Takagi Non-Condensing Code 55
Abnormal solenoid gas valve (T-K4, T-KJr2). The solenoid gas valve is not behaving. This one has no three-digit form: Takagi marks the 7-segment column N/A, so it appears as 55 on a T-K4 or T-KJr2 remote, or six flashes of the red LED. Solenoids are the electrically operated gates that admit gas and, more importantly, close to stop it.
Call a proThe verdict
Call a licensed plumber
A gas valve fault, professional only. Because solenoids are what shut the gas off, this is not a code to run past while waiting for an appointment.
Typical cost: $250–$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
Before anything else: if you smell gas, stop here, leave, and call your gas utility.
- Turn the heater off and close the manual gas valve below it.
- If you smell gas, leave the building and call your gas utility from outside.
- Book a licensed professional.
Frequently asked questions
Why does this code have no three-digit version?
Takagi's table marks the 7-segment LED column N/A for it. A T-D2 reports gas valve problems as 510; the T-K4 and T-KJr2 split them into 51 and 55.
Don't confuse this with
2 other Takagi Non-Condensing codes point at a valve too. They are different components in different places, and ordering a part against the wrong one is the most common way this fault gets expensive: