Complete repair guide for the Entegra Aspire – Furnace Igniter & Control Board Replacement. Follow these steps to diagnose and fix the issue yourself.
Parts & Tools You’ll Need
- Suburban RP-35Q 35,000 BTU/h RV Replacement Core for Suburban Furnace Series SF-35, SF-35Q, SF-42, SF-42Q, and SF-Q (2609A) — Suburban/Atwood RV furnace (replacement unit)
- Fit For Suburban RV Furnace Parts 232286,Single Probe Gas Furnace Igniters Electrode with Wire Assembly, Camper Furnace For Suburban 232286 Above 934701426 SF-20, SF-25, SF-30, SF-35 (SF Series) — Furnace igniter electrode
- DTAIR 33082 Sail Switch Replacement for Select Dometic Atwood RV Furnace(Pack of 2) — Furnace sail switch
- 520814 Rv Water Heater Module Board Ignition Control Circuit Board Compatible with Suburban Furnace SW4D, SW6D, SW6DE, SW12D, SW6DEM RV Water Heaters,Replace 520814 520820 520871 33550L (With lid) — Furnace circuit board / control board
- DTAIR 33082 Sail Switch Replacement for Select Dometic Atwood RV Furnace(Pack of 2) — Furnace high-limit switch
- Suburban 232684 RV Furnace 12v SF-Series DC Blower Motor, SF-35, SF-35F, SVF-35, SF-42, SF-42F OEM Caliber — Furnace blower motor (12V DC)
- RV Carbon Monoxide & Propane Gas Alarm, Briidea Dual LP/CO Detector with Separate LED Indicator Light, 100dB Loud Alarm, 12 VDC, Black — Propane/CO combo detector alarm
- FKM Pro Digital Multimeter Tester TRMS 6000 Counts,Smart Rechargeable Voltmeter 5″Color LCD,Auto-Ranging Automotive Multimeters,for AC/DC Current/Voltage,NCV,Ohm,Capacitance,Resistance,Continuity,Temp — Digital multimeter
Step 1: Diagnose the Ignition and Control Issues
Start by visually inspecting the furnace igniter electrode for signs of damage, corrosion, or buildup that would prevent proper spark generation. Use your digital multimeter set to the ohms setting to test the igniter electrode—you should see a resistance reading between 4 and 14 ohms; any reading outside this range indicates a failed electrode. Next, check the circuit board for visible burn marks, corrosion, or loose connections, and verify that your propane/CO combo detector isn’t triggering a safety lockout that would prevent the furnace from attempting ignition.
Step 2: Safely Disconnect Power and Propane
Turn off the 12V DC power to the furnace at your RV’s main breaker panel, and wait at least 5 minutes for any residual power to dissipate from the control board capacitors. Locate the propane isolation valve near your furnace and turn it fully counterclockwise to cut off the gas supply, then attempt to ignite the furnace manually to confirm the line is depressurized. Double-check that your Propane/CO combo detector is functioning and will alert you if any gas escapes during the replacement work.
Step 3: Remove the Furnace Access Panel and Components
Open the furnace access panel (typically held with 3-4 Phillips head screws) and carefully photograph or diagram the wire connections to the control board, igniter electrode, sail switch, and high-limit switch before disconnecting anything. Disconnect the igniter electrode by gently pulling the spade connector away from the board, then locate and disconnect the sail switch (a small lever-activated safety sensor) and the high-limit switch, which are typically mounted near the heat exchanger. Remove the old control board by unbolting it from its mounting bracket—note that some boards are held with two M4 bolts and others use push-pin connectors.
Step 4: Install the New Furnace Control Board
Position the new circuit board onto the mounting bracket and secure it with the appropriate bolts or connectors, ensuring the board sits flat and level without any twisting or stress on the connection points. Reconnect the sail switch and high-limit switch spade connectors first, pressing firmly until you hear a slight click, then reconnect the igniter electrode lead to the designated terminal on the new board (typically labeled ‘Igniter’ or ‘Spark’). Verify that all connectors are fully seated by gently tugging on each wire—there should be no movement or gaps.
Step 5: Replace the Furnace Igniter Electrode Assembly
If your multimeter confirmed the electrode is failed, locate the ceramic electrode holder (usually a small white or beige component mounted inside the burner chamber) and unbolt or unclip it from the furnace frame. Carefully insert the new furnace igniter electrode into the holder, positioning the tip approximately 1/4 inch (6mm) from the main burner orifice, and secure the assembly with the original hardware—do not overtighten as ceramic can crack. Connect the new electrode’s spade connector to the igniter terminal on your fresh control board.
Step 6: Reassemble the Furnace and Restore Power
Reconnect the 12V DC power supply by switching your RV’s main breaker back to the ON position, then turn the propane isolation valve clockwise to restore gas supply to the furnace. Reinstall the furnace access panel and tighten all screws evenly, then allow 2-3 minutes for the system to initialize before attempting ignition. Monitor your Propane/CO combo detector to ensure no alarms sound during this initialization period.
Step 7: Test Ignition, Heat Output, and Safety Systems
Set your RV thermostat to heat mode and raise the temperature setting 5 degrees above the current cabin temperature to trigger the furnace ignition cycle. Listen for the characteristic ignition spark (a soft clicking sound) followed by the blower motor engaging within 10-15 seconds—the furnace should begin producing warm air within 30 seconds of burner ignition. Run the furnace continuously for 10 minutes and verify that the sail switch safety shutdown doesn’t trigger incorrectly, then cycle the thermostat on and off three times to confirm reliable repeated ignition with no propane smell or CO detector warnings.