Heater Error After New Gas Meter: Supply vs Pressure Decision Tree

Why this matters

A pool heater that worked fine starts throwing ignition or flame-failure errors right after the utility swapped or upgraded the gas meter. The timing points squarely at the gas supply, but "after the meter change" has several distinct causes: air left in the line, a regulator set wrong or a different delivery pressure, a partially closed valve, or simply that the heater was already marginal and the brief shutoff exposed it. Treating it as a heater fault and replacing parts when the real issue is supply pressure wastes money and leaves the customer cold. This tree separates a true gas-supply/pressure problem from a coincidental heater fault.

Gas work sits at the boundary of your scope. Anything upstream of the heater's gas valve, the meter, the regulator, the building gas piping, belongs to the utility or a licensed gas fitter, not the pool tech. The tree is about correctly attributing the fault and knowing when to hand off.

Symptom presentation

• Heater began faulting immediately after the utility replaced or upgraded the gas meter.
• Error codes consistent with ignition failure, flame loss, or low gas: the burner attempts to light and locks out, lights briefly then drops out, or never proves flame.
• Other gas appliances in the building may or may not also be affected (a clue to whether the problem is whole-building or heater-specific).

Quick checks

• Verify every gas valve the utility may have touched is fully open. A manual valve left partly closed after the meter swap starves the heater. Check the appliance shutoff and any valve at the meter.
• Check whether other gas appliances work normally. If the furnace, range, and water heater all run fine and only the pool heater faults, the problem is more likely at the heater or its branch; if multiple appliances misbehave, suspect whole-system supply/pressure.
• Confirm there is no gas odor. If there is, stop and follow the warning above.
• Reset the heater once and watch the ignition sequence. Air in the line after a meter change often clears after one or two purge cycles; a heater that lights on the second or third try and then runs clean was simply air-bound.

Isolation tree

Start: Do other gas appliances in the building operate normally?

• No, multiple appliances are affected. This is a whole-building supply or pressure problem, upstream of your scope. Hand off to the gas utility / licensed gas fitter. The meter swap likely left the system needing purge or a regulator adjustment, or delivery pressure changed. Do not modify gas piping or regulators.

• Yes, only the pool heater faults. Go to: Does the heater light briefly and then drop out, or never light at all?

  • Lights briefly then drops out (flame loss / proving failure). Suspect air in the gas line not yet purged, or marginal gas pressure at the heater's valve that holds long enough to ignite but not to prove steady flame. Cycle the heater a few times to purge residual air. If it stabilizes after a few cycles, it was air, common right after a meter change. If it keeps dropping out, the next step is a manifold gas-pressure reading.

  • Never lights (no ignition / lockout). Go to: Is gas reaching the heater at all?

    • No gas at the heater (valve clicks, no flame, other appliances fine). Confirm the appliance shutoff and the branch line valve are fully open. If open and still no gas, the branch may be air-locked or a valve upstream is closed. This crosses into gas-piping territory; if opening accessible valves and purging does not restore flow, hand off to a gas professional.

    • Gas reaches the heater but it will not prove ignition. Now you separate supply from heater. A manifold gas-pressure measurement (taken by a qualified person with a manometer at the heater's pressure tap) tells the story: pressure below the heater's rated inlet/manifold spec means a supply/regulator/pressure problem from the meter change, hand off upstream. Pressure within spec means the gas supply is fine and the fault is in the heater (igniter, flame sensor, gas valve, control board), unrelated to the meter except by coincidence of timing.

Confirming the diagnosis

• If the heater stabilizes after purge cycles, the cause was air introduced by the meter work. Confirmed and resolved.
• If manifold pressure reads below the heater's spec, the cause is gas-supply/pressure from the meter change; the correction is upstream (utility/regulator) and out of pool-service scope.
• If manifold pressure is within spec and the heater still faults, the heater has a genuine ignition-system fault; the meter timing was coincidental, and you diagnose the heater normally (igniter, sensor, valve, board).

Remediation

• For air-in-line: purge by cycling the heater per the manufacturer sequence until it lights and runs clean; verify steady flame and normal stack.
• For low manifold pressure: do not adjust regulators or gas piping yourself; document the measured pressure versus the heater's nameplate spec and refer to the gas utility or a licensed gas fitter.
• For a genuine heater fault confirmed by in-spec pressure: diagnose and repair the heater's ignition components per the manufacturer's fault-code procedure.
• Always re-verify safe, steady operation and check the venting before leaving; never leave a heater that proves flame intermittently.

References

• National Fuel Gas Code (NFPA 54 / ANSI Z223.1) on gas-line purging, appliance connection, and inlet/manifold pressure requirements.
• International Fuel Gas Code (IFGC) provisions on gas piping, valves, and appliance gas-pressure specifications.
• Pool heater manufacturer service manuals (Pentair MasterTemp, Raypak, Jandy/Hayward) for rated inlet and manifold gas-pressure specs and fault-code ignition diagnostics.
• Gas utility emergency-response guidance on suspected leaks and the licensed-professional scope boundary for meter, regulator, and building-piping work.