Fraser-Johnston
Marginal Venting or Pressure Switch Sensitivity
Furnace occasionally fails to start on very cold or very windy days.
Advertisements
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Advertisements
Possible Causes
Wind‑induced pressure at vent termination, Long or improperly terminated PVC vent, Weak inducer motor, Pressure switch setpoint too high
How to Fix / Troubleshooting
Safety first: Turn off power before modifying venting.
- Inspect vent termination: Ensure the vent and intake terminations meet Fraser‑Johnston installation guidelines (distance from corners, soffits, and grade). Wind can cause pressure fluctuations.
- Check for ice or snow: In cold weather, ice can form at the vent outlet. Clear any buildup.
- Consider vent kit or shield: A professional can install a wind‑resistant termination kit or shield if wind is a recurring issue.
- Have a technician test draft: Measuring pressure at the pressure switch port will confirm if the inducer and venting are marginal.
Advertisements
Repair Difficulty
Hard
4/5
Required Part
Vent Termination Kit
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements