{"product_id":"new-carel-mch2000031-temperature-controller-1","title":"CAREL MCH2000031 μC2SE Temperature Controller for Chiller Systems","description":"\u003cdiv class=\"koeed-container\"\u003e\n    \u003ch2\u003eEngineer's Quick Brief\u003c\/h2\u003e\n    \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eComprehensive I\/O Capacity:\u003c\/strong\u003e Features 5 SPST digital relay outputs, 4 analog NTC temperature probe inputs (10 kΩ at 25°C), and 5 volt-free digital inputs for complete control over compressors, pumps, and fans.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eNative Chiller \u0026amp; Heat Pump Logic:\u003c\/strong\u003e Pre-programmed with advanced thermodynamic algorithms, including precision anti-freeze protection, automated defrost cycles, and compressor wear-leveling (rotation).\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eSeamless BMS Integration:\u003c\/strong\u003e Operates on a standard \u003cstrong\u003e24 Vac\u003c\/strong\u003e supply and supports RS485 serial communication using the Modbus RTU protocol for centralized Building Management System monitoring.\u003c\/li\u003e\n    \u003c\/ul\u003e\n\n    \u003ch2\u003eSEO Introduction\u003c\/h2\u003e\n    \u003cp\u003eThe \u003cstrong\u003eCAREL MCH2000031\u003c\/strong\u003e, an integral model within the renowned \u003cstrong\u003eμC2SE (microC2 SE)\u003c\/strong\u003e series, is a high-performance microprocessor-based electronic temperature controller explicitly engineered for chillers, heat pumps, and roof-top condensing units. Operating robustly on a \u003cstrong\u003e24 Vac (+10\/-15%)\u003c\/strong\u003e power supply, this industrial-grade controller delivers unparalleled precision in thermodynamic system regulation. Equipped with highly configurable analog and digital I\/O arrays, the MCH2000031 independently manages complex compressor staging, dynamic condenser fan speeds, and critical safety interlocks (such as flow switches and high-pressure sensors). Its compact, dual-purpose design allows for both DIN-rail and panel mounting, making it a ubiquitous standard for commercial HVAC panel builders and refrigeration OEMs worldwide.\u003c\/p\u003e\n\n    \u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n    \u003cdiv style=\"overflow-x: auto;\"\u003e\n        \u003ctable class=\"koeed-table\"\u003e\n            \u003cthead\u003e\n                \u003ctr\u003e\n                    \u003cth\u003eSpecification Category\u003c\/th\u003e\n                    \u003cth\u003eTechnical Details\u003c\/th\u003e\n                \u003c\/tr\u003e\n            \u003c\/thead\u003e\n            \u003ctbody\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003e\u003cstrong\u003eManufacturer\u003c\/strong\u003e\u003c\/td\u003e\n                    \u003ctd\u003eCAREL\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003e\u003cstrong\u003eModel Number\u003c\/strong\u003e\u003c\/td\u003e\n                    \u003ctd\u003eMCH2000031 (μC2SE Series)\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003e\u003cstrong\u003ePower Supply\u003c\/strong\u003e\u003c\/td\u003e\n                    \u003ctd\u003e24 Vac (+10\/-15%), 50\/60 Hz\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003e\u003cstrong\u003ePower Consumption\u003c\/strong\u003e\u003c\/td\u003e\n                    \u003ctd\u003e3 W (Maximum)\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003e\u003cstrong\u003eAnalog Inputs\u003c\/strong\u003e\u003c\/td\u003e\n                    \u003ctd\u003e4 x NTC Temperature Probes (Standard CAREL 10 kΩ at 25°C)\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003e\u003cstrong\u003eDigital Inputs\u003c\/strong\u003e\u003c\/td\u003e\n                    \u003ctd\u003e5 x Opto-isolated Free Contact (Volt-Free) Inputs\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003e\u003cstrong\u003eDigital Outputs (Relays)\u003c\/strong\u003e\u003c\/td\u003e\n                    \u003ctd\u003e5 x SPST Relays (Rated 2A normal, extendable to 3A for single output)\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003e\u003cstrong\u003eOperating Temperature\u003c\/strong\u003e\u003c\/td\u003e\n                    \u003ctd\u003e-10°C to 55°C (14°F to 131°F)\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003e\u003cstrong\u003eCommunication Interface\u003c\/strong\u003e\u003c\/td\u003e\n                    \u003ctd\u003eRS485 Serial (Modbus RTU via optional expansion card)\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003e\u003cstrong\u003eProtection Rating\u003c\/strong\u003e\u003c\/td\u003e\n                    \u003ctd\u003eIP65 (Front Panel) \/ IP40 (Rear Case)\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003e\u003cstrong\u003eMounting Options\u003c\/strong\u003e\u003c\/td\u003e\n                    \u003ctd\u003ePanel Mount or DIN Rail compatible\u003c\/td\u003e\n                \u003c\/tr\u003e\n            \u003c\/tbody\u003e\n        \u003c\/table\u003e\n    \u003c\/div\u003e\n\n    \u003ch2\u003eApplication Matrix\u003c\/h2\u003e\n    \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eCommercial Process Chillers:\u003c\/strong\u003e Provides granular regulation of evaporator leaving-water temperatures, seamlessly managing flow switch interlocks to prevent catastrophic freezing in industrial cooling loops.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eAir-to-Water Heat Pumps:\u003c\/strong\u003e Executes intelligent reverse-cycle defrosting logic based on ambient coil temperatures, maximizing heating efficiency during winter conditions.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eData Center Precision Cooling:\u003c\/strong\u003e Integrates directly into Modbus RTU networks, allowing facility managers to remotely monitor NTC probe data, adjust setpoints, and receive real-time compressor fault alarms.\u003c\/li\u003e\n    \u003c\/ul\u003e\n\n    \u003ch2\u003eCAREL μC2SE Alarm \u0026amp; Error Code Decoder\u003c\/h2\u003e\n    \u003cp\u003eField technicians can use this diagnostic tool to instantly decode alphanumeric alarm codes displayed on the MCH2000031 screen. Select the exact fault code to reveal the root cause and factory-recommended FAE troubleshooting actions.\u003c\/p\u003e\n    \n    \u003cnoscript\u003e\n        \u003cp\u003e\u003cem\u003ePlease enable JavaScript to utilize the interactive alarm decoder. Refer to the manual or the FAQ section below for text-based diagnostic assistance.\u003c\/em\u003e\u003c\/p\u003e\n    \u003c\/noscript\u003e\n\n    \u003cdiv class=\"koeed-tool-wrapper\"\u003e\n        \u003clabel for=\"koeed-alarm-selector\" style=\"font-weight: bold; color: #0056b3;\"\u003eSelect Controller Alarm Code:\u003c\/label\u003e\n        \u003cselect id=\"koeed-alarm-selector\" onchange=\"koeedDecodeAlarm()\"\u003e\n            \u003coption value=\"none\"\u003e-- Select Alarm Code --\u003c\/option\u003e\n            \u003coption value=\"e01\"\u003eE01 \/ E02 \/ E03 \/ E04 (Probe Faults)\u003c\/option\u003e\n            \u003coption value=\"hp1\"\u003eHP1 \/ HP2 (High Pressure Alarm)\u003c\/option\u003e\n            \u003coption value=\"lp1\"\u003eLP1 \/ LP2 (Low Pressure Alarm)\u003c\/option\u003e\n            \u003coption value=\"fl\"\u003eFL (Flow Switch Alarm)\u003c\/option\u003e\n            \u003coption value=\"a1\"\u003eA1 \/ AFr (Anti-Freeze Alarm)\u003c\/option\u003e\n            \u003coption value=\"ee\"\u003eEE (EEPROM Memory Error)\u003c\/option\u003e\n        \u003c\/select\u003e\n        \u003cdiv id=\"koeed-tool-result\" class=\"koeed-result-box\" style=\"display:none;\"\u003e\u003c\/div\u003e\n    \u003c\/div\u003e\n\n    \u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n    \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eHow do I verify a faulty NTC temperature probe (E01 error)?