Worcester Bosch
Worcester Bosch Pipe Restrictor Bypass 87186858740
Worcester Bosch pipe restrictor bypass (87186858740) for Greenstar i and i System boilers, part of the internal pipework and bypass circuit.
At a glance
- Part type: Pipes & Hoses
- Also known as 1030801
- This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Showing prices
£4.38
£3.65 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 pipe restrictor bypass, part number 87186858740, is a small internal pipework component used in the bypass circuit of Worcester Bosch gas boilers. It sits within the appliance's internal pipe run and controls the flow of water around the bypass loop, which keeps a minimum circulation rate through the heat exchanger when system demand falls. It is a Worcester Bosch spare and is listed under the pipes and hoses group of the internal assembly.
Signs this part needs replacing
- Boiler short-cycling or failing to hold a steady flow temperature when heating demand drops
- Overheating or a high-limit trip caused by insufficient flow through the bypass circuit
- Kettling, banging or rushing water noise from the heat exchanger area
- Visible scale, sludge or debris blocking the restrictor, or a restrictor that has been removed or lost during previous work
- Weeping or damp staining at the pipe joint where the restrictor sits
Before you order
- Check the appliance GC number or serial plate against the compatibility list to confirm the correct variant for your boiler
- Confirm the existing part number and the alternative number 1030801 before ordering
- Inspect the surrounding seals and pipe connections and renew any that are disturbed during the repair
- This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Mechanical
| Part type | Pipes & Hoses |
|---|---|
| Length | 0.1mm |
| Width | 0.1mm |
| Depth | 0.1mm |
Compliance
| Manufacturer part number (MPN) | 87186858740 |
|---|---|
| GC number | J03-524 |
| Barcode / EAN | 4051516265656 |
| Commodity code | 8403 90 00 00 |
| GPC classification | Household Boilers/Furnaces/Tank Water Heaters Replacement Parts/Accessories |
| Alternative numbers | 1030801 |
| Make | Model / assembly | Reference | Years | Fitment |
|---|---|---|---|---|
| WORCESTER GREENSTAR 12i ErP SYSTEM LPG | 41-406-24 | 41-406-24 | — | — |
| WORCESTER GREENSTAR 12i ErP SYSTEM NG | 41-406-23 | 41-406-23 | — | — |
| WORCESTER GREENSTAR 12i SYSTEM LPG | 41-311-69 | 41-311-69 | — | — |
| WORCESTER GREENSTAR 12i SYSTEM NG | 41-311-67 | 41-311-67 | — | — |
| WORCESTER GREENSTAR 15I SYSTEM LPG | 41-406-26 | 41-406-26 | — | — |
| WORCESTER GREENSTAR 15I SYSTEM NG | 41-311-84 | 41-311-84 | — | — |
| WORCESTER GREENSTAR 15i ErP SYSTEM LPG | 41-406-26 | 41-406-26 | — | — |
| WORCESTER GREENSTAR 15i ErP SYSTEM NG | 41-406-25 | 41-406-25 | — | — |
| WORCESTER GREENSTAR 18I SYSTEM LPG | 41-311-87 | 41-311-87 | — | — |
| WORCESTER GREENSTAR 18I SYSTEM NG | 41-311-86 | 41-311-86 | — | — |
Showing 10 of 113 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 12i ErP SYSTEM LPG (GC 41-406-24), GREENSTAR 12i ErP SYSTEM NG (GC 41-406-23), GREENSTAR 15i ErP SYSTEM LPG (GC 41-406-26), GREENSTAR 15i ErP SYSTEM NG (GC 41-406-25), GREENSTAR 18i ErP SYSTEM LPG (GC 41-406-28), GREENSTAR 18i ErP SYSTEM NG (GC 41-406-27), GREENSTAR 21i ErP SYSTEM LPG (GC 41-406-30), GREENSTAR 21i ErP SYSTEM NG (GC 41-406-29), GREENSTAR 24i ErP SYSTEM LPG (GC 41-406-32), GREENSTAR 24i ErP SYSTEM NG (GC 41-406-31), GREENSTAR 9i ErP SYSTEM LPG (GC 41-406-22), GREENSTAR 9i ErP SYSTEM NG (GC 41-406-21)
manualmanualWORCESTER appliance manual — GREENSTAR 12i SYSTEM LPG (GC 41-311-69), GREENSTAR 12i SYSTEM NG (GC 41-311-67), GREENSTAR 15I SYSTEM LPG (GC 41-406-26), GREENSTAR 15I SYSTEM NG (GC 41-311-84), GREENSTAR 18I SYSTEM LPG (GC 41-311-87), GREENSTAR 18I SYSTEM NG (GC 41-311-86), GREENSTAR 24i SYSTEM LPG (GC 41-311-70), GREENSTAR 24i SYSTEM NG (GC 41-311-68)
manualmanualWORCESTER appliance manual — GREENSTAR 24I JUNIOR MK5 LPG (GC 47-406-55), GREENSTAR 24I JUNIOR MK5 NG (GC 47-406-54), GREENSTAR 24I JUNIOR NG (GC 47-311-86), GREENSTAR 24i JUNIOR LPG (GC 47-311-90), GREENSTAR 28I JUNIOR MK5 LPG (GC 47-406-57), GREENSTAR 28I JUNIOR MK5 NG (GC 47-406-56), GREENSTAR 28i JUNIOR LPG (GC 47-311-91), GREENSTAR 28i JUNIOR NG (GC 47-311-87)
manualmanualWORCESTER appliance manual — GREENSTAR 25SI COMBI LPG (GC 47-311-88), GREENSTAR 25SI COMBI NG (GC 47-311-84), GREENSTAR 30 SI COMBI LPG (GC 47-311-89), GREENSTAR 30 SI COMBI NG (GC 47-311-85)
manualmanualWORCESTER 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 25i ErP COMBI LPG (GC 47-406-61), GREENSTAR 25i ErP COMBI NG (GC 47-406-60), GREENSTAR 30i ErP COMBI LPG (GC 47-406-63), GREENSTAR 30i ErP COMBI NG (GC 47-406-62)
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 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)
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