RV water heater error codes: two of the four makers show no code at all

Count the attempts — it is the code the light does not show

The two lamp-only makers can still be told apart, and told apart from a genuine gas fault, by how the appliance behaves in the ten seconds after you switch it on. Atwood documents a single trial for ignition: gas valve and electrodes energised together for six to eight seconds, and if the electrodes do not sense a flame in that window the board shuts the gas and goes to safety lockout. One attempt, then done.

Suburban documents the opposite: if the burner does not light, the system automatically attempts two more tries before lockout, and on a three-try system each ignition cycle begins with a 15-second purge before the spark cycle. So a Suburban audibly works at it for the better part of a minute; an Atwood gives up in under ten seconds.

Girard sits between the two: the board sparks for the full seven seconds, then closes the gas, purges for about 30 seconds, and makes one more attempt before it declares E1. That intermediate rhythm — spark, long silence, spark, then a number appears on the panel — is unmistakable once you know to listen for it.

Both lamp-only makers reset the same way, with different waits

Suburban: switch OFF, wait five seconds, switch ON. That restarts the ignition cycle. Its manual also makes a point that saves a lot of pointless diagnosis — the first start-up after the gas system has been opened may need several ignition cycles before the air is purged out of the lines. A brand new or freshly serviced installation that locks out twice and then runs is behaving normally.

Atwood: switch off and back on, but let the water cool first if the lockout came with heat. The relevant thresholds are all in its manual: the thermostat opens at roughly 140 °F, the ECO — the backup high-limit switch — opens above 180 °F, and the thermal cut-off is a one-shot fuse that blows at 190 °F. That last one matters. It is not a switch you reset; once it trips, it is replaced, and it trips because something blocked the burner or the flue rather than because the appliance was unlucky.

One shared electrical figure is worth checking before anything is replaced on either brand: the Atwood gas valve needs at least 10.5 VDC to open. A tired battery that still runs the lights can be too weak to open a gas valve, and the symptom is an ignition lockout that looks exactly like a gas fault.

The Girard code that is not a fault

Girard tankless units run a system timer. After 20 minutes of continuous operation the board shuts the burner down and shows "En" on the user control panel. Nothing is broken, nothing needs a part, and it clears with a soft reset: turn the hot water tap off and back on again.

It is worth naming because of when it happens — in the middle of a long shower, the exact moment when a water heater appearing to fail feels most like a real failure. A tankless unit that heats perfectly for twenty minutes and then stops is doing what it was designed to do.

Which brand is behind the panel in your coach

Atwood water heaters have been part of Dometic since 2014, so a unit badged or invoiced as Dometic may be an Atwood design with Atwood service literature — worth knowing when a parts list or a manual search comes up empty under one name.

Girard sits under Lippert, which is the same corporate parent as Furrion and Everchill. That has no effect on the codes, but it explains why the same troubleshooting documents turn up on Lippert’s support site rather than under the Girard name.

Truma is the European unit of the four. In a European caravan or motorhome it is usually a Combi, which heats the air and the water from one appliance — meaning a water fault and a heating fault come out of the same code list.

Common questions