Heil furnace question

[Dave Rose]

Hello all,

I inspected a house yesterday and saw something new...

Had a Heil heat pump unit (it was 8 years old), but the seller said they didn't like the electric resistance heating as backup heat since it was too expensive, so they configured the heat pump emergency heat to run off their LP tank. I'd never heard of this before.

When I inspected the furnace, I noted that just past the burners, in the tubes, the "diffusers" were odd-shaped and actually looked like they were partly melted or something. It's difficult to describe, but imagine taking a sheet of metal, punching holes in it, then wrapping it in a cylinder...that's what they looked like...but then they were "eaten away" at the front end.

The flames came out of the burners blue, but when they hit those metal devices that I'm calling diffusers, they turned an orange color. I have already specified that they have an HVAC tech evaluate this, but I'm wondering for my own knowledge if anyone has seen this and what that setup is.

All photos below are of the same thing, just tried to get better lighting and focus.

Thanks,

Dave

28274 28275


28276 28277

[Jim Luttrall]

Very common in some areas to have "dual fuel" heat.
I can't help with the diffusers in the burner tubes but it looks to be factory installed and in need of attention from a tech. Good call.

[Jerry Shipman]

They are baffles installed to reduce the NOx emmisions, for use in areas that have special "low NOx" requirements. (mainly California).

These furnaces were constructed and configured from the factory for use with natural gas. Most likely, ( judging from the pictures and by the homeowner response to you) the furnace was converted to utilize propane by the homeowner, or someone without the knowlegable of the proper conversion steps.

The baffles should have been removed when the natural to propane gas conversion was performed, along with multiple other items that require change or modification.

Indeed, the furnace needs to be inspected and serviced by a qualified technician.

[Dave Rose]

Thank you Jerry, I did not know that...I just knew it didn't look right. Fortunately I did write it up as needing an HVAC tech to evaluate, but it's nice to know more...next time I'll be smarter.

Dave