My myson tankless water heater will not light-at all.

Thought it might be the thermocouple, but called in a heat/plumb guy to look at it and he tried lighting the pilot manually, but it would not light at all. He concluded that it was something else besides the thermocouple because if it were the thermocouple that was shot the pilot would light manually but go out right away. Then he was stumped because I don't have a manual for the unit and he is unfamiliar with tankless.

Is he right about his deduction that its something beyond the thermocouple?

Thanks for any help.

I still think it is your thermocouple.

Most tankless gas heaters have a safety in it. The safety is usually electric.

He tested the thermocouple in manual and it still wouldn't light. It may be clogged carefully clean the orific with a piece of fine wire.

If that does not work, the thermocouple is probably faulty. It will probably be fixed if you change the thermocouple.

If that doesn't fix it, you need to call a better heat/plumb guy, I hope he didn't charge you for doing half a job.

No pilot/ no fuel

I still think it is your thermocouple.

Most tankless gas heaters have a safety in it. The safety is usually electric.

He tested the thermocouple in manual and it still wouldn't light. It may be clogged carefully clean the orific with a piece of fine wire.

If that does not work, the thermocouple is probably faulty. It will probably be fixed if you change the thermocouple.

If that doesn't fix it, you need to call a better heat/plumb guy, I hope he didn't charge you for doing half a job.

No pilot/ no fuel

Thanks meredith1978. I'll try cleaning with fine wire and then change thermocouple if need be. No he didn't charge me, but I made sure to ask at the door if he would just for looking. Appreciate the tips much.