Hvac venting in garage

I had an inspection yesterday that had a newer 90% plus heater. the venting had 2 PVC pipes coming off of it, but the intake was taking in air from the house. the exhaust pipe was outside but the wall had stains under it.
A) Is it normal to take air from a garage for a 90+ unit?
B) Is the stain under the exhaust pipe normal?

When you looked up the make and model number online and searched for the installation manual what did it say?

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If your talking about a furnace, no it is not normal for the exhaust termination to have condensate running out of it, staining the side of the house. If that’s the source of the staining.
Venting is pitched back to the furnace and drained or pumped out.
Most manufacturers recommend taking intake and combustion air venting to the exterior.

thank you for your help, i will be recommending an hvac contractor to come take a look at it.

That condensate is not coming out of the pipe (from improper slope). It is at the wall penetration.

As for combustion air from the garage, it’s fine.


Yossi. Try to post the model number and manufacture if you can. Need help, we are all her to assist you buddy. Model number is required so you/we can glean through the manufacturers installation instructions.

What type of HVAC? Mid or High Efficiency Condensing furnace or boiler?

Just a guess mind you but I think the elbow is loose and steam/ hot condensate is being dispersed back towards the wall.
Be it EIFS or Stucco, moisture will get between the wall assemble and cause problems.

Observation: Vent/flue termination. Staining encompases the venneer at Vent/flue termination/protrusion.
Suspect: Loose elbow causing condensate to be dispersed on the EIFS/Stucco veneer.
Recommend: A licensed HVAC contractor evaluate the High Efficiency Condensing furnace/boiler exhaust vent pipe. Seal the vent pipe at the wall assemble with an approved mastic.
Act upon any recommendations therein.