AIRSTREAM CLASSIC 33FB - LP Gas Detector Replacement

AIRSTREAM CLASSIC 33FB – LP Gas Detector Replacement

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Complete repair guide for the AIRSTREAM CLASSIC 33FB – LP Gas Detector Replacement.

Parts & Tools You’ll Need

Step 1: Diagnose Current Detector Status

Locate your existing LP gas detector—typically mounted on the interior wall near the kitchen or sleeping area in your 33FB. Use the Non-Contact Voltage Tester to confirm power is reaching the unit, then check the detector’s test button and indicator light to determine if it’s functioning or requires replacement due to age (detectors have a 7-10 year lifespan) or malfunction.

Step 2: Disconnect Power and Remove Old Unit

Turn off the 12V DC power at your Airstream’s main battery disconnect or breaker panel serving the detector circuit. Carefully disconnect the wiring harness pigtail connector from the back of the old detector, then unscrew the flush-mount housing from the wall using a Phillips head screwdriver—typically two to three fasteners hold it in place.

Step 3: Inspect and Prepare Wall Opening

Examine the wall cavity and existing wiring for any damage or corrosion, particularly around moisture-prone areas. Use a dry cloth to clean out any dust or debris from inside the wall opening, ensuring a clean surface for the new detector’s gasket seal to prevent propane vapor leakage.

Step 4: Install New Detector Housing

Position the Safe-T-Alert 35-742 or MTI Industries 35-742-P-WT flush-mount housing into the wall opening, aligning the screw holes. Secure it with the provided fasteners, tightening to approximately 8-12 inch-pounds—snug but not over-tightened, as excessive force can crack the plastic housing or damage the internal sensor.

Step 5: Connect 12V DC Wiring Harness

Strip approximately ¼ inch of insulation from the existing detector circuit wires if needed, then attach the 12V DC Wiring Harness Pigtail Connector to match the positive (red) and negative (black) terminals on the new detector. Use the Wire Nuts from your kit to secure connections, then wrap each joint with Electrical Tape to prevent corrosion and moisture intrusion in your RV’s humid environment.

Step 6: Restore Power and Initialize Detector

Reconnect power at the main battery disconnect, then observe the new detector’s LED indicator light—it should illuminate within 10 seconds and produce a brief beep to confirm 12V DC power is flowing. If the light and sound don’t activate, immediately disconnect power and recheck your wire connections for correct polarity.

Step 7: Test Detector Response and Function

Press and hold the detector’s test button for 3-5 seconds—you should hear a loud alarm and see the warning indicator activate, confirming the alarm circuit functions properly. Spray a small amount of Propane Leak Detector Spray near (but not directly into) the detector’s sensor vents to verify it responds to propane presence; if the alarm doesn’t sound within 15 seconds of exposure, disconnect and replace the unit immediately.