Horstmann Controls
Horstmann Z322 22mm 3 port mid-position valve
Horstmann's 22mm 3 port motorised mid-position valve for Y-plan fully pumped heating and hot water systems.
At a glance
- Also known as 4210125
£117.17
£97.64 ex. VAT · VAT at 20%
Same-day dispatch
Ordered by 4pm Mon–Fri, 10:30am Sat.
30-day returns
Unused, in original packaging.
What it is
The Horstmann Z322 (current designation Z322XL) is a 3 port motorised mid-position diverter valve for fully pumped central heating and hot water systems that share a single pump. It diverts flow from the boiler to the heating circuit, the hot water circuit, or both simultaneously, and operates the boiler and pump whenever either circuit calls for heat. It consists of a valve body (B322XL) with a separate, self-contained actuator (A322XL).
Signs this part needs replacing
- Radiators or hot water fail to heat independently (valve stuck mid-position)
- Actuator motor buzzing, overheating, or not moving between positions
- Valve fails to spring-return to hot-water-only on power loss
- Leaking at the valve body or compression joints
Before you order
- Confirm this is a 3 port mid-position valve, not a 2 port zone valve
- Isolate the mains electrical supply before disconnecting or replacing
- Drain and refill/flush the system after fitting, and check port operation as described in the manufacturer's commissioning procedure
- Fit by a competent heating engineer
Compliance
| Barcode / EAN | 5015914165016 |
|---|---|
| Alternative numbers | 4210125 |
No fitment data held for this part.
Documents & drawings
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No documents held for this part. The technical team will source them from the manufacturer — usually the same working day.
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