Samsung DVM S (Digital Variable Multi) VRF systems use a 3-digit error code format that displays on the 7-segment LED panel on the outdoor unit PCB. Unlike the indoor remote controller C-series codes, these outdoor codes provide direct fault information from the inverter, compressor, sensors, and safety circuits.
The code structure follows a consistent pattern. The first digit indicates the fault category. The second and third digits narrow the specific component.
- E1xx: Communication faults between indoor units, outdoor units, and branch controllers
- E2xx: Sensor faults on temperature and pressure inputs
- E3xx: Compressor drive and inverter protection faults
- E4xx: Electronic expansion valve (EEV) faults
- E5xx: Safety protection faults including high/low pressure and discharge temperature
This guide covers the most common codes in each category and the diagnostic steps that fix them.
DVM S Outdoor PCB 7-Segment Code Reference
| Code | Category | Description |
|---|---|---|
| E100 | Communication | Outdoor unit PCB internal fault |
| E101 | Communication | Central controller communication failure |
| E102 | Communication | Network communication error between outdoor modules |
| E108 | Communication | HS Link cable communication problem |
| E109 | Communication | Module addressing conflict |
| E201 | Sensor | Outdoor ambient temperature sensor fault |
| E202 | Sensor | Outdoor heat exchanger temperature sensor fault |
| E203 | Sensor | Suction temperature sensor fault |
| E204 | Sensor | Discharge temperature sensor fault |
| E205 | Sensor | Liquid pipe temperature sensor fault |
| E206 | Sensor | High-pressure sensor fault |
| E207 | Sensor | Low-pressure sensor fault |
| E302 | Compressor | DC link voltage low |
| E304 | Compressor | Compressor starting failure |
| E307 | Compressor | Inverter DC peak overcurrent |
| E312 | Compressor | PFC (Power Factor Correction) circuit fault |
| E316 | Compressor | DC link voltage low (3-phase input) |
| E321 | Compressor | Compressor overcurrent protection |
| E401 | Valve | EEV coil open or short circuit |
| E402 | Valve | EEV step motor fault |
| E404 | Valve | EEV operation failure |
| E501 | Safety | High pressure protection |
| E502 | Safety | Low pressure protection |
| E504 | Safety | Discharge temperature over 230°F |
| E505 | Safety | Compressor oil return fault |
| E508 | Safety | Condenser high temperature |
E1xx — Communication Faults
The DVM S system uses a proprietary HS Link communication protocol on a two-wire shielded cable. All indoor units, outdoor units, and branch controllers connect to this bus.
E101 — Central Controller Communication
The outdoor unit lost communication with the central controller or network manager. Check the HS Link cable connections at both ends. Verify that all indoor units have unique addresses. A duplicate address causes the entire bus to drop.
E108 — HS Link Cable Fault
The physical HS Link wiring has a problem. Measure continuity on both conductors. The cable must be a twisted, shielded pair with the drain wire grounded at one end only. DVM S systems are sensitive to cable length. Total HS Link cable length cannot exceed 3,280 feet (1,000 meters) without a repeater.
E109 — Module Addressing Conflict
Two or more outdoor modules on the same network bus have the same address. Each outdoor unit must have a unique DIP switch address. Cycle power after changing the address.
E2xx — Sensor Faults
Samsung DVM S outdoor units use 10k ohm thermistors for temperature sensing and pressure transducers for high-side and low-side pressure readings.
E201 to E205 — Temperature Sensor Faults
Each temperature sensor delivers a resistance value to the outdoor PCB. Check resistance at the sensor connector. A good 10k thermistor reads approximately 10k ohms at 77°F, 3.3k ohms at 122°F, and 32k ohms at 32°F. An open circuit (infinite resistance) means a broken sensor or cut wire. A short (near zero ohms) means damaged insulation or moisture intrusion.
If resistance is correct but the code persists, the wiring harness between the sensor and the outdoor PCB has failed. Check for corrosion at the connector pins.
