The multimeter. Episode fifty-nine of the Gas Service Animated series.

Everything the last four episodes taught comes down to four measurements: volts AC, millivolts DC, ohms, and microamps. One meter, four settings, and a method. This is the episode that turns the theory into hands.

Volts AC is your presence test. Line voltage feeding the appliance; twenty-four volts leaving the transformer; twenty-four arriving at the valve. And the chain-walk from the circuit episode: across every safety switch, zero closed, twenty-four across the open one. AC voltage answers 'is the power where it should be' — the first question of every electrical call.

Millivolts DC is the standing-pilot world. Thermocouple: about thirty open, twelve to fifteen under load through the adapter. Thermopile: the seven-fifty family, three-fifty loaded as the floor. Give the junction time to heat, test at the terminals, and let the chart on the manual set the exact judgment line.

Ohms is the dead-circuit tool — and the rules are absolute: power off, component isolated. Igniters against their spec — silicon carbide up around forty to ninety, nitride eleven to twenty. Gas-valve coils against theirs — an open coil is a dead valve. Switch continuity when you must, though voltage-across beats pulling connectors. Ohms on a live circuit lies to you and can kill the meter.

Microamps DC is the flame's own signature. In series with the flame-rod lead, one to ten microamps healthy, dropout under about one. It's the only measurement here where the meter becomes part of the circuit — wire it in line, not across, and read the proof the board reads.

Meter safety is not optional. Use a meter rated for the environment — the CAT rating on its face. Keep fingers behind the guards, leads in the right jacks for the mode, and never switch to ohms or amps while connected to a live circuit. A gas appliance adds one more rule: you're measuring next to fuel — no sparks from careless probes near an open valve train.

The classic mistakes, so you can skip them: ohming a component that's still in circuit — the parallel paths lie. Testing a thermocouple cold. Forgetting the meter's own fuse after an amps mishap. Trusting continuity beeps where a voltage test under load would tell the truth. And condemning parts before checking the simple thing: connections.

The method that ties it together: start where the power starts, follow the diagram, measure — don't guess. Presence with volts, integrity with ohms, proof with microamps, millivolts for the pilot world. Every reading either matches the spec or points at the fault. That's the whole craft: restore the numbers.

The meter in one breath. Volts AC for presence — zero across closed, supply across the break. Millivolts for pilots. Ohms only dead and isolated — igniters and coils against spec. Microamps in series for flame proof. Respect the CAT rating, and let the diagram lead. That's the electrical season: from a whisper of millivolts to a proven flame.