What actually fails on a tankless in Matthews
Tankless units tell you what is wrong if you read them. Nearly every call starts with an error code, and the code plus the gas supply narrows it down long before anyone needs to open anything.
The local variable is the water. Yours comes from Charlotte Water. Where that supply is soft, scale is a slower problem here than the national troubleshooting guides assume, which means a unit throwing a temperature fault in Matthews is more often a flow sensor, an igniter or a gas supply problem than the limescale everyone reaches for first.
- Ignition and flame failure codes: gas supply, igniter or flame rod before anything more expensive.
- Cold water sandwich: usually a behaviour of the system rather than a fault, and worth explaining before selling you a fix.
- Flow sensor faults: common, cheap, and frequently misdiagnosed as a failing exchanger.
- Heat exchanger: the one genuinely terminal failure, and often still under a long manufacturer warranty. We check the serial before quoting.
What Matthews itself changes
Where the heaters sit
Garage and crawlspace both common given the build era, with closet installs in the newer infill. Access is generally reasonable but the older subdivisions have tighter crawlspaces than the 2000s stock.
The housing in Matthews
Matthews is older than its reputation. The peak build decade is the 1980s at 23.1%, and 1980 to 1999 together account for 45.3% of the housing stock. That makes Matthews a third-cycle replacement market rather than a first-failure one: most of these homes are on their second or third water heater already, and the tanks going in now are replacing tanks that themselves replaced the original.