\u003c\/strong\u003e Disconnect the suspected probe from the controller terminals. Using a multimeter, measure its resistance. A standard CAREL NTC probe should read approximately 10 kΩ at 25°C (77°F). If it reads open circuit (infinite resistance) or a direct short, the probe must be replaced.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eWhy does the unit persistently trigger a \"FL\" (Flow) alarm?\u003c\/strong\u003e The controller detects that the digital input assigned to the water flow switch is open. Verify that the chilled water pump is operating, bleed any air trapped in the piping system, and confirm the mechanical paddle switch is actually making electrical contact when water flows.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eHow can I manually reset a lockout alarm on the MCH2000031?\u003c\/strong\u003e Most auto-reset alarms clear themselves when conditions normalize. For manual-reset lockout alarms (like severe High Pressure HP1 or Anti-freeze), you typically need to resolve the physical fault first, then press and hold the \"Alarm\/Mute\" or \"UP+DOWN\" button combination for 3-5 seconds until the relay resets.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eCan I connect the μC2SE directly to a 230V mains supply?\u003c\/strong\u003e No. The MCH2000031 specifically requires a 24 Vac low-voltage supply. Connecting 110V or 230V directly to the power terminals will instantly destroy the internal circuitry. Always use an appropriately sized 230V-to-24V step-down control transformer.\u003c\/li\u003e\n    \u003c\/ul\u003e\n\n    \u003ch3\u003eCross-Reference Guide\u003c\/h3\u003e\n    \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eSystem Expansion:\u003c\/strong\u003e If your system requires control of a second refrigerant circuit, the MCH2000031 is fully compatible with the \u003cstrong\u003eMCH2000020\u003c\/strong\u003e I\/O expansion board via the tLAN connection.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eSeries Compatibility:\u003c\/strong\u003e Serves as a direct replacement or functional upgrade for legacy standard μC2 models, provided the panel cut-out and 24Vac power infrastructure remain consistent.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eCommunication Hardware:\u003c\/strong\u003e To activate the Modbus RS485 feature, the optional CAREL serial expansion card (e.g., MCHRS48500 or equivalent) must be inserted into the designated slot on the controller.\u003c\/li\u003e\n    \u003c\/ul\u003e\n\n\u003c\/div\u003e\n\n\u003cstyle\u003e\n    .koeed-container {\n        width: 100%;\n        color: #333;\n        line-height: 1.6;\n    }\n    .koeed-container h2 {\n        color: #0056b3;\n        border-bottom: 2px solid #16c8c8;\n        padding-bottom: 5px;\n        margin-top: 30px;\n    }\n    .koeed-container h3 {\n        color: #0056b3;\n        margin-top: 20px;\n    }\n    .koeed-container ul, .koeed-container ol {\n        padding-left: 20px;\n    }\n    .koeed-container li {\n        margin-bottom: 10px;\n    }\n    .koeed-container strong {\n        color: #111;\n    }\n    .koeed-table {\n        width: 100%;\n        border-collapse: collapse;\n        margin-top: 15px;\n        margin-bottom: 15px;\n        min-width: 600px;\n    }\n    .koeed-table th, .koeed-table td {\n        border: 1px solid #eeeeee;\n        padding: 12px;\n        text-align: left;\n    }\n    .koeed-table th {\n        background-color: #0056b3;\n        color: #ffffff;\n    }\n    .koeed-table tbody tr:nth-child(odd) {\n        background-color: #f4fcfc;\n    }\n    .koeed-table tbody tr:nth-child(even) {\n        