Tankless Water Heater Improper Venting or Not?

Hey guys,

I did a home inspection on a condo/townhouse back in early May. The client says the utility company red tag the tankless water heater due to gas leak resulting from improper venting. A plumber inform the client the tankless water heater vent should be PVC instead of the Steel Vent. Plumber recommended to correct this action by installing a new pvc vent pipe. Is this correct?

Does the vent material make a tankless water heater venting system improper? Does this fall within the Standards of Practice for a home inspector to identify as improper on our reports?

I did some research on the manufacturer installation instructions. Some models recommend steel and others PVC material.

Tankless Water Heater Bosch 2 Tankless Water Heater Bosch201111161534160.BoschDWVentingCatalog_77799307_102011 (2).pdf (2.7 MB)

You have two issues. First, it’s not a gas leak but rather a combustion gases leak. Second, you are dealing with a condensing, positive pressure venting appliance or category 4 appliance. If you look again at the manual you have posted, you will note that steel is only allowed with non condensing units. So… a PVC must be used and because it’s a positive pressure venting the PVC must be sealed… what you have in the picture is not a sealed vent and thus it leaks combustion gases back into the room. You should read up on this not to get yourself further in trouble. Whoever installed it, if not the homeowner, is a complete hack. Good luck :slight_smile:



Quintavius, you need to google the exact make and model installation instructions to get your answer.

Thanks for the feedback. Much Appreciated!