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Ariston 3 Port Valve Kit 573603

Ariston

Ariston 3 Port Valve Kit 573603

Three-port diverter valve repair kit for Ariston STYX SX 20 M and STYX SX 20 MFF boilers from serial number 92010000.

At a glance

  • Appliance family: STYX SX
  • Also known as KIT-FOR-THREE-PORT-VALVE, 1571024
Manufacturer part no.
573603
Showing prices

£38.84

£32.37 ex. VAT · VAT at 20%

Available to order · 3 working days
Available to order · 3 working days
Not certain it's the right part? The technical team verifies fitment before dispatch — no charge, and it stops a second trip.Call the technical teamSend a technical question

Same-day dispatch

Ordered by 4pm Mon–Fri, 10:30am Sat.

30-day returns

Unused, in original packaging.

What it is

The Ariston 573603 is a three-port valve kit for Ariston STYX SX boilers, supplied as a diverter valve repair kit. It restores the valve that switches the boiler between domestic hot water and central heating. The kit is intended for STYX SX 20 M and STYX SX 20 MFF models built from serial number 92010000 onwards.

Signs this part needs replacing

  • Hot water runs cold or fluctuates in temperature while the boiler is otherwise firing
  • Radiators warm up when only hot water is demanded, or hot water runs when only heating is demanded
  • The valve sticks and the boiler fails to switch cleanly between heating and hot water
  • Water weeps from the valve body or spindle
  • The boiler locks out or flags a fault when changing between heating and hot water modes

Before you order

  • Confirm the boiler model is STYX SX 20 M or STYX SX 20 MFF
  • Check the boiler serial number is 92010000 or later
  • Inspect the existing valve to confirm a repair kit is suitable rather than a complete valve assembly
  • Quote part number 573603 when ordering

Not sure which part?

Search by part number, product name or brand — our technical team confirms fitment before anything is dispatched.