E206 — High-Pressure Sensor Fault
The high-pressure transducer sends a 0 to 5 VDC signal to the PCB. With the system off and pressures equalized, the sensor should read approximately 1.5 to 2.0 VDC on R-410A systems. A steady 0 VDC or 5 VDC indicates a failed sensor or open circuit.
E207 — Low-Pressure Sensor Fault
Same diagnostic principle. With the system off, the low-pressure sensor should read the same voltage as the high-pressure sensor because system pressure is equalized. A voltage mismatch when the system is off confirms a bad sensor.
E3xx — Compressor and Inverter Faults
The DVM S uses a variable-speed scroll compressor driven by a three-phase inverter. The inverter section includes the rectifier, DC bus capacitors, IGBT modules, and PFC circuit.
E302 — DC Link Voltage Low
The DC bus voltage between the rectifier output and the inverter input is below the minimum threshold. On a 3-phase 208-240V system, normal DC bus voltage is 300 to 350 VDC. On a 460V system, normal DC bus voltage is 600 to 680 VDC.
Measure DC bus voltage at the inverter board test points. If the voltage is normal at idle but drops when the compressor tries to start, the problem is on the AC input side. Check all three phases for voltage drop under load. A weak connection in the disconnect switch or contactor can pass a static voltage check and still collapse under compressor current draw.
If DC bus voltage is low at idle, the rectifier diodes or PFC board have failed.
E304 — Compressor Starting Failure
The inverter tried to start the compressor but did not detect rotation within a set time window. Check compressor winding resistance. On a DVM S scroll compressor, all three windings should show balanced resistance within 5% of each other. A large imbalance between phases indicates an open or shorted winding.
Also verify that the compressor is not mechanically locked. Remove power, pull the disconnect, and check for freedom of rotation with an amp clamp during a brief start attempt.
E307 — Inverter DC Peak Overcurrent
The inverter detected a current spike that exceeded the IGBT module rating. This fault is almost always a failed inverter PBA (Printed Board Assembly) or a compressor with shorted windings. Swap the inverter PBA first if available. If the fault follows the compressor, replace the compressor.
E312 — PFC Circuit Fault
The Power Factor Correction circuit is not operating correctly. The PFC stage boosts the rectified DC bus voltage to maintain stable inverter input. Check the PFC reactor and IGBT module on the inverter board. A failed PFC circuit often causes E302 or E316 as a secondary code.
E316 — DC Link Voltage Low (3-Phase Input)
On three-phase DVM S systems, the DC bus voltage is too low for inverter operation. Check all three phases for voltage and balance. A phase loss on 3-phase power drops the DC bus to approximately 60% of normal. Measure L1-L2, L2-L3, and L1-L3 at the outdoor unit disconnect. Any reading more than 2% below the others indicates a problem upstream.
Common causes: blown fuse on a single phase, loose lug in the disconnect, tripped breaker on one phase, or a failed contactor pole.
E321 — Compressor Overcurrent Protection
The compressor is drawing more current than the inverter allows. Measure running amps per phase with an amp clamp. Compare against the nameplate rated load amps (RLA). A compressor drawing 120% or more of RLA points to mechanical binding, overcharge, or failing bearings.
E4xx — Expansion Valve Faults
The DVM S uses a stepper motor EEV for refrigerant metering. The EEV coil drives the needle valve open and closed based on superheat target.
E401 — EEV Coil Open or Short
Measure coil resistance across the EEV connector pins. A good DVM S EEV coil reads between 50 and 100 ohms depending on the model. An open circuit indicates a broken coil winding. A short circuit means the coil insulation has failed.
Replace the EEV coil assembly only. Do not replace the entire valve body unless the needle or valve body is physically damaged.
E404 — EEV Operation Failure
The PCB commanded the EEV to move but did not receive confirmation through the feedback circuit. Remove and manually check the EEV coil. The coil should click audibly when pulsed with 12VDC. If the coil tests good, the valve body may be stuck from debris in the refrigerant system.
E5xx — Safety Protection Codes
These codes engage when system conditions exceed safety thresholds. The compressor shuts down and the code remains until manually reset by cycling power.
