What Does Error Code AC2 Mean on a Samsung Washing Machine?
Switch the hot and cold water inlet hoses on the back of the machine so the hot hose connects to the hot inlet (marked H or red) and the cold hose to the cold inlet (marked C or blue), then restart the cycle (takes about 10 minutes).
Fault description
Error code AC2 is Samsung's way of telling you that the water supply hoses feeding your washing machine have been connected the wrong way around. The machine detects that water entering through the cold inlet is warmer than expected — or vice versa — and stops the cycle to prevent damage to fabrics or internal components.
This error most commonly appears after a new installation, after the machine has been moved, or following plumbing work in the home. It is not a sign of a mechanical fault inside the machine itself. The washing machine's inlet valves and temperature sensors are working exactly as they should — they have simply detected an inconsistency between the expected and actual water temperatures at each inlet.
The good news is that AC2 is one of the most straightforward errors to resolve. No parts need replacing and no tools are usually required beyond turning off the water supply. Most homeowners can clear this fault in under fifteen minutes.
Causes
- Hot and cold hoses connected in reverse — This is the primary and most common cause of AC2. During installation or after moving the machine, the red (hot) hose is connected to the cold inlet and the blue (cold) hose to the hot inlet, which the machine's temperature sensor immediately detects as incorrect.
- Hoses reconnected incorrectly after plumbing work — If a plumber has recently worked on your water supply or the machine was disconnected and reconnected, the hoses may have been reattached without checking which inlet is which. Even experienced plumbers occasionally swap these connections on unfamiliar machines.
- Unmarked or faded inlet labels on older machines — On older Samsung models, the H (hot) and C (cold) markings on the back panel can fade or become obscured by limescale and grime. This makes it easy to connect hoses to the wrong inlets without realising.
- Non-standard household plumbing layout — In some older properties, hot and cold supply pipes are not positioned in the conventional left-hot, right-cold arrangement. If the machine was installed without checking the actual pipe temperatures, the hoses may have been connected based on position rather than function.
- Hoses without clear colour coding — Replacement hoses that are a single colour — typically grey or black — can be connected to the wrong inlets simply because there is no visual cue to distinguish them. Without checking the inlet labels carefully, it is easy to make this mistake.
Step-by-Step Fix
- 1
Turn off the water supply
Locate the hot and cold isolation valves behind or beneath the machine and turn them off. If there are no individual valves, turn off the mains water supply to the house. This prevents any water escaping when you disconnect the hoses.
- 2
Pull the machine away from the wall
Carefully slide the washing machine forward so you have clear access to the hose connections at the back. Ask someone to help if the machine is heavy. Lay an old towel on the floor to catch any residual water in the hoses.
- 3
Identify the hot and cold inlets on the machine
Look at the back panel of the machine for the inlet labels. On most Samsung models, the hot inlet is marked with an H or a red indicator, and the cold inlet is marked with a C or a blue indicator. Take a photo before disconnecting anything so you have a reference.
- 4
Disconnect both hoses
Unscrew each hose by hand or with a pair of pliers if they are tight. Have a small bowl or towel ready to catch the water that will drain from the hoses. Keep track of which hose came from which household supply pipe — hot or cold.
- 5
Reconnect the hoses correctly
Attach the hose from your hot water supply pipe to the H (hot) inlet on the machine, and the hose from your cold supply to the C (cold) inlet. Hand-tighten firmly, then give each connection a quarter-turn with pliers to ensure a watertight seal. Do not overtighten, as this can damage the rubber washers.
- 6
Turn the water back on and check for leaks
Slowly reopen the isolation valves and inspect both hose connections for drips. If you see any leaking, turn the water off again and check that the rubber washers inside the hose fittings are seated correctly before retightening.
- 7
Run a short test cycle and confirm the error has cleared
Push the machine back into position, select a short wash cycle, and start the machine. The AC2 error should no longer appear. If it does, double-check that your household hot supply pipe is actually delivering hot water — run a nearby tap to confirm.
Affected models
Select your model to see its full troubleshooting page.
When to call a service technician
If you have correctly swapped the hoses and confirmed that your household hot water supply is genuinely delivering hot water, but the AC2 error continues to appear, there may be a fault with the machine's water temperature sensor (NTC thermistor) or the main control board. These components require testing with a multimeter and, in most cases, replacement by a qualified service technician.
You should also contact a service technician if you notice any signs of water damage around the inlet valve area, if the hose connections feel loose or the threads appear stripped, or if the machine is still under warranty and you would prefer not to carry out any work yourself that could affect the warranty terms.
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Frequently Asked Questions
Will error code AC2 damage my Samsung washing machine?
AC2 itself does not cause damage — the machine stops the cycle as a precaution before any harm can occur. However, if the error is ignored and the machine is repeatedly forced to run with reversed hoses, there is a risk of washing clothes at the wrong temperature or stressing the inlet valves over time. Fixing it promptly is always the right approach.
My hoses look like they are connected correctly but AC2 still shows. Why?
First, confirm that your hot water supply pipe is actually delivering hot water by running a nearby tap or sink. In some homes, the hot supply can be slow to heat up or may have been turned off at the boiler. If the hot supply is confirmed working and the hoses are correctly connected, the fault may lie with the temperature sensor or control board, which will need a service technician to diagnose.
Does AC2 appear on all Samsung washing machine models?
AC2 is present on a wide range of Samsung washing machines, including older top-loader and front-loader models as well as newer FlexWash machines. The models most commonly associated with this code include the B1253, F1045, J1466, J1488, and the FlexWash WV60M9900AV, among others. The fix is the same across all affected models.
Can I run a cold-only wash to get around the AC2 error temporarily?
Some users find that selecting a cold wash programme clears the error temporarily, since the machine does not need to draw on the hot inlet. However, this is not a reliable workaround and the error will likely return when a warm or hot wash is selected. Swapping the hoses is the only permanent solution.
How do I know which pipe in my home is the hot supply and which is cold?
The simplest way is to run a nearby tap — such as the kitchen or utility room sink — and feel which pipe becomes warm after a minute or so. Hot supply pipes are often insulated with foam lagging. If you are still unsure, a plumber can confirm the layout of your supply pipes quickly and at low cost.