Horstmann Controls
Horstmann 425 Tiara programmer
Horstmann 425 Tiara two-circuit mechanical central heating and hot water programmer, part number NU0550301000, now discontinued.
At a glance
- Also known as 4210005
£114.42
£95.35 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 425 Tiara is a mechanical, two-circuit programmer from Horstmann for central heating and hot water, using a 24-hour rotating dial with red and blue pins to set on/off periods.
Signs this part needs replacing
- Dial no longer holds its position or advances on its own
- Heating or hot water fails to switch on/off at the set times
- Advance switch fails to override the programme
- Visible wear or damage to the dial pins
Before you order
- Match the part number printed on your existing programmer
- Isolate electrical power before replacing
- Note this model is discontinued; check the 9-pin wall plate matches before ordering a replacement
Compliance
| Barcode / EAN | 5015914553011 |
|---|---|
| Alternative numbers | 4210005 |
No fitment data held for this part.
Documents & drawings
Everything we hold for this part. Where a document exists but we don't hold it, the technical team will source it from the manufacturer — usually the same working day.
No documents held for this part. The technical team will source them from the manufacturer — usually the same working day.
No technical questions yet for this part.
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