The Propane Out-of-Gas Relight SOP

Purpose

When a propane tank runs dry, every pilot in the house goes out, the piping loses pressure, and whatever caused the tank to run low may still be there. This procedure guarantees that gas is not restored to the appliances until the system has been shown to hold pressure, that every appliance is relit and proven, and that a record exists showing who checked what. Without it, an appliance with an open standing-pilot valve can release unburned gas the moment the tank is refilled.

Scope

Covers: residential propane systems after a run-out or any interruption of service, from arrival through the last appliance relit and the record closed. Performed only by a technician who is qualified under your state's rules to leak-check and work on propane piping and appliances.

Does not cover:

• An active leak or a gas odor on arrival. That is a leak response first: everyone out, no switches, tank valve closed only if reachable without passing through gas, 911 and the supplier called from a safe distance. See related: Propane Homes: What Every Trade Should Know.
• Tank, service valve, or first-stage regulator replacement, which belongs to the propane supplier.
• Natural gas service interruptions, which follow the utility's restoration procedure.

Roles and responsibilities

Procedure

1. Confirm the run-out and screen for gas. Before entering, read the tank float gauge and walk the house with a combustible gas detector, holding it near the floor in every room with a gas appliance, since propane sinks. Ask the customer whether anyone has already opened the tank valve or relit a pilot since the delivery. Accept when the gauge reads at or near zero (a few percent at most) and the detector reads zero at floor level in every appliance room. Wrong looks like any detector reading or rotten-egg odor: stop this SOP, leave with the occupants, and run the leak response. If the gauge reads well above empty, this is not a run-out; diagnose the supply problem instead. Hazard: while screening, operate no switches and plug nothing in until the detector has read zero in that space.

2. Close every appliance valve and inventory the system. Turn each appliance control to off and close its appliance shutoff valve: furnace or boiler, water heater, range, dryer, fireplace or log set, space heaters, pool heater, generator, grill, and any outdoor branch. Write each one down. Then trace the piping from the second-stage regulator for tees feeding something nobody listed. Accept when the number of closed valves equals the number of appliances found by tracing, and every one is written on the record. Wrong looks like a valve that will not close, a branch with no appliance and no cap, or a pipe leaving the house to something unknown: cap or plug the open outlet before continuing, and if that cannot be done today, leave the system off and red-tag it. Hazard: an uncapped outlet is a full-flow leak when the tank valve opens; never proceed with one open.

3. Receive the fill with the service valve closed. The supplier fills the tank (or confirms it already holds liquid). The tank service valve stays closed after the fill until step 5. Agree with the driver on who opens it and when; some suppliers' procedures require their driver to witness or perform the leak check. Accept when the gauge reads at the fill level the supplier states and the service valve is confirmed closed by hand, clockwise. Wrong looks like a driver opening the valve to "get you going" before the leak check: close it and explain the code requirement. If the supplier will not fill, stop and reschedule. Hazard: stand clear of the fill connection and the tank's relief valve during filling, with no smoking or running engines within the supplier's stated distance.

4. Inspect the visible system before pressurizing it. Look at the first-stage and second-stage regulators, their vents, the line between them, exposed copper or flexible tubing, and each appliance connector. Accept when each regulator vent points down or is protected, is free of ice, insects and debris, regulators show no heavy corrosion, and every flexible appliance connector is a currently listed type with no kinks, cracks, or uncoated old brass. Wrong looks like a blocked vent, a corroded or water-filled regulator, or an old uncoated brass connector: a supplier-owned regulator goes to the supplier and the system stays off; a connector you are qualified to replace goes on the replacement list for after the leak check, or now if you carry one. Hazard: do not twist or flex an old brass connector to look at it, which can crack it.

5. Leak-check the system as the code and your supplier require. NFPA 54, in the edition your jurisdiction adopted, requires the piping to be checked for leakage immediately after gas is restored following an interruption of service, and NFPA 58, as your state adopted it, carries a matching leak-check requirement for the propane system itself. Use the method your supplier and your state accept, commonly a lock-up or pressure-drop test: connect a manometer to a low-pressure test point, open the service valve to pressurize the system, close it, and watch the gauge for the hold time your procedure sets. Accept when the reading holds with no drop for the full hold time. Wrong looks like any drop: close the service valve, find the leak with leak-detector solution or an electronic detector at every joint, connector, and valve, repair it if you are qualified, and repeat this step from the start. If you cannot find or fix it today, leave the service valve closed, red-tag the system, and tell the supplier and customer in person. Hazard: never hunt a leak with a flame; keep ignition sources out of the space.

