FieldBench
Models
Carrierheat pump

25VNA4

Infinity Greenspeed inverter HP

Infinity inverter heat pump. Outdoor drive + ABCD. Faults are inverter/comm/sensor, not a contactor-and-cap story. Do not charge it like a 24ACC6 piston unit and do not look for L-codes on a Comfort single-stage.

Not 24VNA6 / 24VNA9 (AC-only inverter — no RV, no defrost). Not 25HBC / 24ACC6 / 24ABB3 / 24ACC4 single-stage (contactor, dual cap, piston/TXV). Not Performance 24TPA. A 24ACC6 has no inverter L-codes and no ABCD drive.

Diagnose this modelInstall notesBoard cross-refField wiring

Drive

Inverter scroll · variable capacity

Bus

Infinity ABCD to the wall control and indoor

Charge

Weigh-in + line-set. Superheat is not a 410A piston chart.

Sister

Bryant 280ANV · 24VNA6 AC-only inverter cousin

This board

Outdoor inverter + Infinity UI

  • Infinity thermostat events first — English text on the wall control.
  • Outdoor board / inverter LED for drive faults (overcurrent, discharge, comm). L5/L4-class on the drive, not a Comfort contactor chatter.
  • No conventional Y1/Y2 staging — capacity is serial. There is no outdoor contactor to listen for.
  • Do not apply a 24ACC6 dual-cap / SH-SC playbook as the first move.

Infinity last 10. Outdoor inverter last-fault if the stat is blank.

Universal swap

No universal

Inverter outdoor. No furnace IFC universal.

White-Rodgers

—

ICM

—

Honeywell

—
  • Indoor furnace universals (50A55, 50M56U, ICM282B, ICM2811). This is not an IFC.
  • Do not ‘adapt’ a furnace board to an outdoor inverter or defrost PCB.

After you pull the dead card

  1. 1OEM Greenspeed outdoor control. 280ANV is the Bryant twin.

Field wiring

Written landings for Carrier 25VNA4. Not a factory schematic.

Infinity / Evolution inverter HP
ABCD + RV / defrost on the driveR-410A

25VNA4 / 280ANV. Same ABCD as 24VNA6 — plus a reversing valve and defrost on the outdoor drive.

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

This indoor

Infinity indoor on ABCD. This outdoor has the RV.

ABCD heat pump

Infinity / Evolution HP outdoor.

Infinity / Evolution wall control

Four-wire ABCD. D is 24V hot, not Y.

  • ADataData
  • BDataData
  • C24V common24V
  • D24V hot — not a cool call24V

Infinity / Evolution indoor

Same ABCD. Indoor CFM is serial. A Comfort 59SC5 does not belong here.

  • ADataData
  • BDataData
  • C24V common24V
  • D24V hot24V

Outdoor communicating drive

ABCD (or the outdoor comm harness). No Y contactor. No dual cap.

  • ADataData
  • BDataData
  • C24V common24V
  • D24V hot — still not Y24V

Outdoor line — inverter drive

208/230 into the drive. No contactor slam. DC bus can stay live after the disconnect.

  • L1Line to the driveLine
  • L2Line to the driveLine
  • GNDEquipment groundLine

Landing

  • DataABCD throughout

    Data + 24V C/D. No O/B stat wire on most of these.

  • 24VRV and defrost

    On the outdoor drive. Not a furnace function.

Prove it

  • Same ABCD prove as 24VNA6, then confirm this plate is the HP (RV + outdoor coil sensor).

Do not

  • Do not use this on 24VNA6 / 191VAN. Those have no RV.
  • Do not charge it like a 24ACC6 piston unit.

Included so the HP twin is not silently reused as the AC diagram.

Sequence

  1. 1

    Call

    Wall control requests capacity over ABCD. Indoor IFC (59MN7 family typical) sets CFM. Outdoor inverter ramps. No Y contactor pull-in.

  2. 2

    Defrost

    Inverter + IFC coordinate. A failed outdoor coil sensor looks like ‘always iced’ or ‘never defrosts.’

  3. 3

    Protect

    HPS/LPS still trip the drive. Charge mistakes show up here — you do not ‘top off’ a Greenspeed.

Faults on this IFC

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

Comm

ABCD / outdoor drop

lockout

Drive or bus. Wall control loses the outdoor.

  1. 1 Let it cool, then read the drive LED

    On Carrier 25VNA4 overcurrent / overheat is often a dirty coil, a failed OD fan, or a locked compressor — not a dead inverter. Clear airflow, confirm the OD fan, and read the drive LED before you order a control. ABCD landing and polarity, outdoor board power, inverter comms harness.

    Expect: OD fan running. Coil clean. Drive LED decoded from THIS outdoor’s card.

  2. 2 Voltage and compressor windings

    Incoming voltage in range (this plate’s line-voltage code). Compressor windings even, no ground. A shorted compressor will kill a new drive. C still required at the wall control.

    Expect: Balanced windings. No winding to ground. Line voltage stable under load.

  3. 3 Charge and the drive last

    A starved or flooded compressor will overcurrent. Confirm SH/SC and charge weight. Only then condemn the inverter. Indoor must be Infinity-capable. A 24ACC6-style indoor pairing is the wrong mental model.

    Expect: Charge on the nameplate. Drive code gone after a cool-down and a clean coil.

HPS / LPS

Pressure protection

lockout

Still real on an inverter.

  1. 1 Let it cool, then read the drive LED

    On Carrier 25VNA4 overcurrent / overheat is often a dirty coil, a failed OD fan, or a locked compressor — not a dead inverter. Clear airflow, confirm the OD fan, and read the drive LED before you order a control. Coil, fan, charge by weigh-in — you do not ‘top off’ a Greenspeed.

