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Appliance Error Codes Database

Found 168 verified diagnostic error codes

All Categories ductless-mini-split — Daikin 15 and 19 Series furnace — York YP9C modulating condensing gas furnaces documented in the York installation manual controls-thermostats — ATW-RTU room thermostats paired with ATW-IOT-01 on Yutaki systems ductless-mini-split — Gree residential mini-splits that publish E5 in the protection code family controls-thermostats — Bryant Evolution communicating systems using the Evolution Connex control and a four-conductor communication bus controls-thermostats — Google Nest Learning Thermostat and Nest Thermostat furnace — York Affinity YP9C modulating condensing furnaces and the TP9C, CP9C and LP9C models sharing the same installation manual boiler — Baxi and Potterton domestic boilers that display E119 controls-thermostats — Google Nest thermostats covered by the E-code power guide controls-thermostats — Google Nest learning and programmable thermostats that report power and delay conditions on screen ductless-mini-split — Mitsubishi Electric indoor units publishing the P-series fault table, including M-Series wall units and Mr Slim indoor equipment heat-pump — XP17 heat pumps with iComfort communicating controls ductless-mini-split — MRCOOL DIY mini-split generations that report an inverter compressor drive fault ductless-mini-split — Panasonic wall-mounted split systems that report H-series and F-series self-diagnosis codes heat-pump — Altherma 3 R MT with ELBH-E or ELBX-E and ERRA08-12 furnace — Rheem residential gas furnaces covered by the published technical FAQ furnace — R96V communicating condensing gas furnaces ductless-mini-split — Daikin indoor units covered by the SM-TS3 malfunction chart, including room air, SkyAir, and VRV indoor equipment ductless-mini-split — WindFree 3.0 AR C ductless-mini-split — Bosch Climate 5000 ductless mini-split systems documented in the Bosch service and manual library ductless-mini-split — BMKH floor-ceiling indoor units ductless-mini-split — Midea wall-split systems, and systems built on the same platform sold under other names, that publish E2 furnace — Goodman GMVC-series two-stage variable-speed gas furnaces documented in the installation and operating instructions boiler — Vaillant ecoTEC gas boilers covered by the Vaillant United Kingdom fault code list ductless-mini-split — Diamante and Quantum systems in the manufacturer code list ductless-mini-split — Mitsubishi Electric indoor units that publish the P-series protection table, including Mr Slim cassette, ducted, and ceiling-suspended indoor units heat-pump — LG residential air conditioners covered by the United States help-library article grouping these codes as outdoor compressor or circuit board problems ductless-mini-split — Daikin indoor units covered by the SM-TS3 malfunction code chart, spanning room air, SkyAir, and VRV indoor equipment multi-zone — LG multi-split systems where several indoor units share a single outdoor unit, as described in LG help-library guidance ductless-mini-split — LG single-zone systems in MFL41161610 ductless-mini-split — Senville LETO Series ductless-mini-split — Diamante Essenza, Diamante Pro, Quantum Fresh, Hyperformance, and Ultra heat-pump — Stiebel Eltron WPL air source heat pumps commissioned through the manufacturer parameter set ductless-mini-split — Hisense residential split air conditioners documented in the Hisense service and document library boiler — Vaillant ecoTEC gas boilers covered by the published United Kingdom fault code list ductless-mini-split — Midea residential split air conditioners covered by the Midea online troubleshooting code reference heat-pump — Gree residential inverter systems covered by the OEM guide furnace — Carrier deluxe two-stage gas-fired induced-combustion furnaces with PSC or ICM blower motors, per troubleshooting guide 58-3T ductless-mini-split — Della ductless mini-split systems documented in the Della manual and support library Dishwasher LaserJet Printer ductless-mini-split — Mr Slim families covered by Mitsubishi Electric's P8 reference ductless-mini-split — Multi21+ and documented residential mini-splits ductless-mini-split — Daikin multi-split systems and splits that publish UF for a wiring and piping combination fault boiler — Ideal Logic and Vogue gas boilers using the F-series and L-series fault codes published by Ideal Heating ductless-mini-split — Daikin split and multi-split systems that publish UA for an indoor and outdoor combination fault ductless-mini-split — MRCOOL DIY ductless systems across the third, fourth, and fifth generations documented in MRCOOL support air-handler — Goodman and Amana variable-speed air handlers with an integrated control module reporting motor codes on a seven-segment display and through a ComfortNet thermostat controls-thermostats — ecobee smart thermostats with installer settings governing staging, thresholds, and equipment lockouts controls-thermostats — Drayton Wiser multi-zone heating systems using a heat hub with room thermostats and smart radiator thermostats ductless-mini-split — MRCOOL single-zone and multi-zone families in official support ductless-mini-split — Gree residential mini-split indoor units using the F-series sensing bulb codes described in Gree North America support boiler — Ideal Logic, Logic Max, and Logic Plus boilers that display F1 Air Conditioner heat-pump — Mitsubishi Electric outdoor units publishing the U-series fault table, including M-Series and MXZ multi-zone outdoor equipment boiler — Ideal Logic and Logic Max boilers covered by the published fault code guidance ductless-mini-split — Econo IF, Vario TL, and Optima TP single zone, and the multi-zone systems sharing the table ductless-mini-split — Daikin room air conditioner splits and multi-split systems that publish U0 in the malfunction code table controls-thermostats — tado Smart Radiator Thermostat V3+ and earlier devices in the cited support flow ductless-mini-split — Panasonic room air conditioners with the self-diagnosis function described in Panasonic service documentation ductless-mini-split — LG single-zone systems in general service manual MFL41161610 ductless-mini-split — Sophia multi-zone cassette indoor units furnace — GMVC80 condensing gas furnaces boiler — Ariston Clas gas boilers whose fault codes are grouped by leading digit in the Ariston user documentation furnace — Carrier two-stage and variable-speed modulating condensing furnaces that report status code 31 furnace — Goodman and Amana gas furnaces with an integrated ignition control that flashes seven for low flame signal furnace — Affinity YP9C modulating gas furnaces boiler — Viessmann Vitodens gas condensing boilers whose displayed fault codes are listed in the Viessmann fault checker ductless-mini-split — Mitsubishi Electric indoor units that publish the P-series fault table, covering Mr Slim and M-Series indoor equipment ducted-split — Carrier Infinity System Control paired with communicating equipment, with the outdoor-unit code structure documented for 24VNA6 and 25VNA4 variable-speed units heat-pump — Midea residential split air conditioners and heat pumps covered by the Midea online troubleshooting code reference ductless-mini-split — LG residential air conditioners covered by the United States help-library article that groups these codes as sensor problems boiler — Greenstar Si Compact ErP furnace — Ruud gas furnaces whose integrated controls report diagnostics through a blinking indicator, including the R96T range furnace — R96T two-stage communicating condensing furnaces controls-thermostats — Lennox iComfort communicating thermostats and the equipment controls they are paired with boiler — Worcester Bosch Greenstar boilers that pair E9 with cause code 219 ductless-mini-split — Samsung indoor air conditioner units whose display shows the reminder and operating-mode characters described in Samsung support ductless-mini-split — Econo, Vario, Optima, Motto, and Umbra mini-splits heat-pump — Hitachi Yutaki air-to-water heat pump systems documented in the Hitachi air-to-water installation and operation manuals heat-pump — NIBE air source and ground source heat pumps with controllers that store an alarm log and operating history boiler — Current ecoTEC plus boilers covered by manual 0020308121-04 ductless-mini-split — Pioneer Diamante and Quantum ductless systems whose code lists are published in Pioneer support ductless-mini-split — Panasonic reverse-cycle wall split systems that report F11 in the self-diagnosis table air-handler — Trane air handlers and indoor coils fitted with a condensate overflow switch, as described in Trane homeowner support boiler — Ariston Clas ONE, Clas System ONE, and Alteas ONE boilers showing 108 ductless-mini-split — KSIV Series ductless-mini-split — Senville ductless mini-split systems across the Aura, Leto, and earlier series documented in Senville support ductless-mini-split — Toshiba residential and light-commercial systems fitted with a wired remote controller controls-thermostats — Rheem and Ruud EcoNet communicating systems in which a smart thermostat or control center shares a four-wire network with indoor and outdoor equipment boiler — Logic Max Combi boilers in manual 237660 A01 ductless-mini-split — GE Zoneline packaged terminal air conditioners and heat pumps documented in GE Appliances owner and support material ductless-mini-split — Mitsubishi Heavy Industries room air conditioners documented in the MHI user manual library controls-thermostats — tado Smart Radiator Thermostat furnace — Trane gas furnaces whose integrated control proves flame by rectification, as described in Trane homeowner support for a burner that shuts off after ignition ductless-mini-split — Fujitsu General residential indoor units that report faults through operation and timer indicator lamps heat-pump — Yutaki hydronic heat-pump systems ductless-mini-split — Klimaire ductless mini-split systems documented in the Klimaire service and support library heat-pump — F2120 air-to-water heat pumps heat-pump — Daikin outdoor units covered by the SM-TS3 malfunction chart, including room air, SkyAir, and VRV outdoor equipment Washing Machine furnace — York YP9C, TP9C, CP9C, and LP9C furnaces covered by the cited manual ductless-mini-split — Mitsubishi Electric Mr Slim and M-Series systems that publish the P-series protection table multi-zone — LG multi-split systems where several indoor units share one outdoor unit controls-thermostats — tado smart thermostat systems using a wireless receiver or an extension kit between the control and the heating appliance ductless-mini-split — TCL residential split air conditioners documented in the TCL product download library ductless-mini-split — Hi-Ultra Xtreme R-454B furnace — Carrier deluxe two-stage gas-fired induced-combustion furnaces with PSC or ICM blower motors, as covered by troubleshooting guide 58-3T heat-pump — Daikin outdoor equipment covered by the SM-TS3 malfunction chart, spanning room air, SkyAir, and VRV outdoor units ductless-mini-split — Mitsubishi Electric M-Series and Mr Slim systems that publish the E-series communication table ductless-mini-split — Forward Series systems in the manufacturer service manual boiler — Clas One and Clas System One condensing gas boilers ductless-mini-split — Climate 5000 Generation 3 R-454B multi-zone ductless-mini-split — KSIO series systems in the manufacturer troubleshooting manual furnace — Goodman and Amana single-stage and two-stage gas furnaces with an integrated ignition control boiler — Vaillant ecoTEC plus and ecoTEC sustain boilers that list F.22 ductless-mini-split — Daikin indoor units covered by the SM-TS3 malfunction chart, where the C division covers sensor systems furnace — Rheem R96V modulating condensing gas furnaces documented in the Rheem service literature ductless-mini-split — Senville systems covered by the manufacturer EC 51 support article ductless-mini-split — Cooper and Hunter ductless mini-split systems documented in the Cooper and Hunter support library furnace — S9V2 S-Series two-stage condensing gas furnaces ductless-mini-split — Forward Series light-commercial — SkyAir RZR-P and RZQ-P(9) light-commercial — Amana PTAC models covered by the M70 service procedure ductless-mini-split — MRCOOL mini-splits covered by official P0/PC00 support furnace — Carrier 58MCB Series 110 and 120 condensing gas furnaces ductless-mini-split — LETO and AURA models using an applicable AC fan motor boiler — Baxi domestic gas boilers using the E-series fault codes listed in Baxi support material ductless-mini-split — MRCOOL generations and models identified in official support furnace — Goodman GMVC80 condensing gas furnaces heat-pump — Grant Aerona air source heat pumps documented in the Grant fault and support material heat-pump — Ecodan FTC5 cylinder units, EHPT20X-MHCW and EHST20(D)(C)-MHCW boiler — Vitodens 100-W heat-only boilers in the cited UK installation instructions multi-zone — Climate 5000 Generation 3 R-454B multi-zone outdoor units heat-pump — Trane TruComfort variable-speed outdoor units on ComfortLink II communicating controls, including the XV20i heat pump ductless-mini-split — Amana packaged terminal air conditioners and heat pumps covered by the Amana PTAC service literature controls-thermostats — Honeywell Home T6 programmable thermostats configured through installer setup parameters controls-thermostats — Lennox communicating systems on iComfort S30, E30 and compatible displays, covering furnaces, air handlers, outdoor units, equipment interface modules and iHarmony zoning heat-pump — Daikin equipment covered by the SM-TS3 malfunction chart, where the U division reports system-level conditions across room air, SkyAir, and VRV furnace — Goodman GMVC-series and related integrated furnace controls documented in the installation and operating instructions heat-pump — Mitsubishi Electric inverter outdoor units publishing the U-series fault table, including M-Series single-zone and MXZ multi-zone equipment controls-thermostats — Hive heating control systems using a hub, a thermostat, and a boiler receiver as described in Hive support multi-zone — Multi21+ and the residential ranges in the Gree code overview ductless-mini-split — Discontinued Quantum WYS, CYB, RYB, UYB, and FYB heat-pump — Daikin Altherma air-to-water heat pump systems serving space heating and a domestic hot water cylinder furnace — American Standard gas furnaces whose integrated controls retain a stored fault history alongside the current status boiler — Baxi domestic boilers covered by the manufacturer E133 guidance ductless-mini-split — Blueridge BMKH ductless mini-split systems documented in the Blueridge manual library ductless-mini-split — Aurora Xtreme Inverter 36,000 BTU cooling-only 220 V heat-pump — Aquarea air-to-water heat pumps ductless-mini-split — Samsung indoor air conditioner units that display the C1 group of service codes described in Samsung support material furnace — Carrier deluxe two-stage gas-fired induced-combustion furnaces with PSC or ICM blower motors, covered by troubleshooting guide 58-3T ductless-mini-split — Toshiba air conditioning equipment using the fault code tables published in the Toshiba United Kingdom technical handbook ductless-mini-split — Haier residential split air conditioners documented in the Haier service and resource library boiler — Worcester Bosch Greenstar gas boilers using the two-part display and fault code convention described in Worcester service instructions ductless-mini-split — Friedrich Floating Air ductless indoor units documented in the Friedrich product resource library
Flame sense fault ProfessionalRequired
Trane • furnace — Trane gas furnaces whose integrated control proves flame by rectification, as described in Trane homeowner support for a burner that shuts off after ignition

