Johnson Controls LM8M/LMLM*MP, YM8M/YMLM*MP Diagnostic Fault Code Storage and Retrieval

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368261-UIM-A-0508

Three Red Flashes - Stuck open pressure switch. This indicates that the pressure switch is open when it should be closed. This could be caused by a faulty combustion air blower, blocked vent pipe, blocked air intake pipe, blocked condensate drain, faulty pressure switch hose or a faulty pressure switch.

Four Red Flashes - High limit switch open or 24 volt fuse is open. This may be caused by a dirty air filter, improperly sized duct system, faulty blower motor, restricted circulating airflow or an open fuse on the con- trol board.

Five Red Flashes - Rollout switch or auxiliary limit switch open. Check the rollout switch on the side of the burner box. It is a manual reset switch. To reset, push the small button in the center of the switch. If it cannot be reset or if the switch trips again, contact a qualified service- man. Check the limit switch mounted in the combustion air blower hous- ing.

Six Red Flashes - Current failure on modulating gas valve.

Seven Red Flashes - Lockout due to no ignition. The control will try three times for ignition. If flame cannot be established in three tries, the control will lockout for one hour and then will try again to light. Check gas supply, ignitor, gas valve, flame sensor.

Eight Red Flashes - Lockout due to too many flame recycles. This flash code occurs if flame is lost five times during a single heating cycle. This could be caused by a faulty gas valve, low gas pressure, or dirty flame sensor. The control will lock out for one hour and then will try again.

Nine Red Flashes - Reversed line polarity or improper grounding. Check polarity of the incoming power to the furnace. Check the ground- ing of the furnace, including the transformer ground and the L1 and neutral connections.

Ten Red Flashes - Gas valve circuit shorted. Check gas valve wiring. If correct, replace gas valve.

Eleven Red Flashes - Main blower failure - This flash code occurs when the main limit opens and fails to reclose within five minutes, indi- cating that the blower motor or blower wheel has failed.

Twelve Red Flashes - ID plug is not present or not connected properly, check for loose plug or loose wires in plug.

Steady On Red - Control fault has been detected or there is 24 volts present without 115 volts. Check that there is 24 volts and 115 volts being supplied to the board. If so, then the board should be replaced.

IGNITION CONTROL FLAME SENSE LEVELS Normal flame sense current is approximately 3.7 microamps DC (µa)

Low flame signal warning starts at 1.5 microamps.

Low flame signal control lockout point is

0.1 microamps DC (µa)

DIAGNOSTIC FAULT CODE STORAGE AND RETRIEVAL

The control in this furnace is equipped with memory that will store up to five error codes to allow a service technician to diagnose problems more easily. This memory will be retained even if power to the furnace is lost. Only a qualified service technician should use this feature.

The control stores up to five separate error codes. If more than five error codes have occurred since the last reset, only the five most recent will be retained. The furnace control board has a button, labeled "LAST ERROR" that is used to retrieve error codes. This function will only work if there are no active thermostat signals. So any call for heating, cooling or continuous fan must be terminated before attempting to retrieve error codes.

To retrieve the error codes, push the LAST ERROR button. The LED on the control will then flash the error codes that are in memory, starting with the most recent. There will be a two-second pause between each flash code. After the error codes have all been displayed, the LED will resume the normal slow green flash after a five second pause. To repeat the series of error codes, push the button again.

If there are no error codes in memory, the LED will flash two green flashes. To clear the memory, push the LAST ERROR button and hold it for more than five seconds. The LED will flash three green flashes when the memory has been cleared, then will resume the normal slow green flash after a five-second pause.