E501 — High Pressure Protection
The high-pressure transducer or pressure switch reading exceeded the trip point (approximately 590 psi for R-410A). Check the outdoor condenser fan first. A fan that runs slow or not at all pushes head pressure past the safety limit. Measure fan motor amp draw. A failing motor that draws less than nameplate FLA while running is running slow due to a bad capacitor or worn bearings.
If the fan checks out, wash the outdoor coil. Use a garden hose and spray from the inside out. A blocked coil raises condensing temperature and pressure.
E502 — Low Pressure Protection
Suction pressure dropped below the minimum operating range. Check indoor airflow: dirty filters, closed zone dampers, or a failing indoor fan motor can all pull suction pressure down. If airflow is correct, check for low refrigerant charge. Use Samsung’s charging chart in the outdoor unit panel door to verify subcooling at the liquid line service port.
A stuck EEV in the closed position causes the same code. Monitor EEV position through the system controller. A healthy DVM S EEV opens to 200 to 500 pulses during normal operation. An EEV stuck below 50 pulses means the valve or its driver has failed.
E504 — Discharge Temperature High
The compressor discharge temperature exceeded 230°F. This is a critical fault. Running a DVM S compressor above 230°F breaks down the refrigerant oil and damages internal components. Low refrigerant charge, a restricted EEV, or low outdoor airflow all cause high discharge temperature.
Check the liquid line sight glass for flashing refrigerant. Bubbles at the sight glass confirm low charge. Verify the EEV is operating by watching its position on the system controller.
E505 — Oil Return Fault
In heat recovery DVM S systems, oil return to the compressor is critical. Every outdoor module has an oil separator. If the oil return line is restricted or the oil separator has failed, the compressor runs low on oil and triggers E505.
Check the oil return line from the oil separator to the compressor suction line. The line must be warm during operation. A cold oil return line means the separator is blocked or the check valve has failed.
E508 — Condenser High Temperature
The outdoor coil sensor reading exceeds the safety limit. Same diagnostic path as E501. Clean the coil, check the fan, and verify the outdoor temperature sensor resistance.
When to Call a Professional
Samsung DVM S VRF systems are high-voltage, high-value equipment. Call a commercial HVAC technician for any of these situations:
- E302, E307, E312, or E316 inverter faults. The DC bus capacitors on the inverter board hold lethal charge for minutes after power is removed. Discharge them properly before testing.
- E504 discharge temperature faults. Running the compressor above 230°F in repeated diagnostic attempts can crack the scroll set and contaminate the system with metal debris.
- E505 oil return faults that do not clear after checking the oil return line. Oil management in heat recovery VRF systems requires manufacturer-specific service tools.
- Any code that returns immediately after cycling power. The Samsung DVM S service manual, SmartThings Pro diagnostic data, and NASA controller history are necessary for complex intermittent faults.
Frequently Asked Questions
Q: Where do I read the 3-digit error code on a DVM S system? It displays on the 7-segment LED on the outdoor unit main PCB. The code shows when the fault is active. Indoor unit remote controllers show C-series codes, not E-series codes.
Q: What is normal DC bus voltage on a DVM S outdoor unit? On a 208-240V input, expect 300-350 VDC. On a 460V input, expect 600-680 VDC. Measure between the positive and negative DC bus test points on the inverter board.
Q: Can a bad EEV coil cause the compressor to fault? Yes. An EEV that fails closed restricts refrigerant flow, which raises discharge temperature, drops suction pressure, and can trigger E504 or E502 as a secondary effect.
Q: Why does my DVM S system show E316 after a power outage? A phase loss or brownout condition on one leg of the 3-phase supply causes the DC bus voltage to drop. Check that all three phases came back with proper voltage and balance.
Q: Do I need Samsung service software to diagnose DVM S faults? No. The 7-segment code and basic electrical testing (voltage, resistance, amp draw) covers 80% of DVM S faults. SmartThings Pro helps with historical data and EEV position monitoring but is not required for initial diagnosis.