Oct 24th 2026
Suburban Water Heater Won’t Light on Propane (DSI): Step-by-Step Troubleshooting
TROUBLESHOOTING · GAS
Suburban Water Heater Won’t Light on Propane (DSI): Step-by-Step Troubleshooting
Reset light on, clicking but no flame, or lights then goes out? Work through these checks in order, from free fixes to parts.
Check these first
- Is the propane on and the tank full? After a tank change, it can take several tries to purge air from the line.
- Is the ECO reset button tripped? Let the water cool below 110°F and press it.
- Reset lockout: switch OFF for 5 seconds, then ON.
- 12V at the switch must be 10.5–13.5 V. Gas pressure should be 11–14 in. water column.
Covers these models
Suburban tank water heaters with direct spark ignition (DSI). Pilot models (SW6P, SW10P) are covered in our 161156 pilot guide.
How the ignition sequence works
When the thermostat calls for heat, the reset light comes on and the board runs a purge of about 15 seconds. During the trial for ignition the light goes off, the gas valve opens and the electrode sparks. If no flame is sensed, it purges and tries again, up to 3 tries. After the third failure it locks out with the reset light on.
Step-by-step
STEP 1
Reset and try again
Switch OFF, wait 5 seconds, switch ON. Listen at the outside door for the click of the valve and the tick of the spark. Light a stove burner first to purge air after a tank change.
Does it light now?
Probably air in the line
Common after a tank swap or storage. If it keeps happening, keep going.
STEP 2
Check 12V and the ECO/thermostat
Measure 10.5–13.5 VDC at the switch. The 12V thermostat/hi-limit under the thermostat cover must be closed; press its reset button if it tripped (only after the water cools below 110°F). The thermostat is fixed at about 130°F and the ECO trips above 180°F.
No reset light at all?
Power or ECO problem
Check fuses, the switch, wiring and grounds. If 12V reaches a closed thermostat/ECO and there’s still no reset light, Suburban says replace the module board or switch/lamp assembly.
STEP 3
Look for spark
Watch through the burner opening during a try. No spark: check the electrode for a 1/8 in. gap, cracked porcelain or carbon, and check that it isn’t shorting to the door. Check the electrode wire.
Electrode cracked or worn?
STEP 4
Spark but no flame: check gas
Gas pressure should be 11–14 in. WC. Check the gas valve gets 12V during the trial for ignition, and that its coil reads 30–50 ohms. Inspect the brown valve wire. Clean debris from the burner tube and orifice (spiders love them).
Lights, then goes out after a few seconds?
Flame sense
The board isn’t seeing the flame. Clean the electrode, check its wire and ground, and make sure it sits in the flame. Then suspect the board.
Gas valve or board
With 12V at the valve and good pressure but no gas, replace the valve (161306 on later serials; 161109/525042 on older). With no 12V at the valve during the try, suspect the board.
Other symptoms Suburban lists
- Soot or backfiring at the vent: gas pressure, or a dirty burner, flue tube or vent.
- Delayed ignition: electrode position or gap, debris in the burner.
- Not hot enough: check the bypass valve and mixing valves (including an outside shower). See 7 things to check.
Parts for this repair
Suburban 520814 Ignition Control Board (SW series)View part →
Suburban 525005 Igniter Electrode (SW series)View part →
Suburban 525007 12VDC Thermostat / Hi-Limit (SW series)View part →
Suburban 161306 Gas Valve (newer SW models)View part →
Suburban 161109 / 525042 Gas Valve (older SW models)View part →
Suburban 525022 Thermostat / Hi-Limit CoverView part →Shop by category: Suburban parts, Suburban part finder.
FAQ
Why is my Suburban water heater reset light on?
It’s locked out after 3 failed tries to light. Switch off for 5 seconds and back on. If it locks out again, check gas, 12V, the ECO and the electrode.
What gas pressure does a Suburban water heater need?
11–14 inches of water column, per Suburban’s service manual.
What is the electrode gap on a Suburban water heater?
1/8 inch.
Where is the ECO reset on a Suburban?
On the thermostat/hi-limit assembly under the thermostat cover behind the outside door. Let the water cool below 110°F before pressing it.
Not sure which part fits? Contact us with your model and serial number from the data plate and we’ll confirm it before you order.
From Suburban (Airxcel) service and training, installation and operating manuals and the current Suburban RV parts manual.