Mobile RV LP Gas Solenoid Valve Replacement Across Florida
The LP solenoid valve is the automatic shutoff that closes the gas supply when the coach is not in use or the LP detector trips. When it fails open, everything runs until the tank empties. When it fails closed, nothing runs at all. Replacement is a one-hour job.
The LP solenoid in an RV is a normally-closed valve, meaning it is spring-held shut when unpowered. It opens only when 12 volts DC is applied to its coil. This design is deliberate: if the coach loses power, the gas automatically stops. When the solenoid coil's resistance drifts out of spec from corrosion or heat cycling, it may draw insufficient current to open fully, producing partial gas flow rather than a clean open or shut - a failure mode that mimics low regulator pressure and is commonly misdiagnosed.
The Role of the LP Solenoid in the Safety Circuit
Every modern RV with an LP system includes an LP gas detector mounted low in the coach interior, typically near the floor in the living area. This detector is wired in series with the LP solenoid. When the detector senses propane concentration above its threshold, it cuts 12-volt power to the solenoid, which closes and stops gas flow throughout the coach. The solenoid is the enforcement mechanism for the detector - without a functioning solenoid, the detector is an alarm with no ability to actually stop the gas.
The same 12-volt circuit that powers the solenoid is typically also controlled by the coach ignition or house power switch. When you shut off the coach's house systems, the solenoid closes. This is why propane appliances - the refrigerator running on LP, the water heater, the furnace - all stop when the house power is switched off entirely. It is not a fault, it is designed operation.
Florida coaches in full-time use run the solenoid open continuously during periods of use and cycle it many times per day when the coach is being managed between use periods. Over time, the coil can develop increased resistance from corrosion at the wire connection points, or the valve seat can accumulate debris that prevents full closure. A solenoid that does not close completely is as much of a safety concern as one that does not open.
Diagnosing Solenoid vs Regulator vs Empty Tank
When all LP appliances stop working simultaneously, the diagnosis sequence matters. The first check is always tank level - not the gauge, which is notoriously unreliable on many coaches, but tank weight or direct observation of frost line during cool-weather operation. If gas is present in the tank, the next step is testing voltage at the solenoid terminals. A voltmeter placed across the solenoid coil should read 12 volts DC when the house power is active and the LP system is enabled.
If voltage is present at the coil but the solenoid is not opening, the coil resistance is the issue. We measure coil resistance with the power off - a typical LP solenoid coil reads 8 to 15 ohms. A coil reading significantly outside this range has developed a fault and the solenoid requires replacement. If voltage is present and coil resistance is within spec but gas still does not flow, the valve body itself is stuck - mechanical failure of the valve seat or spring. This also requires replacement.
If voltage is not present at the solenoid terminals, the issue is upstream in the control circuit. This requires tracing back through the LP detector, the power switch, and the wiring harness. We use a circuit schematic specific to the coach to identify the break rather than probing randomly. Wiring faults - corroded terminals, chafed insulation in the LP compartment where heat and moisture are highest - are common in Florida coaches regardless of age.
The Replacement Procedure
LP solenoid replacement begins with both tank valves closed and the 12-volt circuit de-energized. The solenoid body is typically threaded into the LP inlet line using NPT fittings. We disconnect the electrical leads, remove the old solenoid, inspect the threads and fitting condition on the coach side, and install the new solenoid with fresh LP-rated thread sealant. The electrical connections are made with weatherproof crimp connectors rather than tape, because the LP compartment environment degrades standard electrical tape within one to two Florida summers.
After installation, the tank valves are opened and the full LP system is pressure-tested at 10 PSI before any appliance is relighted. The solenoid function is then verified by applying and removing 12 volts while monitoring pressure downstream - the valve should open and close cleanly with each cycle. Finally, all appliances are relighted and confirmed operational.
In coaches where the solenoid wiring has corroded or broken, the wiring repair happens before solenoid replacement. Replacing only the solenoid while leaving corroded wiring in place guarantees a repeat service call within a season. We run new wire from the solenoid to the nearest solid connection point in the harness when the existing wiring has visible damage rather than splicing into deteriorated insulation.
When the Full LP Safety Circuit Should Be Serviced Together
The LP solenoid, the LP detector, and the regulator form a system. In Florida, where all three face heat, humidity, and UV exposure, it is common for coaches to present with degraded function in two of the three at the same time. A coach with a failing solenoid that also has a five-year-old detector and a ten-year-old regulator will benefit from addressing all three in a single visit rather than reactive replacements one at a time over successive years.
We offer a full LP safety circuit service that includes solenoid replacement, detector function test with replacement if indicated, and regulator pressure test with replacement if out of spec. This combined service costs less than three separate service calls and produces a fully certified LP system. For Florida coaches approaching any of these service intervals, the combined service is the better economic decision and the better safety outcome.
Coaches that have been in extended summer storage in Florida should have the LP safety circuit verified before re-use each fall. The solenoid coil and detector sensor both degrade in the sustained heat of a closed storage unit or covered storage facility, and the combination of a marginally-functioning detector and a slow-to-close solenoid is not an acceptable operating condition for a coach with occupants.
Pricing Reference
| Service | Notes | Range |
|---|---|---|
| Service call + solenoid diagnosis | Voltage test at solenoid coil; manual override test; LP system pressure check | $299 - $399 |
| 12V solenoid valve replacement | Standard normally-closed solenoid; includes LP pressure retest | $110 - $280 |
| Solenoid wiring repair | If coil is good but wiring is corroded or broken | $75 - $185 |
| LP detector + solenoid circuit test | Verifies detector properly triggers solenoid and solenoid actually closes | $95 - $195 |
| Full LP safety circuit service (detector + solenoid + regulator) | Complete safety system service; single visit | $280 - $580 |
Pricing shown is a national average range for reference. Actual cost depends on coach type, access, parts required, and location within Florida. Triton RV Repair provides a firm quote before any work begins.
Call (888) 702-6880 or schedule online for a site-specific estimate.
Frequently Asked Questions
What does the LP solenoid valve actually do?
Why did all my propane appliances stop working at the same time?
How do I know if the solenoid is stuck closed versus the tank is empty?
Is it safe to bypass the LP solenoid in an emergency?
What triggers the LP solenoid to close automatically?
Where is the LP solenoid located in most RVs?
Sources
- Marshall Excelsior LP solenoid documentation - 12V solenoid valve specifications, coil resistance values, and trigger circuit wiring for RV LP systems.