Trane furnace burner lights then shuts off: reading the flame sense fault

When a Trane furnace lights its burner and shuts down a few seconds later, the control has decided it cannot confirm the flame it just created. Trane treats that as a flame sensing condition. The burner did light, so the ignition side worked, and what failed was the proof step that keeps the gas valve open. Applies to: Trane gas furnaces whose integrated control proves flame by rectification, as described in Trane homeowner support for a burner that shuts off after ignition Trane support describes this behaviour for gas furnaces whose control proves flame by passing a small current through it. Trane also sells equipment where the same symptom has a different cause, and any numeric or flash code shown on your control is read from that model's own literature rather than from this description. Owner-safe checks: Listen to a complete heating call and note whether the burner lights at all, and how many seconds it stays alight. | Count how many calls succeed and how many fail over two or three days, including the time of day for each. | Replace a loaded filter with the specified clean one, since restricted airflow produces a different fault that can be confused with this one. Qualified technician: Measuring the flame signal in microamps, cleaning or repositioning a sensing electrode, and testing the ground path are licensed gas-furnace tasks. | Do not attempt to clean a sensing rod yourself. It sits in the burner compartment beside live components and a gas train, and an abrasive left on the surface makes the fault worse.

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184.07 / 184.08 ProfessionalRequired
Trane • heat-pump — Trane TruComfort variable-speed outdoor units on ComfortLink II communicating controls, including the XV20i heat pump

Trane XV20i alerts 184.07 and 184.08 in cold weather: why a working heat pump stays locked out

Both entries describe the state the outdoor control has entered, not a component it has condemned. Trane publishes its variable-speed alerts as a base code with a sub alarm, and the two lockout entries in that family behave differently from every protection alert underneath them. A protection alert shuts the compressor down for a cutout period and then releases itself. A lockout entry stops the system until power is cycled or the alerts are reset. In cold weather the alerts that accumulate underneath include one for which Trane names low outdoor ambient temperature, below a figure printed in its table, as a possible cause. Applies to: Trane TruComfort variable-speed outdoor units on ComfortLink II communicating controls, including the XV20i heat pump The alert architecture and the two lockout behaviours described here are read from Trane variable-speed outdoor unit Service Facts. Pressure thresholds, cutout times and the shutdown count that triggers the lockout are model specific and are printed in the Service Facts for the exact outdoor model, so treat those figures as something to look up rather than to carry across. Owner-safe checks: Photograph the alert screen and the alert history in order, with the display text beside each number. | Record the outdoor temperature and the time at each stoppage, because the protection alerts underneath are tied to operating conditions. | Check whether auxiliary or emergency heat is holding the house, which tells a technician what the system fell back to. Qualified technician: Charge assessment, pressure transducer checks and expansion valve diagnosis are qualified service work on a sealed refrigerant circuit. | Any inspection inside the outdoor cabinet on a variable-speed unit involves stored energy in the drive and belongs to a technician.

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P-series ProfessionalRequired
Toshiba • ductless-mini-split — Toshiba air conditioning equipment using the fault code tables published in the Toshiba United Kingdom technical handbook

Toshiba P-series protections: what the handbook groups under one letter

Toshiba organises its fault codes by leading letter, and the P-series marks protective shutdowns rather than component failures. A P code means the equipment measured a condition outside its permitted range and stopped itself, which is a materially different statement from an E code reporting a communication or controller problem. Applies to: Toshiba air conditioning equipment using the fault code tables published in the Toshiba United Kingdom technical handbook Toshiba's technical handbook covers a wide range of equipment sold in the United Kingdom, and the same code can appear against different subsystems on residential and on larger commercial equipment. Take the model from the outdoor and indoor data plates and read the code against the handbook table for that family. Owner-safe checks: Photograph the controller showing the complete code, including the letter and every digit that follows it. | Copy the indoor and outdoor model numbers from their data plates so the correct handbook table can be used. | Deal with the two airflow variables you can reach: wash the indoor filters and open up the space around the outdoor casing. Qualified technician: Refrigerant measurement, leak detection, and coil cleaning are certified activities under EPA Section 608 in the United States and F-Gas rules in the United Kingdom and European Union. | Repeatedly restarting a system that keeps reaching a protection puts the equipment back into the condition the protection stopped, which is worth avoiding.

