FieldBench
Models
Bryantfurnace

916S

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).

Diagnose this modelInstall notesBoard cross-refField wiring

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.

Write the two digits before power is pulled. 11 = no history.

Universal swap

Read the silk

This is the Bryant plate where ICM282B / 50M56U actually apply — if the silk is HK42FZ004–016/034.

Silk: HK42FZ004 · HK42FZ007 · HK42FZ008 · HK42FZ009 · HK42FZ011 · HK42FZ013 · HK42FZ016 · HK42FZ034

White-Rodgers

  • 50M56U-843

    WR kit lists HK42FZ004/007/008/009/011/016 — not 013, not an 11-pin bar.

ICM

  • ICM282B

    ICM for HK42FZ004/007/008/009/011/013/016/034. 013 is on this list (not on 50M56U).

  • ICM2812

    ICM2812 / 2812-KIT is the 50M56U-843 twin when you want the ICM carton.

Honeywell

  • S9200U1000

    Only if the silk is already a 50A50 / 50A55 (S9200U lists 50A55-843). Not an HK42FZ drop-in.

  • HK42FZ017 two-stage (ICM2807) unless that is the silk.
  • Evolution 987M / 986T. 926T VS two-stage.
  • 50A55-843 onto a VS motor if this cabinet was upgraded — read the motor plug.

After you pull the dead card

  1. 1Kill power. Photograph the silk-screen part number on the dead board before you pull it.
  2. 2Match staging (1 vs 2 vs modulating), igniter (carbide / nitride / spark), and motor (PSC / ECMx / 9-speed tap / serial VS).
  3. 3Set heat-off delay and any 80+/90+ jumper to the door card. Prove one full try and flame µA before you leave.

Field wiring

Written landings for Bryant 916S. Not a factory schematic.

Furnace · single-stage 24V
R / C / W / Y / GGas furnace

Conventional single-stage furnace IFC. One W. Cool Y passes through to the outdoor. No ComfortBridge, no ABCD, no W2.

Written circuit description only — FieldBench does not redraw maker schematics. Example: R to W closes on a heat call; verify 24V at W1 before you change the IFC.

Open manufacturer PDF

Heat sequence

  1. 1Power. L1 / N → IFC → transformer → R120V in, 24V out
  2. 2Call. Stat W → IFC W~24 VAC
  3. 3Draft. IFC → inducer → PS close120V motor, 24V prove
  4. 4Ignite. IFC → HSI120 VAC
  5. 5Gas. IFC → valve~24 VAC
  6. 6Flame. Rod → IFCµA DC
  7. 7Blow. IFC → heat speedAfter flame prove

This indoor

Legacy 96/97 single-stage.

24V single-stage heat

Door card is one-stage. Twin terminal empty unless the job is actually twinned.

Wall thermostat

Single-stage heat/cool. W2 from a leftover two-stage stat does nothing useful.

  • R24V hot from the IFC24V
  • CCommon24V
  • WHeat24V
  • YCool — also starts the outdoor24V
  • GFan24V

Furnace IFC

Transformer lives here. Y out to the outdoor contactor. TWIN empty on a standalone.

  • RHot to the stat24V
  • CCommon — must reach the outdoor24V
  • WHeat call24V
  • YCool in / cool out24V
  • GBlower24V
  • TWINEmpty unless twinned24V

Landing

  • 24VIFC Rstat R

    ~24 VAC hot

  • 24VIFC Cstat Coutdoor C

    Common

  • 24VStat WIFC W

    Heat. Stays in this cabinet.

  • 24VStat YIFC Youtdoor Y

    Cool / contactor

  • 24VStat GIFC G

    Fan. Does not go outdoors.

IFC harness — single-stage heat

After W arrives. This is the gas train, not the thermostat strip.

Transformer + fuse

120V primary. 24V secondary. Dark stat = fuse / door / transformer first.

  • L1 / N120V to the IFCLine
  • XFMR24V to R24V
  • FUSEOn the IFC24V

24V safety chain

Door, limit, rollout in series. Open anywhere kills heat.

  • DOORInterlock24V
  • LIMITMain limit — rise / no airflow24V
  • ROLLOUTManual reset. Do not jumper and leave24V

Inducer + one pressure switch

W → inducer 120V → PS closes → IFC continues. One hose, one switch.

