Help with Trane XE 90 furnace

Had this Trane XE 90 furnace today. Notice all the rusting. what is causing this? also on the outside the icicle on the exhaust. Can I get your opinions on this. Let me know what more info you need.
Model # TUX080C942C1 Serial # P443H3F7G
I assume it was made in 1999.






Poor installation of the air intake / exhaust piping will cause this.
Blockage of the drains would be indicated by more extensive corrosion.

defer back to the Contractor that installed the system (maybe still under warranty) to correct

Where is the condensate from the furnace and A/C draining to??? The piping is there but where is the drain exit?

It runs to a floor drain.

Is it at the low point of the drainage piping? Does it run towards the rear of the cabinet on the right side? Sure looks to be the result of backed-up / leaking condensate which is quite corrosive. Improper drainage would also leave more vapor in the exhaust which could contribute to the icicles on the exhaust.

Hi everyone. I have the exact same furnace and after 15 years it is now exhibiting the exact same problem as described at the beginning of this post. There were no issues with rust or dripping condensation before this year. The condensate appears to be dripping out from behind the blower motor assembly. I removed and cleaned all the drain pipes and the problem persists. Any help or advice would be appreciated.

Short answer, call a tech qualified on high efficiency gas furnaces to diagnose and repair.
The leak is probably coming from the connection to the condenser, the final heat exchanger that cools the exhaust so that water is changed from vapor to liquid. Need to eliminate the cooling coil and humidifier if there is one as a source, but it is almost certainly coming from the furnace condenser.
Re the icicles, pretty typical for this type of furnace if the conditions are right, I won’t say it is OK, because it could be a problem, but as far as I know it hasn’t been solved yet.
FYI if either the combustion intake or exhaust are blocked the furnace has safety sensors that will prevent it from working.