Worcester Bosch
Worcester Bosch Seal Siphon 87186847420
Worcester Bosch seal siphon (87186847420) for Greenstar Compact boilers, forming an airtight joint in the condensate siphon assembly.
At a glance
- Part type: Gaskets, seals and washers
- Also known as 1030863
- This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Showing prices
£5.48
£4.57 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 Worcester Bosch 87186847420 is a seal siphon component for the condensate siphon assembly on Worcester Bosch Greenstar boilers. It forms a secure, airtight joint within the siphon body, keeping condensate contained and preventing water from escaping into the appliance casing. It is a service part for the Greenstar Compact range and related models.
Signs this part needs replacing
- Water weeping or dripping from the siphon or condensate trap area
- The seal looks cracked, flattened or hardened when the siphon is opened
- Damp staining or water pooling inside the casing beneath the siphon
- Leaks that return after the siphon has been stripped and rebuilt
- The joint around the siphon body no longer holds an airtight seal
Before you order
- Check the GC number on the appliance data badge against the compatibility list before ordering.
- Confirm the exact model and serial number, as this part number is shared across several Greenstar variants.
- The alternative number 1030863 may be listed for the same component by some suppliers.
- This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Mechanical
| Part type | Gaskets, Seals & Washers |
|---|---|
| Length | 0.1mm |
| Width | 0.1mm |
| Depth | 0.1mm |
Compliance
| Manufacturer part number (MPN) | 87186847420 |
|---|---|
| GC number | J04-370 |
| Barcode / EAN | 4051516200756 |
| Commodity code | 4016 93 00 00 |
| GPC classification | Household Boilers/Furnaces/Tank Water Heaters Replacement Parts/Accessories |
| Alternative numbers | 1030863 |
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| WORCESTER GREENSTAR 25SI COMPACT LPG | 47-406-51 | 47-406-51 | — | — |
| WORCESTER GREENSTAR 25SI COMPACT NG | 47-406-50 | 47-406-50 | — | — |
| WORCESTER GREENSTAR 25Si ErP COMPACT LPG | 47-407-74 | 47-407-74 | — | — |
| WORCESTER GREENSTAR 25Si ErP COMPACT NG | 47-406-73 | 47-406-73 | — | — |
| WORCESTER GREENSTAR 27I COMPACT SYSTEM LPG | 41-406-14 | 41-406-14 | — | — |
| WORCESTER GREENSTAR 27I COMPACT SYSTEM NG | 41-406-13 | 41-406-13 | — | — |
| WORCESTER GREENSTAR 27Ri ErP COMPACT LPG | 41-406-55 | 41-406-55 | — | — |
| WORCESTER GREENSTAR 27Ri ErP COMPACT NG | 41-406-54 | 41-406-54 | — | — |
| WORCESTER GREENSTAR 27i ErP SYSTEM COMPACT LPG | 41-406-59 | 41-406-59 | — | — |
| WORCESTER GREENSTAR 27i ErP SYSTEM COMPACT NG | 41-406-58 | 41-406-58 | — | — |
Showing 10 of 71 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
WORCESTER appliance manual — GREENSTAR 25SI COMPACT LPG (GC 47-406-51), GREENSTAR 25SI COMPACT NG (GC 47-406-50), GREENSTAR 30 SI COMPACT LPG (GC 47-406-53), GREENSTAR 30 SI COMPACT NG (GC 47-406-52)
manualmanualWORCESTER appliance manual — GREENSTAR 25Si ErP COMPACT LPG (GC 47-407-74), GREENSTAR 25Si ErP COMPACT NG (GC 47-406-73), GREENSTAR 28Si ErP COMPACT, GREENSTAR 30Si ErP COMPACT LPG (GC 47-406-76), GREENSTAR 30Si ErP COMPACT NG (GC 47-406-75)
manualmanualWORCESTER appliance manual — GREENSTAR 27I COMPACT SYSTEM LPG (GC 41-406-14), GREENSTAR 27I COMPACT SYSTEM NG (GC 41-406-13), GREENSTAR 30I COMPACT SYSTEM LPG (GC 41-406-16), GREENSTAR 30I COMPACT SYSTEM NG (GC 41-406-15)
manualmanualWORCESTER appliance manual — GREENSTAR 27Ri ErP COMPACT LPG (GC 41-406-55), GREENSTAR 27Ri ErP COMPACT NG (GC 41-406-54), GREENSTAR 30Ri ErP COMPACT LPG (GC 41-406-57), GREENSTAR 30Ri ErP COMPACT NG (GC 41-406-56)
manualmanualWORCESTER appliance manual — GREENSTAR 27i ErP SYSTEM COMPACT LPG (GC 41-406-59), GREENSTAR 27i ErP SYSTEM COMPACT NG (GC 41-406-58), GREENSTAR 30i ErP SYSTEM COMPACT LPG (GC 41-406-61), GREENSTAR 30i ErP SYSTEM COMPACT NG (GC 41-406-60)
manualmanualWORCESTER appliance manual — GREENSTAR 28 CDI COMPACT LPG (GC 47-406-45), GREENSTAR 28 CDI COMPACT NG (GC 47-406-44)
manualmanualWORCESTER appliance manual — GREENSTAR 28CDi ErP COMPACT LPG (GC 47-406-78), GREENSTAR 28CDi ErP COMPACT NG (GC 47-406-77), GREENSTAR 32CDi ErP COMPACT LPG (GC 47-406-80), GREENSTAR 32CDi ErP COMPACT NG (GC 47-406-79), GREENSTAR 36CDi ErP COMPACT LPG (GC 47-406-82), GREENSTAR 36CDi ErP COMPACT NG (GC 47-406-81)
manualmanualWORCESTER appliance manual — GREENSTAR 32CDI COMPACT LPG (GC 47-406-47), GREENSTAR 32CDI COMPACT NG (GC 47-406-46), GREENSTAR 36CDI COMPACT LPG (GC 47-406-49), GREENSTAR 36CDI COMPACT NG (GC 47-406-48)
manualmanualWORCESTER appliance manual — GREENSTAR RI 27KW COMPACT LPG (GC 41-406-18), GREENSTAR RI 27KW COMPACT NG (GC 41-406-17), GREENSTAR Ri 30KW COMPACT LPG (GC 41-406-20), GREENSTAR Ri 30KW COMPACT NG (GC 41-406-19)
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