Bryant Furnace Code 31.7
WarningShown as: Major code 31 on the LED (3 short, 1 long); 31.7 on the display
High heat only for the next cycle - the high-heat pressure switch failed to close within 75 seconds while transitioning from low to high heat.
Manual wording: “31.7 HIGH HEAT ONLY for next cycle- HPS failed to close in 75s when transitioning from low to high heat.”
Documented for: 926TC
Likely causes, most common first
- Same venting and pressure switch causes as code 31.6
What you can safely check yourself
- Check outdoor vent terminations for blockage
- Check the condensate drain for a clog
When to call a technician
If the furnace keeps forcing itself to high heat, have a technician check the high-heat pressure switch and venting.
A Bryant furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- Installation, Start-up, Operating and Service and Maintenance Instructions - 926TC (Bryant Heating & Cooling Systems, 926TC Preferred Series two-stage, variable-speed ECM multipoise condensing gas furnace) · checked 2026-08-25