  • IND120V from the IFC to the inducerLine
  • PS24V prove back to the IFC24V
  • HOSESingle hose. Do not add a second because two-stage boards have two.24V

HSI + single valve

Igniter is 120V from the IFC. Valve is 24V. Flame rod is µA DC back to the IFC.

  • HSI120V hot-surface igniter — not 24VLine
  • VALVE24V to the single solenoid24V
  • FLAMEµA DC on the rod. Not a 24V circuit24V

PSC blower + run cap

Heat / cool / park taps on the motor. The cap is on this blower — not the outdoor dual can.

  • HEATHeat speed tap24V
  • COOLCool speed tap24V
  • PARKUnused leads parked24V
  • CAPRun capacitor on the blowerCap

Landing

  • LineL1IFCinducer

    120 VAC after W

  • 24VIFCPSIFC

    ~24 VAC prove. Open PS = no ignition.

  • LineIFCHSI

    120 VAC during trial

  • 24VIFCgas valve

    ~24 VAC after flame prove starts

  • 24VFlame rodIFC

    µA DC. Not 24V.

  • LineIFCblower

    120V tap + cap

Prove it

  • 24 VAC from R to C at the IFC. Fuse / transformer first if the stat is dark.
  • W at the IFC under a heat call. Then inducer / igniter / valve per THIS door card.

Do not

  • Do not land a ComfortBridge 1/2 or Infinity ABCD pair on this IFC.
  • Do not hunt W2 / E8 / high-fire on a one-stage door.
  • TWIN must be empty on a standalone.

9-speed tap, PSC, and CT motors share this thermostat landing. The motor is on the IFC harness diagram.

Sequence

  1. 1

    W

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

Faults on this IFC

Step 1, then 2, then 3. Expected reading and the fail branch sit under each check.

13 / 33

Limit

warn

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

  1. 1 Treat this as flame outside the exchanger

    Do not reset the Bryant 916S rollout and walk away. Write the code, kill the call, and look for flame at the burners, crossover, and vestibule before you do anything else.

    Expect: No flame outside the exchanger. Burners seated. Crossover lit.

    If pass: Still inspect secondary / flue / condensate before you reset.

  2. 2 Secondary, condensate, and flue

    Blocked secondary, drowned collector, or a plugged flue pushes flame out the front. Pull the inducer/collector look, confirm the trap is flowing, and check PVC/vent. Heat-speed tap / 18-speed setup, filter, coil. 915SB 33 is the same winter call as Carrier 59SC5.

    Expect: Dry collector, open flue, trap clear.

  3. 3 Reset only after the cause is fixed

    Manual-reset rollout. Recurring rollout on Bryant 916S is a CO / fire call — cracked primary, misaligned burners, or a failed secondary. Confirm CO in the space before you leave.

    Expect: One clean cycle after the cause is fixed. No second reset as a repair.

14 / 34

Ignition

lockout

No flame prove.

  1. 1 Watch one full try — do not reset

    Write the Bryant 916S code. Watch inducer, HSI glow, valve click, flame, µA. The step that dies is the repair. Resetting only burns another try into a harder lockout. HSI, gas, rod, ground. 34 then 13-style lockout 14.

    Expect: W

  2. 2 Gas and the valve

    Cock open, inlet pressure, then manifold on the stage that is failing vs the rating plate. 24 VAC at the valve during trial? Coil ohms? A valve that never opens looks like a ‘bad igniter’ if you did not watch the sequence.

    Expect: Inlet and manifold on the plate. 24 VAC only during trial.

  3. 3 Flame prove, then the lockout timer

    Glow + valve + no prove → rod, ground, or IFC sense. Prove then drop → µA / PS / limit. Soft lockouts on this family often auto-reset on a long clock — do not sit on resets.

    Expect: Stable µA after light-off. No new PS/limit code.

24

Fuse

warn

24 V fuse.

  1. 1 Find the 24 V short before you replace the fuse

    On Bryant 916S an open IFC fuse is a short on W, Y, G, HUM, EAC, or a data pair landed on 24 V. Unplug the thermostat / data harness first. Tstat short, HUM, valve harness.

    Expect: Fuse out. 24 V transformer still good. Harness isolated.

  2. 2 Replace the fuse with the harness off

    New fuse, harness still off. If it holds, the short is in the field wiring or accessory. Plug one circuit back at a time (W, then Y, then HUM/EAC).

    Expect: Fuse holds with harness off. Dies when the shorted lead lands.

  3. 3 If it blows with the harness off

    Short is on the Bryant 916S IFC or the gas-valve harness. Unplug the valve and try once more. Repeat blow with valve unplugged = IFC.

    Expect: Do not keep feeding fuses into a welded valve coil or a burned IFC trace.

31

PS / draft

lockout

The only switch did not close.

  1. 1 Prove inducer and the live code

    Do not pull power — that clears the Bryant 916S active code. Write 31. Is the inducer spinning on this call? Silent inducer is not a pressure switch. Trap, collector, PVC, wind, inducer. 912S still has a 92% collector — not a chimney.

    Expect: 120 VAC at the inducer on a heat call. Wheel turning.

    If fail: 120 VAC missing → IFC / door switch / incoming power. Voltage + dead motor → inducer.

    If pass: Inducer running + this code → trap, hose, switch, vent (step 2).

  2. 2 Trap, collector, and the hose

    A drowned 96% trap will not make collector pressure. Pull the trap, flush it, confirm the collector box and inducer outlet are not full. Hose cracked, off the port, or full of water fakes an open switch.

    Expect: Trap flowing, hose dry and downhill, ports not swapped on a two-switch board.

  3. 3 Switch ohms, then vent load

    Ohm the pressure switch: NO, must close when that inducer speed is making the collector setpoint. If the switch is good, walk the PVC — bird screen, ice, long 2" run, wind, shared chase.

    Expect: Single PS: One NO switch. Closed only with inducer up.

    If fail: Replace the open switch only after the vent and trap are proven.

    If pass: Switch closes on draft and the code stays → IFC input.

Workflows

33 on a 915S / 916S

Heat works, then drops. Classic Legacy callback.

  1. 1 Prove the call and the live code

    This blower is not 926T VS model-plug CFM. Read the heat tap / 18-speed setting.

    Expect: Write whatever Legacy / Comfort two-digit IFC is showing. Write the two digits before power is pulled. 11 = no history.

    If fail: No call at the IFC → stat / harness. Do not change gas parts.

  2. 2 Isolate the first failed step in the sequence

    Filter and the A-coil. Legacy jobs often got a thick media cabinet.

    Expect: The first dead output or open prove.

  3. 3 Confirm with a number, then the next part

    If rollout is the open part of the 33 circuit, stop and inspect. Do not keep resetting.

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

    If fail: Stay on this plate. The out-of-range reading is the part.

    If pass: Reading in range → the next step in this workflow is the repair.

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

Install this plate

Install 916S / 915S / 912S as Legacy Comfort 96 single-stage. One PS, two-digit 31/33/34.

Cat IV PVC · single-stage · one PS · multi-speed / VS per exact 91xS plate · 24V W

IFC

  • Carrier-platform two-digit: 31 draft, 33 limit, 34 ignition. Same language as 59SC5.
  • One pressure switch. 32-as-low-fire does not exist on this plate.
  • Blower is plate-specific (916S vs 915S vs 912S). Read the motor and the setup SW on THIS door.

First fire

  1. 1W: 31 must close, then 34-path ignition, then heat speed / CFM.
  2. 2Cap W2. This is not 926T.

Do not on Bryant 916S

  • Do not apply 926T model-plug / 32 commissioning.
  • Do not treat 800S 31 as the same vent (that 31 is metal Cat I).

Maker literature

FieldBench does not host manufacturer files. Each link opens the maker’s own literature page in a new tab.

Warranty and bulletins

Affected models, serial range, symptom, remedy, date. Maker files open on the manufacturer site.

All bulletins

  • Residential limited warranty

    warranty sheet

    Carrier / Bryant registered heat-exchanger terms

    Current 59-series / Evolution / Preferred registered warranty · Limited warranty certificate

    Open factsOpen manufacturer PDF

  • Dealer portals

    dealer

    Where remaining service letters live

    Current-year service letters not on a public literature page · Maker dealer portal

    Open factsOpen manufacturer PDF