Goodman R-32 A2L Refrigerant Detection Sensor, SER2A05012S (5 ft Lead)
The Goodman SER2A05012S is the OEM A2L refrigerant detection sensor called out in the factory repair parts manuals for Goodman AMST, Amana AWST and 2 to 2.5 ton Goodman AMVT R-32 air handlers. Built by Sensata for Daikin North America and supplied with a 5-foot lead, it mounts in the sensor bracket at the drain pan and continuously samples cabinet air for R-32 concentration, reporting to the air handler's A2L control board. It is the correct replacement when a factory sensor faults, is damaged during service, or leaves an air handler locked in leak mitigation mode — and the 5-foot lead is what separates it from the longer SER2A08012S used on cased coils and the larger AMVT cabinets.
Which Goodman and Amana R-32 Units Take the SER2A05012S?
An A2L sensor is chosen by the part number printed in your unit's repair parts manual, not by tonnage or refrigerant alone. Goodman ships two A2L sensors across its R-32 lineup and they differ by lead length: the SER2A05012S carries a 5-foot lead, while the SER2A08012S carries an 8-foot lead for cabinets and cased coils where the harness has to travel farther to reach a furnace board or integration kit. They are not interchangeable in either direction.
Per Goodman's factory parts documentation, the SER2A05012S is the specified sensor for every AMST R-32 air handler from 2 through 5 tons, for all Amana AWST R-32 air handlers, and for the two smallest AMVT variable-speed air handlers — the 2 ton AMVT24BP1300 and the 2.5 ton AMVT30BP1300. The 3 through 5 ton AMVT models and the CAPTA, CAPEA and CHPTA R-32 cased coils use the 8-foot SER2A08012S instead. Confirm against your parts manual before ordering.
Ideal for: HVAC service technicians replacing a failed or damaged A2L sensor in a Goodman AMST, Amana AWST, or 2 to 2.5 ton Goodman AMVT R-32 air handler; clearing a unit stuck in leak mitigation with a sensor communication or internal sensor fault; or completing a coil-assembly repair where the original sensor was lost.
Working on a cased coil or a larger AMVT instead? Those call for the 8-foot SER2A08012S. If you are pairing an R-32 coil to older equipment, you will also want the Goodman Furnace Integration Kit 0230K00044 or the Goodman Zoning Integration Kit for R-32 Systems 0230K00007 so a non-A2L furnace or zoning panel can read the sensor and run the required mitigation sequence.
This sensor is approved only for equipment listed for R-32. It cannot be installed on an existing R-410A or R-22 coil, or on any system not approved for A2L refrigerant, and it must be replaced only with the sensor specified by the appliance manufacturer. Request part verification, contact Budget Heating, or call 813-885-7999.
What's Included
| Part | SER2A05012S — A2L Refrigerant Detection Sensor |
|---|---|
| OEM Brand | Goodman / Amana (Daikin North America) |
| Sensor Manufacturer | Sensata Technologies |
| Lead Length | 5 ft — the 8 ft version is SER2A08012S |
| Refrigerant Monitored | R-32 (A2L) |
| Specified For | Goodman AMST R-32 (All Models), Amana AWST R-32 (All Models), Goodman AMVT24BP1300 and AMVT30BP1300 |
| Mounting | Push-Pin Retained on the Factory Sensor Bracket at the Drain Pan |
| Connection | Sensor Wire to the A2L Control Board (PCBCM301V0001 on AMST) |
| Not Approved For | R-410A, R-22, or Any System Not Listed for R-32 |
| Quantity | Sold Individually — One (1) Sensor |
This is a single-component service part rather than a kit. It replaces the sensor element only — the bracket, push-pin retainers, harness routing and A2L control board already in your air handler are reused. Because the sensor is what authorizes the equipment to run normally, a failed or unplugged unit does not simply log a code: it holds the air handler in mitigation mode, with heating and cooling disconnected, until a specified replacement restores communication.
