Any HVAC Professionals In Here?

It runs without stopping with the door off (to the flame compartment). The left flame is perfect, a thin line of fire all the way into the heat exchanger. The right flame is a little rough with a tiny bit flicking the top of the ring the flame goes into it.

 

The flame looks fine, he said... No it doesn't.
Now it appears the combustion is incomplete for lack of fresh air. 2 things come to mind, the flue is partially blocked, or the draft inducer motor is getting weak. Check the vent exit for bird nests, wasps, etc.
There is a way to check the draft inducer, but it's not safe and I will not tell you how to do it.
IF you decide to swap the draft inducer assemblies, be aware you will need new gaskets.
And, you do have CO detectors in your house, right? Any home with fossil fuel heat should have them.

 

I actually ran a borescope down the exit pipe from the outside and did not see any blockages. I did it while the furnace was running and I felt the exhaust so I don't think there is a blockage, at least not a big one.
Yes I have a CO detector and I just tested it and I believe it is working.

 

How many other gas appliances run off this same gas line at the same time?

 

I only have two propane gas items, the furnace in question (basement) and the furnace in the attic.

 

Current flame with the door off, notice left is much tighter of a pattern.

 

That top pic, the burners are too hot.
Seems like a gas pressure to those burner orifices or a lack of air getting in for combustion.

 

This. If gas pressure was too high, both furnaces would be affected. Unless they have separate regulators, which I doubt.

 

ok, so if it's a lack of air, is that why it works 100% with the door off?

 

I was thinking more along the line of a spider getting in the orifices, that will cause a restriction in gas flow to specific burners.

 

No, the door off lets more ambient air to the rollout switch, keeping it somewhat cooler.

 

That is a possibility. Pull them and check. Then swap side for side and see if the flame change follows?

 

Thanks all for the help. I wanted to try all the possible DIY fixes first but it looks like I need to call a professional.

 

Good luck! Let us know what the fix is.

 

Did anyone else notice the OP says "propane" but the furnace info placard says natural gas? Is there a tank in the yard?

 

He has probably had it converted to run on propane.. at least I hope he has.

 

I assure you it has been converted. The flame would be a giant yellow flame. Seen that once on a call from a know it all that installed his own gas furnace. And he had the conversion kit but didn't think he needed to install it. I laughed, he got pissed, I walked away. Being you own boss has perks, sometimes, but I didn't make any money off that call.
Worth it!

 

Any update on the furnace repair?

 

Holes in the Heat Exchanger, 2 small ones, 1 large one. When the old one was removed the guy circled them with a black sharpie and showed me. Installing a new American Standard. Appreciate all your help!

$1617 wholesale price for unit and pipes etc.
$1500 labor which includes servicing the other unit in the attic and ACs.