Alpha
Alpha by-pass complete cartridge 3.021689
Genuine Alpha automatic by-pass complete cartridge for the InTec boiler range, part number 3.021689.
At a glance
- Also known as 1258439
Showing prices
£43.37
£36.14 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 by-pass complete cartridge is the automatic by-pass valve cartridge that maintains minimum flow through the boiler when radiator valves close down. It is a genuine Alpha part, number 3.021689.
Signs this part needs replacing
- The valve or motor fails to switch between heating and hot water, or is slow and noisy in operation
- No hot water or no heating on one circuit while the other works normally
- The motor hums but does not turn, or the cartridge is seized, sticking or leaking
Before you order
- Isolate electrical power and drain down the relevant circuit before removing the valve or motor
- Confirm the fault is the motor or cartridge itself rather than the signal driving it
- Match the part number exactly, as these assemblies are often revised between production runs
Compliance
| Alternative numbers | BY-PASS-ASSEMBLY, 1258439 |
|---|
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| ALPHA ALPHA ECO | — | — | — | |
| ALPHA ALPHA ECO BOILER | — | — | — | |
| ALPHA ALPHA INTEC 12S | — | — | — | |
| ALPHA ALPHA INTEC 12S LPG | — | — | — | |
| ALPHA ALPHA INTEC 18S | — | — | — | |
| ALPHA ALPHA INTEC 18S LPG | — | — | — | |
| ALPHA ALPHA INTEC 24X | — | — | — | |
| ALPHA ALPHA INTEC 26C | — | — | — | |
| ALPHA ALPHA INTEC 26C LPG | — | — | — | |
| ALPHA ALPHA INTEC 28S | — | — | — |
Showing 10 of 94 compatible appliances.
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.
manual
ALPHA appliance manual — ALPHA ECO BOILER
manualmanualALPHA appliance manual — E-TEC 20NXS (GC 41-532-53), E-TEC 20NXS LPG (GC 41-532-53), E-TEC 30NXS (GC 41-532-54), E-TEC 30NXS LPG (GC 41-532-54), E-TEC 35NXS (GC 41-532-55), E-TEC 35NXS LPG (GC 41-532-55)
manualmanualALPHA appliance manual — E-TEC 20S (GC 41-532-47), E-TEC 20S (LPG), E-TEC 30S (GC 41-532-48), E-TEC 30S (LPG), E-TEC 35S (GC 41-532-52), E-TEC 35S (LPG) (GC 41-532-52)
manualmanualALPHA appliance manual — E-TEC 28 (GC 47-532-69), E-TEC 28 (LPG) (GC 47-532-73), E-TEC 33 (GC 47-532-70), E-TEC 33 (LPG) (GC 47-532-74)
manualmanualALPHA appliance manual — E-TEC 33NX (GC 47-532-82), E-TEC 33NX LPG (GC 47-532-83)
manualmanualALPHA appliance manual — E-TEC HYBRID 33HB
manualmanualALPHA appliance manual — E-TEC PLUS 28 (GC 47-532-77), E-TEC PLUS 28 (LPG) (GC 47-532-77), E-TEC PLUS 33 (GC 47-532-78), E-TEC PLUS 38 (GC 47-532-79), E-TEC PLUS 38 (LPG) (GC 47-532-79)
manualmanualALPHA appliance manual — E-TEC PLUS 28NX (GC 47-532-89), E-TEC PLUS 28NX LPG (GC 47-532-89), E-TEC PLUS 38NX (GC 47-532-91), E-TEC PLUS 38NX LPG (GC 47-532-91)
manualmanualALPHA appliance manual — EVOKE 28 (GC 47-532-71), EVOKE 28 (LPG) (GC 47-532-75), EVOKE 33 (GC 47-532-72), EVOKE 33 (LPG) (GC 47-532-76)
manualmanualALPHA appliance manual — EVOKE 28NX (GC 47-532-84), EVOKE 28NX LPG (GC 47-532-85), EVOKE 33NX (GC 47-532-86), EVOKE 33NX LPG (GC 47-532-87)
manualmanualALPHA appliance manual — INTEC 40GS2
manualmanualALPHA appliance manual — InTEC 12S (GC 41-532-22), InTEC 12S (LPG) (GC 41-532-25), InTEC 18S (GC 41-532-23), InTEC 18S (LPG) (GC 41-532-26), InTEC 28S (GC 41-532-24), InTEC 28S (LPG) (GC 41-532-27)
manualmanualALPHA appliance manual — InTEC 24X (GC 47-532-45), InTEC 24X (LPG) (GC 47-532-52), InTEC 26C (GC 47-532-47), InTEC 26C (LPG) (GC 47-532-54), InTEC 28X (GC 47-532-46), InTEC 28X (LPG) (GC 47-532-53), InTEC 30C (GC 47-532-48), InTEC 30C (LPG) (GC 47-532-55), InTEC 34C (GC 47-532-49), InTEC 34C (LPG) (GC 47-532-56)
manualmanualALPHA appliance manual — InTEC 30C ErP (GC 47-532-48), InTEC 30C ErP (LPG) (GC 47-532-55), InTEC 34C ErP (GC 47-532-49), InTEC 34C ErP (LPG) (GC 47-532-56)
manualmanualALPHA appliance manual — InTEC 30GS (GC 47-532-50), InTEC 30GS (LPG) (GC 47-532-57), InTEC 40GS (GC 47-532-51), InTEC 40GS (LPG) (GC 47-532-58)
manualmanualALPHA appliance manual — InTEC 30GS ErP (GC 47-532-50), InTEC 30GS ErP (LPG) (GC 47-532-57), InTEC 40GS ErP (GC 47-532-51), InTEC 40GS ErP (LPG) (GC 47-532-58)
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