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E01 / E02 / E03 ProfessionalRequired
Toshiba • ductless-mini-split — Toshiba residential and light-commercial systems fitted with a wired remote controller

Toshiba E01, E02, E03 error codes: wired controller communication

Toshiba uses E01, E02, and E03 for a communication break between the wired remote controller and the indoor unit. E01 is raised at the controller when it stops hearing the indoor unit, E02 is a controller transmission fault, and E03 is raised when the indoor unit receives nothing from the controller or network adaptor. Applies to: Toshiba residential and light-commercial systems fitted with a wired remote controller This applies to Toshiba systems with a wired wall controller that report the E0-series codes. Wireless-remote systems that signal faults by flashing indoor lamps use a different scheme, so confirm the installation has a wired controller before applying this page. Owner-safe checks: Record the exact code, E01, E02, or E03, whether the controller screen is blank or working, and whether the system was rewired or altered recently. | Check whether the indoor unit has power at its own supply, without opening any covers. Qualified technician: Checking the controller cable at the terminals, testing continuity, and swapping a controller or board to isolate the fault require a qualified technician.

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Indicator group ProfessionalRequired
TCL • ductless-mini-split — TCL residential split air conditioners documented in the TCL product download library

TCL indicators: telling a maintenance reminder from a real fault

TCL indoor units use the same indicator panel for maintenance reminders and for faults, which means the first question is always which kind of indication you are looking at. A filter reminder is cleared by the owner after cleaning; a fault indication is not, and trying to clear one as though it were the other wastes time. Applies to: TCL residential split air conditioners documented in the TCL product download library TCL publishes manuals per model in its download library rather than a single brand-wide code list, and indicator behaviour differs between ranges and generations. The manual for the model on your indoor unit is the reference for what each indication means and how it is cleared. Owner-safe checks: Establish first whether the unit still produces cooling or heating when asked, since that answers which kind of indication you are seeing. | Clean or replace the indoor filters following the manual, dry them fully before refitting, and then carry out the model-specific reset. | Photograph the indicator panel before any reset if operation has stopped, so the indication is preserved. Qualified technician: An indication accompanied by the unit refusing to operate is a fault report and needs a qualified technician rather than owner maintenance. | Do not open the indoor casing beyond the filter access the manual describes. Anything further sits alongside the board and the fan supply.

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Heat demand not delivered ProfessionalRequired
tado • controls-thermostats — tado smart thermostat systems using a wireless receiver or an extension kit between the control and the heating appliance

tado calling for heat with nothing happening: where the demand stops

When a tado control shows a heat demand and the appliance stays cold, the demand is stopping somewhere between the two. The chain runs from the thermostat, through the radio link, to a receiver or extension kit, and finally through a pair of contacts into the boiler, and each of those can fail while the one before it reports success. Applies to: tado smart thermostat systems using a wireless receiver or an extension kit between the control and the heating appliance tado has shipped several generations with different radio arrangements, including the newer tado X range which is not wired or paired like its predecessors. Match the product names on the devices you actually own to the tado support material for that generation before following any instruction. Owner-safe checks: Try to produce heat from the appliance or from any control other than tado, and note whether it works. | Look at the receiver or extension kit and note whether it shows any indication at all. | Write down anything that changed in the property recently, including furniture, appliances, routers, or a relocated thermostat. Qualified technician: Wiring between a receiver and a heating appliance carries mains voltage on United Kingdom installations, so terminal work belongs to a qualified person. | An appliance that produces no heat by any route is a heating fault and needs a Gas Safe registered engineer rather than control support.

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E2 / E4 ProfessionalRequired
tado • controls-thermostats — tado Smart Radiator Thermostat V3+ and earlier devices in the cited support flow

tado radiator E2 versus E4: no pin contact or too little valve travel

E2 means calibration found no contact between the thermostat motor and the radiator-valve pin. E4 means contact was found but the distance between the detected open and closed positions was too short. E2 starts with mount and adapter geometry; E4 starts with valve-pin travel and battery condition. Applies to: tado Smart Radiator Thermostat V3+ and earlier devices in the cited support flow These meanings apply to tado V3+ and earlier Smart Radiator Thermostats in the cited support article. Display symbols differ on the Basic model, and newer product generations require their own support path. Owner-safe checks: Identify the exact code, check the documented adapter and extender, use fresh approved batteries, and keep all work outside the wet valve body. Qualified technician: Leaking, seized, bent, corroded, or uncertain valve hardware and repeated calibration after correct mounting require heating or tado support.

