FieldBench

Bryant

916S

Furnace · Legacy · single-stage · 96/97% (912S is 92%)

Bryant Legacy Comfort-style 96/97% single-stage (915S is the previous plate; 912S is the 92% cousin). Two-digit IFC. One pressure switch. Fixed-speed or 18-speed blower — not Preferred VS, not Evolution ABCD. Field reports of 33/34/13 on 915SB are this family.

Not 926S Preferred VS single-stage (InteliSense, 25-speed). Not 926T two-stage. Not 800S (80% metal vent — same 31 number, no PVC trap).

Walk this in Diagnose

This plate

AFUE
916S up to 97% · 915S ~95–96% · 912S up to 92.1%
Staging
Single-stage · one PS · one inducer speed
Blower
Fixed-speed or multi/18-speed — not Preferred 25-speed VS
Control
Two-digit Comfort/Legacy IFC · 24V W G Y R C

This board

Legacy / Comfort two-digit IFC

  • 11–14, 21–24, 31, 33, 34. Same Carrier Comfort 59SC5 language.
  • One draft switch. 31 is that switch. 32 on the door, if printed, is still the only PS.
  • 912S is 92% condensing — still a collector/trap, still not an 80% chimney.

Sequence

  1. W. Inducer → single PS → HSI → valve → flame → blower on the selected heat speed.

Faults on this IFC

  • 13 / 33

    Limit

    warn

    Airflow or rollout. 13 after ~3 min of 33.

    • Heat-speed tap / 18-speed setup, filter, coil.
    • 915SB 33 is the same winter call as Carrier 59SC5.
  • 14 / 34

    Ignition

    lockout

    No flame prove.

    • HSI, gas, rod, ground. 34 then 13-style lockout 14.
  • 24

    Fuse

    warn

    24 V fuse.

    • Tstat short, HUM, valve harness.
  • 31

    PS / draft

    lockout

    The only switch did not close.

    • Trap, collector, PVC, wind, inducer. 912S still has a 92% collector — not a chimney.

Workflows

33 on a 915S / 916S

Heat works, then drops. Classic Legacy callback.

  1. This blower is not 926T VS model-plug CFM. Read the heat tap / 18-speed setting.
  2. Filter and the A-coil. Legacy jobs often got a thick media cabinet.
  3. If rollout is the open part of the 33 circuit, stop and inspect. Do not keep resetting.

Test points

Single PS
One NO switch. Closed only with inducer up.
Heat speed
Tap / 18-speed vs rise on the plate. Not a 926T plug.

Gotchas

  • 915S is the plate you will see on 2010s jobs. 916S is the current Legacy 97%. Same chart.
  • 912S is 92%, still condensing — do not treat 31 as an 80% chimney.
  • Carrier 59SC5 is the factory twin language.

Related plates

  • carrier-59sc5 — Carrier Comfort 96 single-stage parent. Same 31/33/34.
  • bryant-926s — Preferred single-stage VS. Same one-PS idea, different blower.
  • bryant-800s — Legacy 80% single-stage. Same 31 number, metal vent, no trap.