Oct 24th 2026
Suburban 520814 Ignition Control Board: What It Fits and How to Tell If It’s Bad
PARTS GUIDE · CONTROL BOARD
Suburban 520814 Ignition Control Board: What It Fits and How to Tell If It’s Bad
The 520814 is the ignition module on most Suburban SW DSI water heaters. Before you buy one, rule out the cheaper causes that look exactly like a bad board.
The short version
- 520814 fits Suburban SW-6/10/12/16 D, DE, DEL, DEM, DEC and DELC (and SW4D) water heaters.
- It does not fit the SAW6 Direct-Fit (that’s 521166) or the SW16V/VE (520993).
- 090487 is the board’s cover, not a board. And 521099 is a furnace board.
- Check 12V (10.5–13.5 V), the thermostat/ECO, the electrode and gas pressure before blaming the board.
Which board fits your heater
| Part | What it is | Fits |
|---|---|---|
| 520814 | Ignition control module | SW4D, SW-6/10/12/16 D / DE / DEL / DEM / DEC / DELC |
| 521166 | Ignition control module | SAW6D, SAW6DE, SAW6DEL (Direct-Fit) |
| 520993 | Ignition control module | SW16V / SW16VE (120V DSI) |
| 090487 | Module board cover (not a board) | SW4D/6D/6DE, SW10–16D/DE |
| 521135 | Module board (tankless) | IW60 Nautilus |
From Suburban’s current RV parts manual and service manual. Check the model on your data plate before ordering.
What the board does
When the thermostat calls for heat, the board runs a purge, then sends 12V to the gas valve and high voltage to the electrode. When the flame heats the electrode it produces a tiny flame-sense current; once the board sees it, sparking stops and the valve stays open. Suburban’s boards make three tries, then lock out with the reset light on.
Step-by-step: is it the board?
STEP 1
Check 12V at the switch
Suburban wants 10.5–13.5 VDC at the on/off switch. Low battery or a bad ground causes no-ignition and lockouts that look like a dead board.
STEP 2
Check the thermostat and ECO
The 12V thermostat/hi-limit must be closed for the board to get power. Press the ECO reset button (let water cool below 110°F first).
Reset light comes on when you switch it on?
Check wiring, then board
With good voltage and a closed thermostat/ECO, check the wiring to the board and reset light and the ground connections. If those are good, Suburban says replace the module board or the switch/lamp assembly.
STEP 3
Check for spark
Watch or listen at the burner during the trial for ignition. No spark: check the electrode (1/8 in. gap, cracked porcelain, carbon) and its wire first.
STEP 4
Check the gas valve gets 12V
Measure at the valve during the trial for ignition; the coil should read 30–50 ohms off the circuit. Check gas pressure: 11–14 in. water column.
Good voltage, good electrode, good gas, still no spark or no valve voltage?
Replace the board
Match the board to your model (520814 for most SW DSI units).
Flame sense problem
If the burner lights and goes out when sparking stops, the board isn’t seeing flame. Check the electrode, its wire and ground before the board.
Replacing it
- Power off: turn off the switch and disconnect 12V.
- Photo the wiring: take a picture of every connection before you unplug anything. Suburban’s wiring uses red, brown, green, yellow, blue and black wires; the brown wire feeds the gas valve.
- Protect it: Suburban says the board and its wiring must be protected, and use insulated terminals and 18 GA 105°C wire if any needs replacing.
- Reinstall the cover (090487 on most SW D/DE units).
Parts for this repair
Suburban 520814 Ignition Control Board (SW series)View part →
Suburban 090487 Module Board CoverView part →
Suburban 521166 Control Board (SAW6D / SAW6DE / SAW6DEL)View part →
Suburban 525005 Igniter Electrode (SW series)View part →
Suburban 525007 12VDC Thermostat / Hi-Limit (SW series)View part →Shop by category: Suburban parts, Suburban part finder.
FAQ
What does the Suburban 520814 fit?
Suburban SW-series DSI water heaters: SW4D and SW-6/10/12/16 D, DE, DEL, DEM, DEC and DELC.
Is 090487 a board?
No. In Suburban’s parts manual, 090487 is the cover for the 520814 module board.
Does the 520814 fit the SAW6?
No. The SAW6D/DE/DEL Direct-Fit uses 521166.
How do I know if my Suburban water heater board is bad?
With 10.5–13.5 V at the switch, a closed thermostat/ECO, a good electrode and 11–14 in. WC gas, no spark or no voltage at the gas valve points to the board.
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.