Elements & Thermostats

Diagnosing and matching water heater controls

A cold tank narrows down fast once you know which system failed. If the electric side is dead but gas still heats, the element or thermostat is the suspect. If gas won't light, look at the ignitor board, thermocouple, or gas valve. Pin down the symptom first, then match the part to your heater's exact brand and model, since Suburban, Atwood, Dometic, and Girard parts don't interchange.

• Heating elements. The 120-volt element does the electric heating. Wattage matters — a hybrid kit like Camco's 625-watt element lets a 10-gallon gas heater also run on shore power. Match voltage and wattage, and always kill the breaker before you touch it.
• Thermostats and ECO. The thermostat sets water temperature; the ECO (high-limit cutoff) trips if it overheats. A tank that heats then goes cold, or won't heat at all on a good element, often points here.
• Thermocouples and ignitor boards. On gas heaters, the thermocouple proves the pilot flame and the ignitor board sparks and controls the burner. Dinosaur Electronics' UIB boards are near-universal replacements for failed Atwood boards and end a lot of no-light headaches.
• T&P relief valve. The temperature-and-pressure valve is a safety device — it weeps if the tank over-pressures. Replace a dripping or crusted valve with the correct 3/4-inch rating; never plug or cap it.
• Tankless flow sensors. On-demand heaters like the Girard GSWH-2 use a flow sensor to confirm water is moving before they fire. A tankless unit that won't light on flow is often a fouled or failed sensor.

Chasing a no-heat problem often ends at one cheap part rather than a new heater. If the tank itself is shot, price complete water heater units; if the water's rusty or smells, start with the anode rod. And before you blame an electric element, confirm the circuit at the breaker.