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E1 ProfessionalRequired
tado • controls-thermostats — tado Smart Radiator Thermostat

tado Smart Radiator Thermostat E1 calibration error

tado defines Smart Radiator Thermostat E1 as calibration failure because the closed valve position was not detected. The support path focuses on secure mounting, the correct adapter, adequate batteries, and a valve pin that moves and returns properly. E2 and E4 are different calibration outcomes and should not be merged into E1. Applies to: tado Smart Radiator Thermostat This page follows tado's E1, E2, and E4 radiator-thermostat support article. Hardware generation, mounting bracket, adapter, and valve body vary, so use the instructions for the exact tado device. Owner-safe checks: Use the exact tado mounting guide, fit compatible fresh batteries, confirm the correct adapter and secure head, and never dismantle the water valve. Qualified technician: Leaking, bent, seized, damaged, or uncertain radiator valves, pressurised components, and recurring calibration after correct mounting need heating or tado support.

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Fault and parameter conditions ProfessionalRequired
Stiebel Eltron • heat-pump — Stiebel Eltron WPL air source heat pumps commissioned through the manufacturer parameter set

Stiebel Eltron WPL faults: commissioning parameters that look like breakdowns

A Stiebel Eltron WPL is commissioned rather than simply installed, and a large share of what owners report as faults are parameters doing exactly what they were set to do. Heating curves, bivalent points, and blocking times all change behaviour beyond recognition without anything being wrong with the machine. Applies to: Stiebel Eltron WPL air source heat pumps commissioned through the manufacturer parameter set WPL spans several generations with different controllers and different parameter names, and commissioning values are chosen for the building rather than supplied as defaults. The commissioning record for your installation matters as much as the manual, and an installer holds both. Owner-safe checks: Keep a simple record of when the system stops and starts over several days, noting the time rather than only the symptom. | Note the outdoor temperature and the indoor temperature achieved during the coldest weather you experience. | Ask whoever installed the system for the commissioning record, including the heating curve and the bivalent point. Qualified technician: Altering a heating curve or a bivalent point changes how a heat pump operates across its whole envelope, so the installer who commissioned it is the right person to adjust it. | Anything on the sealed refrigerant side of a WPL requires a certified handler under the F-Gas framework, and that boundary is unaffected by what the controller shows.

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Series-dependent codes ProfessionalRequired
Senville • ductless-mini-split — Senville ductless mini-split systems across the Aura, Leto, and earlier series documented in Senville support

Senville codes: the same characters mean different things by series

Senville publishes different code tables for its Aura, Leto, and earlier series, and the same two characters can describe unrelated conditions between them. The series therefore has to be established before the code is looked up, and the model prefix on the data plate is what establishes it. Applies to: Senville ductless mini-split systems across the Aura, Leto, and earlier series documented in Senville support Senville systems are identified by model prefix rather than by the name printed on the front panel, and the same series name has covered more than one generation. The support document that matches your exact model number is the reference, and a chart labelled only with the brand is not. Owner-safe checks: Photograph the data plates on the indoor and outdoor units and read the full model numbers from the images. | Photograph the displayed code before interrupting power for any reason. | Note whether the system fails at startup or after a period of running, since that alone separates two groups of conditions. Qualified technician: Testing the interconnecting cable, sensing elements, and boards requires casings that carry mains voltage to be opened, which is qualified work. | Conditions reached after a period of operation involve the refrigerant circuit on this equipment, and that is certified activity rather than an owner check.

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PC 0A ProfessionalRequired
Senville • ductless-mini-split — Senville LETO Series

Senville PC 0A: condenser high-temperature protection

Senville's LETO reference identifies PC 0A as condenser high-temperature protection, a protective shutdown that calls for airflow inspection before deeper refrigeration or control diagnosis. Applies to: Senville LETO Series This entry comes from the Senville LETO series code reference. Protection thresholds are set for a specific outdoor design, so a code that looks similar on another Senville series or another brand needs its own documentation rather than this definition. Owner-safe checks: With the system off, remove loose leaves or objects blocking the outdoor unit's clear airflow area. | Confirm the outdoor fan area is not visibly packed with debris without removing the grille or panels. Qualified technician: Coil deep-cleaning, fan diagnosis, refrigerant evaluation, sensor tests, and control checks require qualified service. | Keep the system off if the outdoor unit is hot, damaged, or repeatedly enters protection.

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EH 02 ProfessionalRequired
Senville • ductless-mini-split — LETO and AURA models using an applicable AC fan motor

Senville EH 02 error code: zero-crossing signal fault

Senville says EH 02 on applicable LETO and AURA equipment means the indoor PCB is not receiving the expected zero-crossing feedback associated with the AC fan motor; it does not apply the same way to DC-motor designs. Applies to: LETO and AURA models using an applicable AC fan motor This code is attached to a specific indoor fan motor design. Senville support scopes EH 02 to LETO and AURA models using the applicable AC fan motor, so a model built around a DC motor does not share the same signal arrangement and should not be diagnosed from this entry. Owner-safe checks: Confirm the exact series and whether the model uses the applicable AC fan motor before using this diagnosis. | Turn off system power completely, wait two minutes as Senville directs, and observe whether the code returns. Qualified technician: If the code remains, wiring, supply, fan design, and indoor PCB checks belong with qualified service. | Do not access the indoor electrical enclosure or test energized components.

