Rusty Furnace where the exhaust exits

[tbird]

I ran into this today. It is a roof mount gas pack (bundled gas heater and A/C in one unit). There was considerable condensation coming from the exhaust area. The condensation was either rusty or the unit is rusting, I am not positive which was which. Is this an indicator of anything? I have seen slight rust before, but not this much. 80% effecient, low humidity on average (10-20%). Thanks for your help.

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[hausdok]

Hi Carl,

Is there any way for that exhaust to be leaking just inside the housing so that acid is able to condense inside the housing and drain down the sides causing that rust?

OT - OF!!!

M.

[tbird]

Originally posted by hausdok

Hi Carl,

Is there any way for that exhaust to be leaking just inside the housing so that acid is able to condense inside the housing and drain down the sides causing that rust?

OT - OF!!!

M.

Hey Mike,

I don't think that is the case. All the rust appears to be on the outside of the housing only. Would a damaged heat exhanger cause this? It could just be a rusting exhaust cover streaking down the unit?

[Bain]

Or the condensate drain could be clogged and rusty water is seeping out of the evaporator coil seams. Is the coil above what we're seeing?

[tbird]

Originally posted by Bain

Or the condensate drain could be clogged and rusty water is seeping out of the evaporator coil seams. Is the coil above what we're seeing?

The coils and pan sit low (see the condensate line on the first picture, right side). Sorry, I thougth I took a picture of the actual exhaust outlet but I cannot find it. It is only a metal shield over the exhaust opening. Kind of like this =]

[Scottpat]

If it is an older unit with a cast iron heat exchanger it could very well do that.

It looks like it is sitting on a 20 degree slope, I'm sure that is just the angle you took the picture.

[tbird]

Originally posted by Scottpat

If it is an older unit with a cast iron heat exchanger it could very well do that.

It looks like it is sitting on a 20 degree slope, I'm sure that is just the angle you took the picture.

I was tilted when taking the pictures. The date on the unit is a 1998.

Thanks

[Scottpat]

Originally posted by tbird

Originally posted by Scottpat

If it is an older unit with a cast iron heat exchanger it could very well do that.

It looks like it is sitting on a 20 degree slope, I'm sure that is just the angle you took the picture.

I was tilted when taking the pictures. The date on the unit is a 1998.

Thanks

It could be a cast iron heat exchanger if it is a 1998 model. That is what I would put my money on. Have an HVAC contractor remove the cabinet and inspect the heat exchanger.