Atwood Water Heater: “No spark / no ignition”
danger RV water heater fault codes
What it means
Dead unit with no spark at the electrode and no lockout-light activity, typically caused by a blown one-shot thermal cut-off (TCO) fuse on the power lead. The TCO permanently opens the circuit when the burner/flue area overheats (around 190°F) — usually from a blocked burner or flue — to prevent fire damage.
Most likely causes
- Blocked burner tube or flue (spider/mud-dauber nest) causing overheating that blew the TCO fuse most likely
- Blown thermal cut-off fuse (the clear plastic in-line fuse on the brown/power lead near the board) common
- Blown 12V fuse or no power to the board common
- Failed control board with no spark output less common
Safe checks you can do yourself
- Verify 12V power and check the unit's inline/12V fuse.
- Locate the thermal cut-off (clear plastic in-line device, looks like a resistor inside, on the brown power lead) and test for continuity with power off — no continuity means it has blown.
- Before replacing a blown TCO, find and clear the cause: inspect the burner tube and flue for insect nests/obstructions, because a fresh TCO will blow again if the blockage remains.
When to call a technician
If the TCO is blown, you cannot find an obvious blockage, or it blows again after replacement — have a qualified RV technician inspect the burner, flue, and gas valve. Repeated overheating indicates an unresolved combustion fault.
Applies to
G6A-7 · G6A-7E · G6A-8E · G6A series (DSI / electronic-ignition)
FAQ
What does Atwood Water Heater code "No spark / no ignition" mean?
Dead unit with no spark at the electrode and no lockout-light activity, typically caused by a blown one-shot thermal cut-off (TCO) fuse on the power lead. The TCO permanently opens the circuit when the burner/flue area overheats (around 190°F) — usually from a blocked burner or flue — to prevent fire damage.
What is the most common cause of No spark / no ignition on a Atwood Water Heater?
The most likely cause is blocked burner tube or flue (spider/mud-dauber nest) causing overheating that blew the tco fuse.
Related · Atwood water heater
On Atwood DSI (Direct Spark Ignition) water heaters there is… ECO open / tripped
The ECO is a backup high-limit temperature switch wired in s… Gas & spark, no flame proven
A diagnostic sub-condition of the DSI lock-out: both gas and… Gas present, no spark
A diagnostic sub-condition of the DSI lock-out from the offi… Spark present, no gas
A diagnostic sub-condition of the DSI lock-out from the offi… TCO (thermal cut-off) tripped
Current Atwood DSI water heaters have a one-shot thermal cut…
Sources
- Atwood G6A-7 / thermal cut-off no-spark troubleshooting — TCO fuse on power lead, no spark diagnosis (JustAnswer (RV))
- A Complete Guide to Atwood RV Water Heater Problems — Thermal cut-off blows from burner-chamber overheating (insect nests) (RV Upgrade Store)
- Atwood Water Heater Troubleshooting (Atwood service content) — TCO designed to permanently break circuit on overheat (All Things Foretravel)
Note: This is not an alphanumeric code — it presents as a dead/no-spark symptom. The trip temperature (~190°F) and fuse location vary slightly by model year. The TCO and the ECO are different devices and are easily confused (see next record).
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.