Alpha
Alpha Check Valve 1.8251
Check valve for Alpha CB50, CD50 and InTEC 50CS gas boilers, part number 1.8251.
At a glance
- Also known as CHECK-VALVE-CB50, 1250427
Showing prices
£20.48
£17.07 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 Alpha 1.8251 is a check valve used in Alpha gas boilers. It is fitted in the appliance water circuit and allows flow in one direction only, preventing backflow. It is listed for the Alpha CB50, CD50 and InTEC 50CS models.
Signs this part needs replacing
- Water passing in the wrong direction through the valve
- Repeated pressure loss in the heating or hot water circuit
- Valve failing to seat and allowing backflow
- Scale or debris preventing the valve from closing
- Noise or vibration from the valve area
Before you order
- Confirm your boiler model matches one of the appliances listed above
- Check the existing valve against part number 1.8251
- For LPG appliances, confirm the boiler variant before ordering
- Isolate the appliance and depressurise before removing the old valve
Compliance
| GC number | E85-136 |
|---|---|
| Alternative numbers | CHECK-VALVE-CB50, 18251, 1250427 |
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| ALPHA ALPHA CB50 | — | — | — | |
| ALPHA ALPHA CD50 | — | — | — | |
| ALPHA ALPHA InTEC 50CS | — | — | — | |
| ALPHA CB50 | 47-532-18 | 47-532-18 | — | — |
| ALPHA CB50 (LPG) | — | — | — | |
| ALPHA CD50 | 47-532-24 | 47-532-24 | — | — |
| ALPHA CD50 (LPG) | — | — | — | |
| ALPHA InTEC 50CS | — | — | — |
Fitment listings are a guide, not a guarantee. Plant-room assemblies get modified on site more often than not. Send us the GC number off the data badge and a photo of the existing valve and we will confirm before anything is dispatched.
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 technical questions yet for this part.
Not sure which part?
Search by part number, product name or brand — our technical team confirms fitment before anything is dispatched.