We got called out to service an appliance that was red tagged by the gas company this week.
PSE had disconnected a Rinnai Tankless water heater that was discharging 435 PPM of CO into the OUTSIDE air. (400 PPM is the legal limit).
We had not run into this situation before. We know that CO is dangerous in the house but we had no idea that there were federal laws related to residential gas appliances and outdoor air quality.
Well, we contacted the manufacturer asking for the technical service specifications so we could fine-tune the appliance to comply with the EPA requirements. It turns out that the appliance was not adjustable. All we could do was insure that the unit was burning blue and had a clean combustion chamber.
We see some risk to our customers with some tankless water heaters that are not compliant with EPA air standards.The gas company may disconnect the appliance with no recourse except to replace the appliance with one that complies.
We are researching the options. It appears that some tankless water heater models should not be purchased.