6. Purge air from each branch, one appliance at a time. Open one appliance shutoff and bleed air from that branch per NFPA 54's purging requirements and the appliance instructions, through the burner or a purge point vented outdoors or to a well-ventilated space with no ignition source. Accept when the purge point shows steady gas (odor at the burner, or a pilot that lights and holds), then close the purge point. Wrong looks like gas odor spreading into the room, or gas still not arriving after a reasonable purge: stop, close that shutoff, ventilate at floor level, and check for a closed valve or blockage before trying again. Hazard: never purge into a basement, crawlspace, or closet; propane pools at floor level.

7. Relight each appliance and prove the flame. Follow the lighting instructions on each appliance's rating plate or label, one appliance at a time. Accept when the pilot or igniter lights, the flame proves, and the main burner lights smoothly with a stable blue flame and no rollout at the burner opening. Wrong looks like an appliance that fails to light after the number of tries its instructions allow, delayed ignition, or flame rolling out: stop cycling it (repeated tries load the combustion chamber with gas), close its shutoff, red-tag it, and treat it as a separate diagnosis. Hazard: keep your face and hands clear of the burner opening during ignition.

8. Verify pressure and combustion under load. With every relit appliance firing at once, measure inlet pressure at the appliance furthest from the regulator, and check manifold pressure against each rating plate. Wear a personal CO monitor and test ambient air near each fired appliance and the flue gas where the appliance has a test port. Accept when inlet pressure under full load stays within the appliance's rated range (commonly about 11 in. w.c. for propane), manifold pressure matches the rating plate, ambient CO reads zero, and flue readings fall within the manufacturer's limits. Wrong looks like pressure sagging below range under load or CO above zero in the living space: shut the affected appliance, red-tag it, and report the reading. A sag only under combined load is a supply-capacity question for the supplier. Hazard: stop work and ventilate if your CO monitor alarms.

9. Restore and hand off. Return thermostats and controls to the customer's settings. Show the customer the tank gauge and agree on a reorder point (30 percent is a common one, so a delivery delay does not cause another run-out), or recommend automatic delivery. Explain any red tag in plain words and leave it attached. Accept when the customer has seen every appliance running, knows which are tagged off and why, and has signed the record. Wrong looks like a customer who intends to remove a red tag: write their refusal on the record, tell the supplier, and do not relight the tagged item. Hazard: none new; confirm no appliance shutoff was left half open.

The record this produces

One record per visit, attached to the job in the work order system and copied to the customer:

• Tank gauge on arrival and after fill, supplier name, leased or owned, delivery time.
• Detector readings at step 1 by room.
• Appliance inventory with valve status, and any capped outlets.
• Leak-check method, test point, start reading, end reading, hold time, pass or fail, and every leak found with its repair.
• Each appliance relit: pass, or tagged with reason.
• Inlet and manifold pressures under load, ambient and flue CO.
• Red tags issued, customer signature, any refusal.

The office reads it to schedule red-tag follow-ups; the next tech reads it to know the system history; and if anything ever goes wrong at this address, it is the shop's proof of what was checked.

Worked pass

A ranch house, January. Leased tank, gauge at 2 percent on arrival.

1. Gauge 2 percent. Detector zero at floor level in the utility room, kitchen, and laundry. Customer says nobody relit anything. Pass.
2. Four appliances found by tracing and confirmed with the customer: furnace, water heater, range, dryer. Four valves closed. No uncapped branches. Pass.
3. Supplier fills to 80 percent at 10:40; driver confirms the service valve closed. Pass.
4. Regulator vents clear and pointing down. The range is on an old uncoated brass connector; noted for replacement, not flexed. Pass with note.
5. Manometer on the furnace inlet tap. Pressurized to 11.0 in. w.c., service valve closed, 3-minute hold per this shop's procedure. Reading fell to 9.5 in. w.c. in 3 minutes. Fail. Service valve closed. Leak-detector solution bubbled at the range connector's flare nut. Customer approved replacement; the tech installed a listed coated connector from truck stock. Step repeated: 11.0 in. w.c. at start, 11.0 after 3 minutes. Pass.
6. Each branch purged through its burner, kitchen and utility room windows open, no ignition sources. Steady gas at all four. Pass.
7. All four relit; stable blue flames, no rollout. Pass.
8. All four firing: inlet at the dryer (furthest) 10.8 in. w.c.; manifold pressures match rating plates; ambient CO zero; furnace flue CO within the manufacturer's limit. Pass.
9. Reorder point set at 30 percent; customer signed.

Step 4 had already flagged the failed part, which is why inspection comes before pressurizing. Relit straight after the fill, the range connector would have leaked into a kitchen with every appliance lit.

References

• NFPA 54, National Fuel Gas Code, Chapter 8 (leak checks and purging after restoring service), in the edition adopted by your jurisdiction
• NFPA 58, Liquefied Petroleum Gas Code, in the edition adopted by your state
• Each appliance's rating plate and installation manual, for lighting instructions and pressure ranges
• Your propane supplier's out-of-gas and leak-check policy, and your state's rules on who may perform it
• See related: Propane Homes: What Every Trade Should Know