    Expect: OD fan running. Coil clean. Drive LED decoded from THIS outdoor’s card.

  2. 2 Voltage and compressor windings

    Incoming voltage in range (this plate’s line-voltage code). Compressor windings even, no ground. A shorted compressor will kill a new drive. Outdoor fan that is actually the inverter-driven fan, not a dual-cap PSC motor.

    Expect: Balanced windings. No winding to ground. Line voltage stable under load.

  3. 3 Charge and the drive last

    A starved or flooded compressor will overcurrent. Confirm SH/SC and charge weight. Only then condemn the inverter. Do not use 24ACC6 piston superheat as the pass/fail.

    Expect: Charge on the nameplate. Drive code gone after a cool-down and a clean coil.

Inverter

Drive overcurrent / overheat

lockout

L5/L4-class faults on the drive.

  1. 1 Let it cool, then read the drive LED

    On Carrier 25VNA4 overcurrent / overheat is often a dirty coil, a failed OD fan, or a locked compressor — not a dead inverter. Clear airflow, confirm the OD fan, and read the drive LED before you order a control. Compressor to ground, heat sink, supply voltage. Weigh-in vs nameplate.

    Expect: OD fan running. Coil clean. Drive LED decoded from THIS outdoor’s card.

  2. 2 Voltage and compressor windings

    Incoming voltage in range (this plate’s line-voltage code). Compressor windings even, no ground. A shorted compressor will kill a new drive. These L-codes do not exist on 24ACC6. If you are looking at a contactor, you are on the wrong outdoor.

    Expect: Balanced windings. No winding to ground. Line voltage stable under load.

  3. 3 Charge and the drive last

    A starved or flooded compressor will overcurrent. Confirm SH/SC and charge weight. Only then condemn the inverter.

    Expect: Charge on the nameplate. Drive code gone after a cool-down and a clean coil.

Workflows

No cool, Infinity HP

Fan indoor, outdoor silent.

  1. 1 Prove the call and the live code

    Stat event list. If it is a bus fault, do not gauge up yet.

    Expect: Write whatever Outdoor inverter + Infinity UI is showing. Infinity last 10. Outdoor inverter last-fault if the stat is blank.

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

  2. 2 Isolate the first failed step in the sequence

    Outdoor powered? Inverter LEDs? There is no contactor chatter to chase — if you hear a contactor, it is not this unit (see 24ACC6).

    Expect: Defrost: Inverter + IFC coordinate. A failed outdoor coil sensor looks like ‘always iced’ or ‘never defrosts.’

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

    Charge is weigh-in plus line-set. Superheat on a variable drive is not a 410A piston chart and not a 24ACC6 TXV subcooling-only shortcut. Pair indoor must be Infinity (FE/FV/59MN7 family). A 59TP6 can sit on the same job only if the control scheme was designed for it — most were not. Do not replace a dual run cap that is not there.

    Expect: Charge: Recover and weigh. Nameplate + ounces/ft. Not piston SH. · ABCD: Communicating to the Infinity indoor / 59MN7 family. D is not Y.

    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.

Greenspeed vs Comfort 24ACC

Invoice just says Carrier heat pump.

  1. 1 Prove the call and the live code

    Inverter drive + ABCD = 25VNA / Greenspeed (this page). Contactor + dual run cap + piston/TXV = 24ACC6.

    Expect: Write whatever Outdoor inverter + Infinity UI is showing. Infinity last 10. Outdoor inverter last-fault if the stat is blank.

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

  2. 2 Isolate the first failed step in the sequence

    No inverter L-codes on a 24ACC. No weigh-in-only-as-the-only-method on a piston 24ACC.

    Expect: Defrost: Inverter + IFC coordinate. A failed outdoor coil sensor looks like ‘always iced’ or ‘never defrosts.’

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

    Wrong charge method is how these get overcharged after a 24ACC tech treats them like a Comfort 13 SEER.

    Expect: Charge: Recover and weigh. Nameplate + ounces/ft. Not piston SH. · ABCD: Communicating to the Infinity indoor / 59MN7 family. D is not Y.

    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

Charge

Recover and weigh. Nameplate + ounces/ft. Not piston SH.

ABCD

Communicating to the Infinity indoor / 59MN7 family. D is not Y.

Drive

Inverter LEDs / last fault. No contactor coil 24 VAC test.

Gotchas

  • Bryant 280ANV is the badge twin. 24VNA6 is the AC-only inverter cousin.
  • 24ACC6 is the Comfort single-stage cousin in name only — different everything.
  • 59MN7 is the indoor that belongs on this bus. 59SC5 / 24V Comfort pairing is not Greenspeed.

Related plates

Install this plate

Install 25VNA4 as Infinity Greenspeed. Weigh-in inverter on ABCD. Twin of Bryant 280ANV.

Inverter HP · Infinity ABCD · weigh-in · no contactor / no dual cap

Pair & charge

  • ABCD to 59MN7 (typical) and the Infinity wall control.
  • Weigh-in + line-set adder from the 25VNA4 I/O. Not 24ACC6 piston/TXV charging.

First fire

  1. 1Bus pair first. Cool then heat. Outdoor drive faults live here.

Do not on Carrier 25VNA4

  • Do not apply 24ACC6 cap / contactor steps.
  • Do not pair to a 59TP6 24V indoor as if it were Infinity.

Maker literature

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

  • 25VNA4 product pageProduct pageInfinity Greenspeed inverter HP.Open manufacturer PDF
  • Carrier HVAC resourcesLiterature searchOwner-facing literature hub. Do not invent a 59-series I/O URL.Open manufacturer PDF
  • Carrier residential furnacesLiterature searchSearch Carrier 25VNA4 on the maker’s literature page.Open manufacturer PDF

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