Takagi Non-Condensing Code 701
Computer board fault. The computer board itself. Worth noting the difference from the condensing range, where the same number covers the proportional valve **or** the computer board; here Takagi names the board alone. Shown as 70 on a T-K4 or T-KJr2 remote, or one flash of the red LED.
Also displayed as: 70
Call a proThe verdict
Call a licensed plumber
The most expensive electronic part in the unit. Check the warranty position before booking, and on an older heater get the repair-versus-replace comparison in writing.
Typical cost: $400–$1,100
US estimate for parts and labor. Prices vary by region and by who does the work — see how we estimate costs.
What the manual says
The meaning above is transcribed from the manufacturer's diagnostic documentation for the Non-Condensing — not averaged across the brand.
Source: Takagi Non-Condensing Models On-Demand Water Heater Troubleshooting Guide (p. 12), read Aug 2026 — the manufacturer's own documentation for this exact series.
What you can safely check
- Turn the heater off and leave it off.
- Check whether the unit is still within its parts warranty.
- Book a licensed professional.
Frequently asked questions
The condensing version of 701 mentions a proportional valve too.
It does, and that is a real difference between the two tables. On a condensing Takagi, 701 means the proportional valve or the computer board; here it names the board alone, which narrows the diagnosis.
Code 701 on other Takagi series
The same code number can mean something different on another series — make sure you're reading the page for your exact unit: