Ariston - Protherm Combi Boiler 3-Way Valve Motor Connection Cable 50 cm, 3-Pin Connector – Compatible with 65104523 / 0020034153

This is a 50 cm ready-made cable that provides the connection between the boiler's main board and the 3-way valve motor (diverter valve actuator). At one end there is a 3-pin straight female connector that plugs into the valve motor, and at the other end 3 wires with open (stripped) ends for connection: red, white and black. In manufacturer catalogs it is listed under the codes Ariston 65104523 and Protherm 0020034153.

Because the cable passes through the hottest and most vibration-prone area of the boiler, its insulation hardens over time, its wires break or the connector terminals oxidize. In this case, even if the valve motor itself is sound, the control signal does not reach it.

Compatible Combi Boiler Models

This cable replaces the 3-way valve motor cable used in the appliances below. The manufacturer has produced the part to replace both the Ariston 65104523 and the Protherm 0020034153 coded cables. The two codes belong to different manufacturer groups; what they have in common is the 3-pin straight socket geometry on the valve motor. Therefore, before ordering, compare the socket on your own appliance with the one in the photo.

Is the Cable or the Valve Motor Faulty?

When the 3-way valve control is lost, the fault can be in three places: in the board, in the cable or in the motor. The sequence for telling them apart in the field is as follows:

• Measure the voltage at the valve motor socket. While hot water is demanded (with the tap open), 230 V or 24 V, depending on the appliance type, should be read at the socket. If there is voltage, the cable is sound and the fault is in the valve motor. If there is no voltage, move the measurement toward the board.
• Measure at the board output. If there is voltage at the board output but it does not reach the socket, the fault is in the cable. If there is no voltage at the board output either, the fault is in the board's relay, and replacing the cable will not solve it.
• Inspect the connector visually. If there is blackening, green corrosion or melting on the pin terminals, the cable is replaced; even if an oxidized terminal is cleaned, contact deteriorates again within a short time.
• Measure the cable in continuity (ohm) mode. The resistance between each wire's connector pin and its open end should be almost zero. If there is no continuity on a wire, the cable is broken inside.
• Measure while moving the cable. If the valve switches on and off when the cable is moved by hand while the boiler is running, the break is under the insulation and is not visible.
• Check whether there is a short circuit between wires. If continuity is read between two wires, the insulation has melted; since this can also damage the board, the cable is replaced immediately.
• If the cable is sound, the control voltage at the board output is measured; if voltage is present, the fault is in the valve motor.

Fault Symptoms

• The boiler does not switch to hot water, or conversely, does not return to the radiators even though the tap is closed.
• The valve does not change position — the motor makes no sound at all.
• The boiler runs and stops intermittently; the valve engages occasionally (intermittent contact inside the cable).
• Burn/soot marks on the board or connector — the wire contact may have deteriorated and arced.

Technical Specifications

• Part Type: 3-way valve motor connection cable
• Length: 50 cm
• Number of Wires: 3 (red · white · black)
• Connector: 3-pin straight female socket (valve motor side)
• Other End: Open, stripped ends
• Corresponding Codes: Ariston 65104523 · Protherm 0020034153

Installation Notes

• Before replacement, the boiler's power is switched off.
• The wire colors and connection order of the removed cable are noted; the new cable is connected in the same arrangement. If the color order is changed, the valve runs in the reverse direction or does not run at all.
• When connecting the open ends to the board or terminal block, the wire ends are twisted neatly, and ferrules are used if necessary; stray strands can touch the neighboring terminal and cause a short circuit.
• The cable is routed away from hot surfaces such as the burner and heat exchanger and seated in its original clips.
• The connector is pushed onto the valve motor until it clicks; a half-seated socket will arc over time.