background-color: #fafafa;\n    }\n    .koeed-tool-wrapper {\n        background-color: #f4fcfc;\n        border: 1px solid #16c8c8;\n        border-radius: 6px;\n        padding: 20px;\n        margin: 20px 0;\n    }\n    .koeed-tool-wrapper select {\n        width: 100%;\n        padding: 10px;\n        margin-top: 10px;\n        border: 1px solid #ccc;\n        border-radius: 4px;\n        font-size: 16px;\n    }\n    .koeed-result-box {\n        margin-top: 20px;\n        padding: 15px;\n        background-color: #ffffff;\n        border-left: 4px solid #16c8c8;\n        border-radius: 4px;\n    }\n\u003c\/style\u003e\n\n\u003cscript\u003e\n    function koeedDecodeAlarm() {\n        var selector = document.getElementById('koeed-alarm-selector');\n        var resultBox = document.getElementById('koeed-tool-result');\n        var val = selector.value;\n        \n        var msg = \"\";\n        \n        switch(val) {\n            case \"e01\":\n                msg = \"\u003cstrong\u003eAlarm Type:\u003c\/strong\u003e NTC Analog Probe Fault.\u003cbr\u003e\u003cstrong\u003eRoot Cause:\u003c\/strong\u003e The specified probe (B1 for E01, B2 for E02, etc.) is either disconnected, reading outside limits, or short-circuited.\u003cbr\u003e\u003cstrong\u003eAction:\u003c\/strong\u003e Use a multimeter to verify probe resistance (should be ~10 kΩ at 25°C). Inspect terminal block wiring for loose connections. Replace the probe if defective.\";\n                break;\n            case \"hp1\":\n                msg = \"\u003cstrong\u003eAlarm Type:\u003c\/strong\u003e High Pressure Alarm (Circuit 1\/2).\u003cbr\u003e\u003cstrong\u003eRoot Cause:\u003c\/strong\u003e Refrigerant discharge pressure has exceeded the safety limit, triggering the mechanical high-pressure switch linked to the digital input.\u003cbr\u003e\u003cstrong\u003eAction:\u003c\/strong\u003e Verify condenser fan operation. Clean blocked condenser coils. Ensure ambient temperature is within limits. Check for refrigerant overcharge.\";\n                break;\n            case \"lp1\":\n                msg = \"\u003cstrong\u003eAlarm Type:\u003c\/strong\u003e Low Pressure Alarm (Circuit 1\/2).\u003cbr\u003e\u003cstrong\u003eRoot Cause:\u003c\/strong\u003e Suction pressure has dropped below the safety threshold, often accompanied by the compressor shutting down to prevent frosting or oil loss.\u003cbr\u003e\u003cstrong\u003eAction:\u003c\/strong\u003e Inspect for refrigerant system leaks (low charge). Verify proper operation of the electronic\/thermostatic expansion valve. Check evaporator water flow.\";\n                break;\n            case \"fl\":\n                msg = \"\u003cstrong\u003eAlarm Type:\u003c\/strong\u003e Water Flow Switch Alarm.\u003cbr\u003e\u003cstrong\u003eRoot Cause:\u003c\/strong\u003e The digital input designated for the flow switch is open circuit, indicating insufficient or no fluid flow across the evaporator.\u003cbr\u003e\u003cstrong\u003eAction:\u003c\/strong\u003e Verify the chilled water pump is active. Clean the Y-strainer\/water filter. Bleed trapped air from the hydraulic circuit. Test the mechanical flow switch for continuity.\";\n                break;\n            case \"a1\":\n                msg = \"\u003cstrong\u003eAlarm Type:\u003c\/strong\u003e Anti-Freeze Alarm.\u003cbr\u003e\u003cstrong\u003eRoot Cause:\u003c\/strong\u003e The evaporator leaving water temperature probe has dropped to a critical freezing threshold. The system shuts down the compressor to prevent heat exchanger rupture.\u003cbr\u003e\u003cstrong\u003eAction:\u003c\/strong\u003e Ensure adequate water flow. Check if the anti-freeze setpoint matches the fluid type (water vs. glycol mix). Inspect probe B2 for accurate reading.