Impacts of High Efficiency Gas

Furnace Condensate on Septic

Systems

Combustion of Low Efficiency FurnacesCO2 H2O NOX

• Older Design

• Pollutants to Atmosphere

• No Damage to Septic

Not the same for High Efficiency Furnace

Natural gas or Propane furnaces

Combustion results in fluid or condensate forming

Propane or Methane + Oxygen >> Water + Carbon Dioxide

(C3H8) or (CH4) + O2 > H2O + CO2

Chemical Processes

N2 + O2 + Heat >

NO2 + NO + H2O >

HNO3.H2O

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Combustion of Hi Efficiency Furnaces

Condensate

• Fluid or Condensate Forms

• Directed to sewage system

• 4L (1 US gal) per 100,000 BTU per

hour

• Damage to Septic

Example

As an example a 150,000 BTU furnace or boiler running approximately 8 hours

a day in the winter months would produce roughly 50L or 11.1 IG of

condensate

150, 000 BTU /hr x 8 hr = 48 litres / day

Volume of Damage

Equals to 2 five gallon buckets

per day of condensate going into

septic system.

pH Scale

The pH scale is not linear, it is logarithmic

Each whole pH value below 7 is 10 times more acidic than the previous value

Image: Bernansconi at www.mechanical-hub.com

A pH of 4 will cause damage

▪ Drainage pipes

▪ Septic tanks

▪ Treatment plants

▪ Other materials handling wastewater

Volume of Damage

Condensate is Corrosive

Low pH

Photos: Bernansconi at www.mechanical-hub.com

pH Tests of Condensate

As low as 1.8 to 2.0

Odorant added to natural gas

Propane and sulfur dioxide

Sulfur dioxide increases acidity

Example - Filters

Example - Filters

Example - Filters

Example - Filters

There is a simple solution…

Install a Neutralizer

Neutralizer

• Inexpensive

• Available at hardware stores or wholesale plumbing suppliers

• EMCO, Corix, Home Depot

• Self Regulating – will not dissolve in non-acidic fluids

In Conclusion

• Confirm if HE Furnace in is installed with homeowner

•Take necessary precautions

•Add neutralizer to design of project

Questions?