HVACopediaAllied · Furnace troubleshooting
Keep the furnace away from contaminated combustion air
What is going on
Exposure to certain chemicals in the combustion air causes safety and performance problems, heat exchanger rusting and early failure.
Likely causes
- Chlorinated waxes, cleaners or swimming pool chemicals
- Water softening chemicals, de-icing salts or chemicals
- Halogen refrigerants, carbon tetrachloride or solvents such as perchloroethylene
- Paint removers, varnishes, printing inks, cements, glues
- Hydrochloric or masonry acid washing materials, antistatic dryer softeners, permanent wave solutions
Check in this order
- Check the combustion air supply for the listed substances before installing.
- Do not install the furnace in a corrosive or contaminated atmosphere.
- Use outdoor air for combustion where indoor contaminants are present.
- Meet all combustion and ventilation air requirements and local codes.
Applies to: All installations
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Source: Allied 92G1UH installation instructions manual, p. 10. Written in our own words; check the manual for your exact model.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.