\";\n                break;\n            case \"ee\":\n                msg = \"\u003cstrong\u003eAlarm Type:\u003c\/strong\u003e EEPROM \/ Retain Memory Error.\u003cbr\u003e\u003cstrong\u003eRoot Cause:\u003c\/strong\u003e The controller has encountered an internal read\/write error in its non-volatile memory.\u003cbr\u003e\u003cstrong\u003eAction:\u003c\/strong\u003e Completely remove power from the 24Vac terminals, wait 30 seconds, and restore power (Cold Boot). If the error persists, the MCH2000031 controller board must be replaced.\";\n                break;\n            default:\n                resultBox.style.display = \"none\";\n                return;\n        }\n        \n        resultBox.innerHTML = msg;\n        resultBox.style.display = \"block\";\n    }\n\u003c\/script\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@graph\": [\n    {\n      \"@type\": \"FAQPage\",\n      \"mainEntity\": [\n        {\n          \"@type\": \"Question\",\n          \"name\": \"How do I verify a faulty NTC temperature probe (E01 error)?\",\n          \"acceptedAnswer\": {\n            \"@type\": \"Answer\",\n            \"text\": \"Disconnect the suspected probe from the controller terminals. Using a multimeter, measure its resistance. A standard CAREL NTC probe should read approximately 10 kΩ at 25°C (77°F). If it reads open circuit (infinite resistance) or a direct short, the probe must be replaced.\"\n          }\n        },\n        {\n          \"@type\": \"Question\",\n          \"name\": \"Why does the unit persistently trigger a FL (Flow) alarm?\",\n          \"acceptedAnswer\": {\n            \"@type\": \"Answer\",\n            \"text\": \"The controller detects that the digital input assigned to the water flow switch is open. Verify that the chilled water pump is operating, bleed any air trapped in the piping system, and confirm the mechanical paddle switch is actually making electrical contact when water flows.\"\n          }\n        },\n        {\n          \"@type\": \"Question\",\n          \"name\": \"How can I manually reset a lockout alarm on the MCH2000031?\",\n          \"acceptedAnswer\": {\n            \"@type\": \"Answer\",\n            \"text\": \"Most auto-reset alarms clear themselves when conditions normalize. For manual-reset lockout alarms (like severe High Pressure HP1 or Anti-freeze), you typically need to resolve the physical fault first, then press and hold the 'Alarm\/Mute' or 'UP+DOWN' button combination for 3-5 seconds until the relay resets.\"\n          }\n        },\n        {\n          \"@type\": \"Question\",\n          \"name\": \"Can I connect the μC2SE directly to a 230V mains supply?\",\n          \"acceptedAnswer\": {\n            \"@type\": \"Answer\",\n            \"text\": \"No. The MCH2000031 specifically requires a 24 Vac low-voltage supply. Connecting 110V or 230V directly to the power terminals will instantly destroy the internal circuitry. Always use an appropriately sized 230V-to-24V step-down control transformer.\"\n          }\n        }\n      ]\n    },\n    {\n      \"@type\": \"WebApplication\",\n      \"name\": \"CAREL μC2SE Alarm \u0026 Error Code Decoder\",\n      \"description\": \"An interactive frontend diagnostic tool for field engineers to quickly translate CAREL MCH2000031 \/ uC2SE display alarm codes into direct root causes and troubleshooting actions.\",\n      \"applicationCategory\": \"UtilitiesApplication\",\n      \"operatingSystem\": \"All\",\n      \"browserRequirements\": \"Requires JavaScript execution.\"\n    }\n  ]\n}\n\u003c\/script\u003e","brand":"CAREL","offers":[{"title":"Default Title","offer_id":44483192455353,"sku":"386527611845","price":592.22,"currency_code":"USD","in_stock":true}],"url":"https:\/\/koeed.com\/pl\/products\/new-carel-mch2000031-temperature-controller-1","provider":"KOEED","version":"1.0","type":"link"}