FAQ
TL;DR: Troubleshooting TERMET G19‑02 no‑ignition? Start with 2 safety sensors and wiring; "If it doesn't get voltage, it won't open the valve." Check sensor continuity, coil drive, and loose connectors before suspecting the valve or gas block. [Elektroda, wiertacz, post #17279876]
Why it matters: This FAQ helps G19‑02 owners fix main‑burner ignition faults quickly and safely without unnecessary part swaps.
Quick Facts
- The ignition “module” integrates spark, flame sensing, solenoid control, and battery monitoring in the G19‑02. [Elektroda, wiertacz, post #17293714]
- Two contact‑type cutouts: a heat‑exchanger thermostat and a flue/draft sensor; an open circuit blocks ignition. [Elektroda, wiertacz, post #17291849]
- Measured coil voltages: orange ≈1.1 V; green 0.01 V when failing, ≈1.1 V after tapping/vibration. [Elektroda, Devet, post #17270712]
- Continuous sparking with water closed points to the water‑unit microswitch/needle; edge case: faulty module. [Elektroda, wiertacz, post #17277814]
- If tapping restores ignition, suspect loose connectors or broken conductors, especially the electrode lead. [Elektroda, wiertacz, post #17293714]
How do I fix a TERMET G19‑02 that wont light the main burner?
Check for loose cables to the control module and both safety sensors. Verify the heat and flue/draft sensors are closed at room temperature. An open sensor prevents the controller from energizing the main burner. Measure drive at the gas valve coils during a call for hot water. No voltage means the controller never commanded opening, so the coil itself is not at fault. Correct wiring or sensor issues first, then reassess ignition. [Elektroda, wiertacz, post #17279876]
What coil voltages should I expect on the G1902 solenoids?
Reported measurements: orange coil ≈1.1 V. Green coil reads ≈0.01 V when the burner fails to ignite, then ≈1.1 V after the unit is tapped and ignition proceeds. These figures point to intermittent control or contact issues rather than a bad coil. Use them as diagnostic references while checking wiring and sensors. [Elektroda, Devet, post #17270712]
Why does tapping the heater or water tube make it start?
Vibration often restores a poor electrical contact. If tapping makes the burner ignite, suspect a loose connector, oxidized pin, or a broken conductor near the module or electrode lead. Less commonly, your earlier description might mask a mechanical gas‑block issue. Inspect and reseat plugs before replacing parts. [Elektroda, wiertacz, post #17293714]
What does the flame monitoring electrode do, and how do I check it?
The electrode confirms flame; without confirmation, the controller blocks the main burner. "If the electrode does not confirm the presence of a flame... the controller will not allow the main burner to be started." How‑To: 1. Clean the electrode tip gently and dry it. 2. Inspect the entire lead to the module for damage. 3. Reseat the lead at the module and ensure a firm connection. [Elektroda, wiertacz, post #17270823]
How do the safety sensors work on this model?
"Temperature sensors are contact. After exceeding the appropriate temperature, the contact inside them opens and breaks the circuit." The system also uses a flue/draft cutout that opens on unsafe conditions. Either open contact prevents the controller from enabling the main burner. Check their continuity when cold, and never leave them bridged. [Elektroda, wiertacz, post #17291849]
Can I bridge the sensors to test ignition safely?
Brief bridging can show if a sensor contact is open, but it is not a fix. If bridging does not restore reliable ignition, suspect a bad connector at the module or a fault inside the module. Remove any bridge after testing; restore normal safety function before further operation. [Elektroda, wiertacz, post #17291849]
My igniter sparks constantly with water closedwhats causing it?
This symptom points to the water‑unit microswitch or the actuating needle sticking. Verify the battery is inserted correctly first. If the switch or needle is faulty, the module may see a false demand and keep sparking. In an edge case, a damaged control module can also cause continuous sparking. [Elektroda, wiertacz, post #17277814]
Pilot lights but the main burner takes minutes or only after blowingwhat should I check?
Inspect the draft/flue safety sensor and wiring, because airflow conditions influence its contact. An open draft sensor will block the main burner, causing repeated ignition attempts. Also check for loose connections to the module that vibration or airflow might temporarily stabilize. Correct contacts before suspecting gas hardware. [Elektroda, wiertacz, post #17279876]
Is the coil faulty if theres no voltage on the green coil?
No. Lack of drive voltage means the controller is not energizing the valve. "If it doesn't get voltage, it won't open the valve." Focus on upstream causes: safety sensors, wiring faults, or the control module. Test sensor continuity and harness connections first. [Elektroda, wiertacz, post #17279876]
What exactly is the spark generator on the G19102?
"The module is not just a spark generator." It contains the flame‑presence electronics tied to the monitoring electrode, solenoid valve drivers, and a battery‑wear monitor. Faults in this module or its connectors can block main‑burner ignition even if sparking occurs. [Elektroda, wiertacz, post #17293714]
Quick 31 isolation: coil, sensors, or module?
- Cold check: both safety sensors must read closed; fix any open contact. 2. Call for hot water and measure coil drive; no voltage means a control‑side problem. 3. Wiggle harness and module plugs; if ignition returns, repair the connector or lead. Persistent no‑drive with good sensors points to the module. [Elektroda, wiertacz, post #17279876]
When should I replace the ignition/control module?
After confirming sensor contacts, wiring integrity, and lack of coil drive, swap in a known‑good module. "It would be most convenient to replace the module for testing," which cleanly distinguishes module faults from wiring or sensor issues. [Elektroda, wiertacz, post #17295382]
Could the issue be mechanical in the gas valve unit?
Yes, if electrical contacts and sensor logic check out, consider a mechanical problem in the gas unit. However, vibration‑sensitive fixes usually implicate wiring or module connectors. Rule out loose or oxidized contacts before dismantling the gas block. [Elektroda, wiertacz, post #17293714]
Does battery orientation or quality matter for ignition?
Yes. Incorrectly inserted batteries can prevent operation or cause erratic sparking. Confirm polarity and seating after replacement. If sparking persists with the water off, check the microswitch and actuating needle next, and only then the control module. [Elektroda, wiertacz, post #17277814]