Sensor Function & System Integration
SER2A05012S Sensor Construction & Detection
- Genuine OEM A2L refrigerant detection sensor, Goodman and Amana part number SER2A05012S
- Manufactured by Sensata Technologies for Daikin North America, parent company of Goodman and Amana
- Supplied with a 5-foot lead sized for AMST, AWST and 2 to 2.5 ton AMVT cabinets
- Detects R-32 refrigerant concentration in the air inside the air handler cabinet
- Mounts on the factory sensor bracket at the drain pan, the lowest point where heavier-than-air R-32 collects
- Retained by plastic push pins for a tool-light swap once the bracket is out
- Continuous monitoring — the control board polls the sensor roughly once per second
- Fully passive during normal operation, with no effect on airflow, capacity or efficiency until refrigerant is detected
- Engineered to last the service life of the coil it is installed in
- Direct one-for-one OEM replacement — no board reprogramming required
Control Board Integration, Diagnostics & Mitigation
- Wires directly to the A2L control board in Goodman and Amana R-32 air handlers
- Also supported by the non-A2L furnace integration kit and the A2L accessory and zoning control kit on split installations
- On detection, the refrigerant detection system turns off the thermostat call and disconnects heating and cooling
- Indoor blower is forced on to circulate and dilute refrigerant inside the cabinet
- Electric heat is switched off for the duration of the alarm
- Board LED shows a fast continuous flash during an R-32 leak alarm and a slow two-on, two-off pattern in normal operation
- Diagnostics separate a sensor communication fault from an internal sensor fault, so you can tell a wiring problem from a dead sensor
- Five-minute delay mode runs the blower after the alarm clears before normal operation resumes
- Built-in system verification mode simulates an alarm so the mitigation sequence can be proof-tested after replacement
- Sensor must be connected before the unit is energized, or the system will start in mitigation mode
Frequently Asked Questions
Does the SER2A05012S only work on cased coils, or does it fit Goodman air handlers too?
Air handlers are its primary application. Goodman's factory repair parts manuals specify the SER2A05012S for every AMST R-32 air handler from 2 through 5 tons, for all Amana AWST R-32 air handlers, and for the 2 ton AMVT24BP1300 and 2.5 ton AMVT30BP1300. The CAPTA, CAPEA and CHPTA R-32 cased coils and the 3 through 5 ton AMVT models use the longer-lead SER2A08012S instead.
What is the difference between SER2A05012S and SER2A08012S?
Lead length. The SER2A05012S ships with a 5-foot lead and the SER2A08012S with an 8-foot lead, for cabinets and cased coils where the harness has to reach farther to a furnace control board or integration kit. Both are Sensata A2L sensors supplied for R-32 Goodman and Amana equipment, but they are separate part numbers and are not interchangeable in either direction. Order whichever number your unit's parts manual lists.
Can this sensor be added to an R-410A or R-22 system?
No. It is approved only for indoor equipment engineered and listed for R-32. It cannot be retrofitted to an existing R-410A or R-22 coil, and it must not be installed on any system not approved for A2L refrigerant.
My R-32 air handler is stuck in mitigation with the LED flashing. Is the sensor at fault?
Possibly. Mitigation is triggered by an actual refrigerant detection, by a sensor that has failed internally, or by a sensor the board cannot talk to — including one that was not plugged in before the unit was powered up. Rule out a real leak first, then check the sensor wire at the board, then read the LED flash pattern: the board reports a communication fault and an internal sensor fault differently, which tells you whether you are chasing wiring or replacing the part.
Where is the sensor located, and how is it replaced?
It sits on a sensor bracket assembly at the drain pan inside the air handler. To swap it, pull the access panels, disconnect the sensor wire from the A2L control board, remove the bracket assembly from the drain pan, pop the plastic push pins and lift the failed sensor off the bracket, then fit the new sensor with new push pins and reconnect to the board. Goodman's manual is explicit that the sensor be replaced only with a sensor specified by the appliance manufacturer.
Should I replace the A2L control board at the same time?
Not automatically. The sensor and the board are separate parts — on AMST air handlers the board is PCBCM301V0001 — and the board's own fault codes will tell you which one is failing. An internal sensor fault points at the sensor; a
