Stable 3.6 A Constant Current Source for Automatic Gas Valve Testing
Recently, we had a customer who manufactures automatic gas valves come to us looking to replace their outdated constant current source test equipment, model B534 1500S-CR by Powertron. This equipment is a 1500-watt unit, weighing roughly 225 lbs, and can only power up to 10 of their gas valves at once due to its output current and voltage range constraints. Each valve is rated for 3.3 VAC, 3.6 A.
Many safety-certified automatic gas valves are designed to open reliably when the coil current reaches a specified value (typically up to 3.6 A). Because of this safety design, gas valve manufacturers need constant current source test equipment to provide steady current and verify that their valves meet the 3.6 A safety compliance requirement.
At Amp-Line Corp, we manufacture constant current sources specifically designed for this type of testing. Our AC constant current sources (CC-Series) are available with power ratings ranging from 50 W to 1200 W, with other wattage options available as well. The available power determines how many valves can be tested at the same time.
Most importantly, the output ranges of our constant current sources are customizable to better meet our customers’ testing needs. For example, our 300-watt unit, with a custom output current of 0–5 A rms. at 60 V rms. compliance voltage, can power at least 16 gas valves (rated for 3.3 VAC, 3.6 A) at once. Our 1200-watt unit, with a custom output current of 0–5 A rms. at 240 V rms. compliance voltage, can power at least 65 valves (rated for 3.3 VAC, 3.6 A) at once.
With these customized output ranges, both our 300-watt and 1200-watt units can test significantly more gas valves compared to Powertron’s test equipment, model B534 1500S-CR. They are also lighter, more compact, and more power-efficient, which helps save valuable power and rack space. Our AC constant current sources ensure that gas valves are tested under stable and repeatable electrical conditions, helping verify that their safety mechanisms operate exactly as intended.
How Automatic Gas Valves Use Current to Ensure Safe Ignition
Most automatic gas valves contain a solenoid actuator. A solenoid valve works by passing electrical current through a coil of wire, which generates a magnetic field. That magnetic field moves a small metal plunger that opens the valve and allows gas to flow.
In many gas appliances, the solenoid valve is connected in series with a hot-surface igniter (HSI). Because they are wired in series, the same current flows through both the igniter and the valve coil.
When power is applied, the igniter begins to heat up. As it heats up, the electrical characteristics of the circuit change, and the current gradually increases. Once the current reaches approximately 3.3–3.6 A, the magnetic force in the valve coil becomes strong enough to open the valve. This design ensures that gas cannot flow until the igniter is hot enough to ignite it.
This design prevents raw gas from being released when ignition cannot occur, which greatly reduces the risk of gas accumulation.
Ultimately, accurate current control is what makes this entire process work. That’s exactly why we focus on building constant current sources that deliver stable, repeatable performance—so manufacturers can test with confidence.
Many safety-certified automatic gas valves are designed to open reliably when the coil current reaches a specified value (typically up to 3.6 A). Because of this safety design, gas valve manufacturers need constant current source test equipment to provide steady current and verify that their valves meet the 3.6 A safety compliance requirement.
At Amp-Line Corp, we manufacture constant current sources specifically designed for this type of testing. Our AC constant current sources (CC-Series) are available with power ratings ranging from 50 W to 1200 W, with other wattage options available as well. The available power determines how many valves can be tested at the same time.
Most importantly, the output ranges of our constant current sources are customizable to better meet our customers’ testing needs. For example, our 300-watt unit, with a custom output current of 0–5 A rms. at 60 V rms. compliance voltage, can power at least 16 gas valves (rated for 3.3 VAC, 3.6 A) at once. Our 1200-watt unit, with a custom output current of 0–5 A rms. at 240 V rms. compliance voltage, can power at least 65 valves (rated for 3.3 VAC, 3.6 A) at once.
With these customized output ranges, both our 300-watt and 1200-watt units can test significantly more gas valves compared to Powertron’s test equipment, model B534 1500S-CR. They are also lighter, more compact, and more power-efficient, which helps save valuable power and rack space. Our AC constant current sources ensure that gas valves are tested under stable and repeatable electrical conditions, helping verify that their safety mechanisms operate exactly as intended.
How Automatic Gas Valves Use Current to Ensure Safe IgnitionMost automatic gas valves contain a solenoid actuator. A solenoid valve works by passing electrical current through a coil of wire, which generates a magnetic field. That magnetic field moves a small metal plunger that opens the valve and allows gas to flow.
In many gas appliances, the solenoid valve is connected in series with a hot-surface igniter (HSI). Because they are wired in series, the same current flows through both the igniter and the valve coil.
When power is applied, the igniter begins to heat up. As it heats up, the electrical characteristics of the circuit change, and the current gradually increases. Once the current reaches approximately 3.3–3.6 A, the magnetic force in the valve coil becomes strong enough to open the valve. This design ensures that gas cannot flow until the igniter is hot enough to ignite it.
| Igniter Condition | Circuit Current | Gas Valve Action |
| Igniter cold | Low | Valve closed |
| Igniter heating | Increasing | Valve closed |
| Igniter fully hot | ~3.3–3.6 A | Valve opens |
This design prevents raw gas from being released when ignition cannot occur, which greatly reduces the risk of gas accumulation.
Ultimately, accurate current control is what makes this entire process work. That’s exactly why we focus on building constant current sources that deliver stable, repeatable performance—so manufacturers can test with confidence.