FieldBench
Wiring

iComfort furnace

I+ / I−

I+ / I−

SLP99V / SL297NV / EL296V communicating. iComfort S30/S40 on I+ and I−. Many EL296V jobs are still 24V — use that landing if RS wires are empty.

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 → IFC120V
  2. 2Call. Data pair or 24V W → IFCBus or 24V
  3. 3Draft. IFC → inducer → proveTwo-stage PS or a pressure band
  4. 4Ignite. IFC → HSI → valve120V igniter
  5. 5Blow. IFC → serial ECMNo tap, no cap

iComfort communicating

S30/S40 and a communicating outdoor, or communicating indoor-only.

iComfort S30 / S40

R, C, I+, I−.

  • R24V hot24V
  • CCommon24V
  • I+DataData
  • I−DataData

iComfort IFC

E105 on a 24V-only job means data wires landed on RS terminals. Pull them.

  • I+DataData
  • I−DataData
  • R24V24V
  • CCommon24V
  • W124V heat if used24V

Landing

  • DataStat I+/I−IFC I+/I−outdoor

    iComfort data

  • 24VR and C at the stat

    ~24 VAC

EL296V as 24V

No iComfort outdoor. Conventional W1/W2/Y. Leave I+ / I− empty.

Two-stage 24V stat

Normal W1/W2/Y/G. RS / I+ unused.

  • RHot24V
  • CCommon24V
  • W1Low fire24V
  • W2High fire24V
  • YCool24V
  • GFan24V

Landing

  • 24VStat W1/W2IFC W1/W2

    Two-stage heat

  • 24VStat YIFC Youtdoor Y

    Cool

IFC harness — communicating two-stage

Call arrives on the data pair (or 24V W). Gas train is still inducer / prove / igniter / valve.

Transformer + fuse

24V still exists for accessories and for a 24V outdoor. Data pair is not the transformer.

  • L1 / N120VLine
  • R / C24V strip24V
  • FUSEOn the IFC24V

24V safety chain

Limit / rollout / door still open the heat path. Codes are on THIS IFC language.

  • DOORInterlock24V
  • LIMITMain limit24V
  • ROLLOUTManual reset24V

Two-speed inducer + dual PS

Low vs high prove. Do not tee the hoses. Do not apply this to a modulating cousin.

  • IND LO/HITwo-speed inducerLine
  • LPSLow prove24V
  • HPSHigh prove24V

HSI + two-stage valve

Two solenoids or a two-stage valve. Staging is the bus or W1/W2, not a tap.

  • HSI120V igniterLine
  • MV / HV24V low / high solenoids24V
  • FLAMEµA DC24V

Serial variable-speed ECM

IFC talks to the motor on the serial harness. No F-taps. No dual run cap on this blower.

  • SERIALIFC-to-motor harness. Unplugged motor = CFM / comm fault, not a tap problem24V
  • CFMSet in the IFC menu / model plug / CoolCloud — not a dip switch on most of these24V

Landing

  • LineCallIFCinducerprove

    Low then high

  • LineIFCHSIvalve

    120V igniter, 24V or serial valve

  • 24VFlame rodIFC

    µA DC

  • DataIFCserial blower

    No F-taps. No PSC cap.

Prove it

  • If the stat is S30, I+/I− must be landed and the furnace must be on the equipment list.
  • E105 with a 24V stat = data wires on the RS terminals.

Do not

  • Do not land Y on I+.
  • ML196 / EL196E / EL296E are 24V unless the silk actually has iComfort.

I+ / I− are the published iComfort terminals.

Plates on this landing