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Johnson Controls Unitary Products

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Contents List of Sections Section I SafetyModels List of FiguresAnce to a 50 HZ Power Supply or a Voltage Above 130 Volts Specific Safety Rules and PrecautionsSafety Requirements Combustion AIR Quality List of ContaminantsCodes and Standards InspectionDuctwork General Information Section II DuctworkFurnace Location and Clearances Furnace Assembly MC & FC Series Coils Floor Base and Ductwork Installation DownflowCOIL/FURNACE Assembly MC/FC/PC Series Coils Coil Flange InstallationDownflow Duct Connectors Furnace Assembly PC Series CoilsCoil / Furnace Assembly HC Series Coils Critical Coil ProjectionSuspended Furnace / Crawl Space Installation Bottom Return and Attic InstallationsAttic Installation Horizontal ApplicationSection III Filters Filter InstallationAttempt to install filters inside the furnace Side ReturnSection IV GAS Piping GAS SafetyGAS Piping Installation GAS Conversion for Propane LPHigh Altitude Natural GAS Orifice Conversion Section V Electrical PowerElectrical Power Connections AIR Conditioner Connections LOW Voltage Control Wiring ConnectionsSupply Voltage Connections Zoning OperationThermostat ID ModelsModulating TWO Stage AIR Furnace Conditioner UIM-A-0508 Modulating Furnace OD Models Single Stage Heat PumpThermostat Modulating Furnace TWO Stage Heat PumpSection VI Twinning and Staging Section VII Vent SystemAir Supply Openings and Ducts Combustion Air Source From OutdoorsDampers, Louvers and Grilles Canada Only Free AreaVentilated Combustion Air Section Viii START-UP AdjustmentsVent and Supply Outside Air Safety Check Procedure NOx Screen Removal Lo-NOx Models OnlyCalculating the Furnace Input Natural GAS Setup Test ModeGAS Piping Leak Check Seconds For Revolution Cu FtAdjustment of Manifold GAS Pressure Adjustment of Temperature RiseBlower Door Safety Switch Section IX Safety ControlsAdjustment of FAN Control Settings Rollout Switch ControlsPressure Controls Section X Normal Operation and DiagnosticsFurnace Control Diagnostics Limit ControlsDiagnostic Fault Code Storage and Retrieval Section XI Replacement Parts List Fabricated PartsSection XII Wiring Diagram Johnson Controls Unitary Products York Drive Norman, OK

LM8M/LMLM*MP, TM8M/TMLM*MP, CM8M/CMLM*MP, YM8M/YMLM*MP specifications

Johnson Controls TM8M/TMLM*MP, YM8M/YMLM*MP, LM8M/LMLM*MP, and CM8M/CMLM*MP are advanced temperature controllers designed for a wide range of applications in heating, ventilation, and air conditioning (HVAC) systems. These models stand out due to their robust features, cutting-edge technologies, and specific characteristics that cater to both residential and commercial environments.

One of the main features of the TM8M/TMLM*MP series is its user-friendly interface that incorporates a large, easy-to-read display. This allows for quick adjustments and monitoring of temperature settings, making it accessible for both skilled technicians and everyday users. The intuitive design ensures that users can efficiently navigate through various settings and configurations.

Another notable characteristic is the flexibility of these controllers. The series supports multiple sensor configurations, enabling the integration of both wired and wireless sensors. This adaptability allows users to customize their climate control systems according to specific needs and room layouts, ultimately enhancing comfort and energy efficiency.

The TM8M/TMLM*MP and its counterparts are equipped with sophisticated algorithms that optimize energy consumption. By utilizing predictive maintenance and intelligent analytics, these controllers can adjust settings dynamically based on real-time data. This not only helps in reducing operational costs but also prolongs the lifespan of HVAC equipment.

Incorporating advanced communication protocols is a hallmark of the Johnson Controls series. The TM8M and CM8M models support modern systems such as BACnet and Modbus, allowing seamless integration with building management systems (BMS). This compatibility ensures that users can maintain centralized control over multiple systems, enhancing overall operational efficiency.

Additionally, the series is robustly constructed to withstand harsh environmental conditions. Its durable casing and reliable components ensure long-term performance, making it suitable for a variety of settings, including industrial facilities and commercial properties.

Safety features are also integral to the design of the TM8M/TMLM*MP and related models. Built-in safeguards protect against over-temperature and other potential hazards, ensuring reliability and peace of mind for operators.

In summary, Johnson Controls TM8M/TMLM*MP, YM8M/YMLM*MP, LM8M/LMLM*MP, and CM8M/CMLM*MP controllers represent a convergence of user-friendly design, advanced technology, flexibility, and safety. Their ability to adapt to diverse applications while optimizing energy use makes them a critical component in modern HVAC systems, ensuring comfort and efficiency in every environment.
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