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EC 51 ProfessionalRequired
Senville • ductless-mini-split — Senville systems covered by the manufacturer EC 51 support article

Senville EC 51: the board cannot read its own configuration

EC 51 means a main control chip is not receiving proper feedback from the EEPROM, the memory component holding the system's configuration data. It is a fault inside the electronics rather than a reading taken from the refrigerant circuit or the air path. Applies to: Senville systems covered by the manufacturer EC 51 support article This meaning follows the Senville support article for EC 51. Senville files codes by prefix, and EC codes on the equipment sit alongside EH, EL, and PC families that report different things, so match the exact characters and the prefix before using this page. Other manufacturers building on the same control platform publish their own version of the table. Owner-safe checks: Photograph the code exactly as displayed, including the space and both digits, and note which head showed it. | Carry out one complete power-off restart of two minutes and record whether the code returns and how quickly. | Note any recent electronics work, board replacement, or accessory fitting on the system. Qualified technician: Diagnosis of a configuration-memory fault requires the electrical compartment to be opened with the supply isolated, which is technician work. | Ask a technician to confirm the fault before any board is ordered, since the code narrows the fault to the electronics without selecting a board.

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CF / CI / dF ProfessionalRequired
Samsung • ductless-mini-split — Samsung indoor air conditioner units whose display shows the reminder and operating-mode characters described in Samsung support

Samsung CF, CI, and dF: three displays that are not faults at all

Samsung separates its indoor display characters into ones that need no service and ones that do. CF is a filter cleaning reminder, CI is the auto clean function running after the unit is switched off, and dF is the defrost operation during heating. Samsung states that the defrost display is not a product defect but one of the modes used to protect the outdoor unit. Applies to: Samsung indoor air conditioner units whose display shows the reminder and operating-mode characters described in Samsung support These three displays come from Samsung support material for indoor air conditioner units. Samsung markets equipment across many regions and display conventions differ between generations, so an older or a commercial Samsung indoor unit may not use the same characters. Check the manual supplied with the indoor unit before assuming a display is benign. Owner-safe checks: Read the two characters carefully, since a letter and a digit can look alike on a small indoor display at a distance. | Clean or replace the indoor filters following the manual for your unit, then clear the reminder using the remote control. | Time a defrost pause from when heating stops to when it returns, so an unusually long pause can be reported accurately. Qualified technician: A display that Samsung places in its service group, rather than these three, needs an authorised engineer and is not an owner task. | Frost that keeps returning after every defrost cycle, or a defrost pause that never ends, is a fault behind a normal-looking display and should be reported.

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C101/C102 ProfessionalRequired
Samsung • ductless-mini-split — WindFree 3.0 AR C

Samsung WindFree C101 and C102 communication errors

On Samsung WindFree 3.0 AR C systems, C101 and C102 identify failed communication between indoor and outdoor equipment. The service path includes the interconnect cable, its terminal order and continuity, supply conditions, and control boards; the display alone cannot select a part. Applies to: WindFree 3.0 AR C Use this definition only for WindFree 3.0 AR C combinations covered by the cited Samsung service manual. Samsung assigns similar-looking codes differently across RAC, FJM, VRF, and appliance products. Owner-safe checks: Save the exact display, both model plates, first-occurrence timing, and the operating status of any other connected indoor units. Qualified technician: Cable continuity, terminal correction, live communication measurements, and control-board work require a qualified air-conditioning technician.

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C1 (21, 22, 54, 63) ProfessionalRequired
Samsung • ductless-mini-split — Samsung indoor air conditioner units that display the C1 group of service codes described in Samsung support material

Samsung C1 codes: four faults Samsung sends straight to an engineer

Samsung publishes four indoor faults under a C1 heading with a two-digit detail: a defective room temperature sensor, a defective heat exchanger temperature sensor, a fan that is not rotating, and EEPROM data corruption. For all four, Samsung's stated instruction is to contact a service centre, so none of them has an owner-level remedy. Applies to: Samsung indoor air conditioner units that display the C1 group of service codes described in Samsung support material These four entries are drawn from Samsung indoor air conditioner support material. Samsung display conventions differ between generations and regions, and the same four faults appear on other Samsung equipment as longer numeric codes. Confirm against the manual for your own indoor unit before matching a detail digit to a component. Owner-safe checks: Read and photograph the full display, including both parts of the code, before the unit is switched off or the power is interrupted. | Establish whether the indoor fan produces any airflow at any setting, standing clear of the outlet while you check. | Compare the displayed room temperature with a separate thermometer and note both figures with the date. Qualified technician: Samsung's stated instruction for every fault in this group is to contact a service centre, and each of the four sits behind the indoor casing. | Do not run the system with an indoor fan that is not turning. Air moving across the coil is what keeps the refrigerant circuit inside its designed operating range.

