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Saunier Duval Diverter Valve S1020800

Saunier Duval

Saunier Duval Diverter Valve S1020800

Three-way diverter valve for Saunier Duval Themaclassic gas boilers, part number S1020800.

At a glance

  • Also known as 1416185, N3165-1
  • If unsure, consult a Gas Safe registered engineer
Manufacturer part no.
S1020800
Showing prices

£254.94

£212.45 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 Saunier Duval S1020800 is a three-way diverter valve used in Themaclassic gas boilers. It directs water flow between the central heating circuit and the domestic hot water circuit. This valve replaces the earlier code 1020800.

Signs this part needs replacing

  • No hot water when a tap is opened
  • Heating circuit warms up when only hot water is demanded
  • Domestic hot water runs lukewarm or fluctuates
  • Diverter valve stuck in one position
  • Boiler displays a fault code related to diverter valve operation

Before you order

  • Check your boiler model and GC number against the fitment list
  • Confirm the part number S1020800 matches the valve being replaced
  • Inspect the valve and surrounding pipework for scale or debris
  • If unsure, consult a Gas Safe registered engineer

Not sure which part?

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