Burner not Firing

[Mike Lamb]

I inspected two Lennox furnaces in the same building. Both are the same age and model installed at the same time by the same guy. The far left burners did not fire on either one. Might someone intentionally do this and for what reason?

Coincidence?

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[Chad Fabry]

It's hard to get anything on the far left to work. Boom cha.

Spiders?

[Bill Kibbel]

1. Damaged/bent or clogged ignition crossovers.

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2. Clogged orifices.

3. Low gas pressure.

If it's the last burner after the valve on each furnace, I would investigate #3 first.

[MMustola]

Chad, That was funny!

[AHI in AR]

Chad, That was funny!

Yeah. I damn near did a spit take.

[Marc]

Chad, That was funny!

Yeah. I damn near did a spit take.

Somebody tell me this isn't going to morph into 'The Interview'.

Marc

[Tom Raymond]

Spiders like the oriface tube on my antique oven burner. I have to clean them out at least once a year. The burner fires but its a sooty smelly affair. It would have to be a pretty big spider to completely block that tube.

[Brandon Whitmore]

I'd say he's got the end orifice/ opening capped off. Otherwise, the flame rod you see on the functional far left burner would probably be placed @ the inoperative burner further left. At least most of them are.

Typically, the heat exchanger opening is capped when not in use though....

They're taking a 80k btu furnace and turning it into a 60k btu unit.

That flame rod proves flame for the burner "circuit". It needs to be @ the furthest burner over from the ignitor so that if all burners don't ignite, the gas valve closes. Otherwise, there'd be a risk for delayed ignition, which can be quite fun.

I tried to come up with a more clear explanation, but keep getting side tracked.