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Blink patterns ProfessionalRequired
Ruud • furnace — Ruud gas furnaces whose integrated controls report diagnostics through a blinking indicator, including the R96T range

Ruud blink codes: counting correctly is most of the diagnosis

A Ruud furnace control reports its diagnosis as a number of blinks separated by pauses, and the number is the whole message. Two blinks and three blinks describe different conditions, the pause between groups is easy to miss, and a miscount sends the whole diagnosis somewhere it does not belong. Applies to: Ruud gas furnaces whose integrated controls report diagnostics through a blinking indicator, including the R96T range Blink assignments belong to a control platform rather than to the Ruud name, and they have differed across furnace ranges and generations. The diagnostic label inside the furnace door, and the installation instructions for the model on the rating plate, are the reference for what a given count means. Owner-safe checks: Record a video through the door sight glass across several full repetitions rather than counting by eye. | Keep the blower door closed, since opening it can remove control power and clear the indication. | Write the count down immediately with the date and time, and note whether it has changed between attempts. Qualified technician: Interpreting a count against the diagnostic label, testing components, and any work inside the furnace cabinet are licensed gas-furnace tasks. | A count corresponding to a limit, a rollout, or a flame condition is a stop condition rather than something to observe across further cycles.

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58 ProfessionalRequired
Ruud • furnace — R96T two-stage communicating condensing furnaces

Ruud R96T fault 58: open water-sensor circuit

On the documented Ruud R96T, fault 58 means the water-sensor circuit is open. Depending on the installed configuration, that path can include a water sensor or a required jumper plus its wiring and control input. It is not the same as the combustion pressure-switch codes and does not prove water is present. Applies to: R96T two-stage communicating condensing furnaces This definition is limited to the R96T manual cited here. Rheem and Ruud share some platforms, but model suffix, control generation, optional sensor configuration, and the exact code table still govern the diagnosis. Owner-safe checks: Keep panels closed, photograph fault 58 and the rating plate, and observe only external water or recent drain work from a safe position. Qualified technician: Configuration verification, sensor and jumper access, continuity tests, condensate diagnosis, wiring repair, and control-input checks require qualified furnace service.

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A006_C ProfessionalRequired
Rheem • controls-thermostats — Rheem and Ruud EcoNet communicating systems in which a smart thermostat or control center shares a four-wire network with indoor and outdoor equipment

Rheem EcoNet A006_C outdoor unit communication failure: why a breaker reset holds for a while

The alarm reports that the control is no longer hearing the outdoor unit, which is a statement about the path between them rather than about the outdoor unit itself. Cutting power at the breaker forces the whole network to start again, so a marginal connection that had drifted out of tolerance gets one more chance to work. That is why the system runs afterwards, and it is also why nothing about the restart tells you the connection has been repaired. Applies to: Rheem and Ruud EcoNet communicating systems in which a smart thermostat or control center shares a four-wire network with indoor and outdoor equipment EcoNet is a wired communicating network, and this page describes the network requirements published for Rheem and Ruud EcoNet controls. It does not cover Rheem equipment running on a conventional 24 volt thermostat, where no equivalent alarm exists. Owner-safe checks: Photograph the alarm history and the current alarm screen before interrupting power, because a restart clears the active entry. | Record the outdoor temperature and the time at each occurrence so a repeatable trigger becomes visible. | Note whether the indoor section kept running, which separates a whole-network problem from an outdoor one. Qualified technician: Inspecting the network run for a star branch, and checking terminations at each device, means opening equipment enclosures and is qualified service work. | Measuring supply voltage at a communicating device under load is an energised measurement for a technician.

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57 ProfessionalRequired
Rheem • furnace — R96V communicating condensing gas furnaces

Rheem R96V fault 57: pressure switch open at the wrong time

Rheem R96V fault 57 means the combustion pressure switch is open when the control expects it closed. The furnace can withhold gas heat while other modes remain available. The code does not prove a defective switch because draft, venting, condensate, tubing, inducer, wiring, and actual pressure determine its state. Applies to: R96V communicating condensing gas furnaces This definition applies to R96V furnaces covered by Rheem document 92-24161-184. Other Rheem control generations and water-heating products can assign 57 differently, so use the full furnace model. Owner-safe checks: With panels intact, capture code 57, thermostat demand, inducer sound, time to fault, and safe exterior photos of the vent termination. Qualified technician: Draft measurement, vent and condensate access, inducer testing, tubing inspection, switch verification, wiring, and combustion work require licensed furnace service.

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