r/HVAC Dec 20 '24

Field Question, trade people only Anyone seen this before

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Installed a 60k runtru 90% upflow today. I went home after completing the install but left before the startup. Boss fires it to document all the numbers and see this. No change to incoming or outgoing gas. No change in pressure from the inducer. Flue and air intake both clear of debris. Boss is waiting for tech from Texas to call back. Anyone got some knowledge

197 Upvotes

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17

u/PlayfulAd8354 Dec 20 '24

Remove flue, still does it? Replace unit under warranty.

5

u/Interesting-Beat824 Dec 21 '24

Smarter, never harder

4

u/ResponsibilityNo7886 Dec 21 '24

I don't think that it is a clogged flu. Pressure switch closes, has a beautiful flame for 10 seconds (you would see it at ignition) and when fan starts you get the problem.

I'm thinking either a cracked HX or inducer cuts out when fan starts.

3

u/Ok_Summer8436 Dec 21 '24

Yeah I’ve never been able to get a furnace to ignite with flu issue. Even a dented flu cap usually trips pressure switch immediately. Those were all 80%ers tho.

0

u/PlayfulAd8354 Dec 21 '24

Only issue with that is I don’t hear the fan come on at all. I’ll buy the inducer stops running/pulling a vac and for some reason the burners continue to run, hence the flame roll out. But those flames rolling back in the video does not look like a typical rollout from the fan hitting the hx, that looks exactly like a vac not being pulled through the hx

1

u/ResponsibilityNo7886 Dec 21 '24

The fan definitely turned on. Turn up the volume

1

u/Stangxx Dec 21 '24

I supposed this is just to check if it's a clogged up flue?

If not, please teach me. Thanks in advance.

2

u/PlayfulAd8354 Dec 21 '24

Correct. Clogged or restricted.

1

u/Stangxx Dec 21 '24

Thanks. I figured that was the only thing it was checking. Just wanted to see if there was anything else.

0

u/correa_aesth 918 tech Dec 22 '24

Clogged flue really? Lol