FAQ
TL;DR: In this thread, 1/1 fixes came from replacing the feeder’s white relay; "the replacement of this relay really helped." [Elektroda, raf2, post #16694690]
Why it matters: If your Geco driver won’t start the feeder but other ports work, this FAQ shows a fast, safe relay-focused fix for DIYers and technicians.
Quick Facts
- Symptom: feeder won’t turn on, but the same device works when moved to a fan port. [Elektroda, raf2, post #16685658]
- Likely root cause: the white feeder relay has a burned contact. [Elektroda, jurek54, post #16689643]
- Electrical check: expect approx. 12 V DC across the relay coil when the feeder should run. Mains 230 V present—use caution. [Elektroda, Magister_123, post #16689632]
- Fast diagnosis: swap the fan and feeder relays; if the feeder starts, the original feeder relay is bad. [Elektroda, Magister_123, post #16689632]
- Field report: failure occurred after about 9 years of boiler/driver use. [Elektroda, raf2, post #16689864]
What most often causes a Geco feeder not to turn on while fan ports still work?
A failed feeder relay is the prime suspect. In this case, the white relay’s contact was burned, stopping power to the feeder. Replacing that relay restored operation. Other faults are possible, but the relay was the confirmed fix in the thread. [Elektroda, jurek54, post #16689643]
How can I quickly confirm a bad feeder relay without measurements?
Swap the fan and feeder relays on the driver board. If the feeder starts working after the swap, the original feeder relay is defective. This is a safe, fast A/B test before ordering parts. Revert the swap after diagnosis. [Elektroda, Magister_123, post #16689632]
How do I test the relay coil voltage safely?
Command the feeder to run and measure across the relay coil. You should see approximately 12 V DC at that moment. Remember, mains 230 V also exists on the board; isolate, use probes carefully, and follow lockout practices. “Be careful because you will also have 230V.” [Elektroda, Magister_123, post #16689632]
Which relay should I buy to fix the feeder output?
Buy an identical replacement for the white feeder relay on your board. A like-for-like swap resolved the burned-contact failure reported by another user. Match coil voltage, pinout, and footprint for drop-in fit. [Elektroda, jurek54, post #16689643]
Is age a factor here?
Yes. The reported driver had about 9 years of service when the relay failed. That points to contact wear from repeated switching as a plausible cause. This timeline can guide preventive replacement in similar units. [Elektroda, raf2, post #16689864]
Step-by-step: How do I replace the feeder relay?
- Power down, disconnect mains, and remove the driver board.
- Desolder the white feeder relay, clean pads, and solder an identical new relay.
- Reinstall the board, restore power, and test the feeder output.
A successful swap restored operation in the forum case. [Elektroda, jurek54, post #16689643]
I’m not confident opening the driver—should I attempt this repair?
If you’re unsure where the relay is or how to test it, seek a qualified technician. Disassembly and board-level work require skill and tools to avoid further damage. Safety and correct diagnosis come first. [Elektroda, Magister_123, post #16685993]
What tools do I need to diagnose or replace the relay?
You’ll need a multimeter, a soldering iron, solder, and a desoldering tool or braid. These allow you to test coil voltage, remove the faulty relay, and install the new part cleanly. Good lighting and magnification help. [Elektroda, Magister_123, post #16686327]
Is the relay always the culprit, or could it be something else?
Other faults can mimic relay failure. The thread notes cold solder joints or a damaged microcontroller as possibilities. “It may well be cold solder or a damaged microprocessor.” If relay tests pass, inspect solder and control signals. [Elektroda, Magister_123, post #16686327]
Why does the feeder work on a fan port but not on its own port?
That points to a problem specific to the feeder channel, not the motor. The working fan port proves the load and supply are okay, implicating the feeder relay or its drive path. Use a relay swap to confirm. [Elektroda, raf2, post #16685658]
Where is the feeder relay on the board?
It’s the white relay on the driver PCB. Users identified it as the feeder relay during troubleshooting. Look for discoloration or soot near that component, which can indicate contact wear. [Elektroda, jurek54, post #16689643]
What was the confirmed fix in this specific case?
Replacing the white feeder relay solved the issue. The original poster confirmed the repair after installation, closing the loop on diagnosis and solution. This validates the relay-focused approach. [Elektroda, raf2, post #16694690]
Any edge cases I should watch for after swapping relays?
If the problem persists even after swapping known-good relays, suspect a control-side fault. That includes cold solder joints on the relay drive or a damaged microcontroller output. Proceed with signal tracing. [Elektroda, Magister_123, post #16686327]
