the display.
Use this page to price the right repair path, then match the exact board number to the water heater label and service manual.
Before Replacing the Board
| Check | Why it matters |
|---|---|
| Incoming power | Low or missing power can freeze logic |
| Ground and fuses | Bad ground creates erratic board faults |
| Sensor connectors | Open thermistors can mimic PCB failure |
| Fan operation | Combustion-air faults may stop startup |
| Flame signal | Dirty flame rods create lockouts |
| Board number | Wrong PCB revision may not configure |
Safe Diagnostic Order
- Turn power off and remove the front cover.
- Photograph every connector before touching the board.
- Inspect for water staining, corrosion, swollen capacitors, burned traces, or rodent damage.
- Reseat low-voltage connectors one at a time.
- Check the displayed error code against the Rheem service chart for that model.
- Test the sensor or fan named by the code before condemning the board.
- If the board is confirmed failed, match the printed board number and model number before ordering.
When to Call Service
Call a licensed plumber or HVAC technician if the fault involves gas combustion, fan speed, flame proving, live voltage testing, or a board replacement. After control replacement, the unit may need setup checks before returning to service.