Takagi Error Code 207: Bypass Valve Error

Severity
Warning
Type
digital display
Estimated repair cost: $100 — $350 (parts + labor)
Warning: Your Takagi tankless water heater has detected a problem with the bypass valve. This will likely prevent hot water from being produced until the issue is resolved.

How to Fix Takagi Code 207

  1. Step 1: Turn the unit off and back on again. This may reset the system and clear a temporary error.
  2. Step 2: Check the unit's display for any other error codes. Multiple codes can help narrow down the problem.
  3. Step 3: If the error persists after restarting, contact a qualified HVAC technician to diagnose and repair the issue.

How to Reset Takagi Code 207

  1. Turn off the unit using the power button on the front panel.
  2. Turn off the gas supply valve.
  3. Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
  4. Restore power at the breaker, then open the gas valve.
  5. Turn the unit back on. If the error returns, the underlying issue needs repair.

Resetting clears the code from the display but does not fix the underlying fault. If the code returns after reset, proceed to the diagnostic steps above.

What Does Takagi Error Code 207 Mean?

The Takagi 207 error code indicates a problem with the bypass valve. This valve is designed to divert water flow within the unit during periods of low demand or when the unit is starting up. It helps to maintain a stable temperature and prevent cold water from entering your hot water lines unexpectedly. When the system detects a malfunction in the bypass valve circuit, it shuts down to prevent potential damage or inconsistent water temperatures. This error can stem from electrical issues with the valve itself, problems with the control board that operates the valve, or even mechanical obstructions preventing the valve from moving freely. Because the unit relies on this valve for proper operation, a 207 error will typically result in a complete shutdown of hot water production.

Common Causes

  • Defective bypass valve motor or solenoid.
  • Wiring issues between the bypass valve and the main control board (loose connections, damaged wires).
  • Failed main control board not sending the correct signal to the bypass valve.
  • Mechanical obstruction preventing the bypass valve from moving freely (debris, scale buildup).

Diagnostic Steps

If... Check Expected
Unit displays error code 207 Measure the voltage at the bypass valve connector on the main control board when the unit attempts to activate the valve. Expect to see 24V DC when the valve is supposed to open or close.
Voltage is present at the connector Measure the resistance across the bypass valve motor/solenoid terminals. Compare the measured resistance to the manufacturer's specifications (typically found in the service manual). An open circuit or short circuit indicates a faulty valve.
Bypass valve resistance is within spec Inspect the wiring harness between the bypass valve and the main control board for any signs of damage or loose connections. Wiring and connections should be intact and secure.
Wiring is OK, but valve doesn't actuate Manually check the bypass valve for free movement. It should move smoothly without resistance. Valve moves freely.

Applicable Takagi Models

Replacement Parts

Part OEM Number Est. Cost Where to Buy
Bypass Valve Assembly
Main Control Board
Wiring Harness

Related Codes on Same Models

Other codes that affect the same Takagi model families as 207.

Code Description Severity
101 Combustion Abnormality Critical
111 Ignition Failure Critical
121 Flame Failure Critical
200 Overheating Warning
291 Flow Rate Issue Warning
312 Outlet Temp Sensor Warning
321 Inlet Temp Sensor Warning
391 Exhaust Temp Sensor Warning
510 Gas Solenoid Valve Critical
610 Fan Motor Fault Warning