Worcester Bosch
Worcester Bosch Return Unit Hu1 No Bp Valve 87186838200
Worcester Bosch 87186838200 return unit (HU1, no bypass valve) for Greenstar combi and system boilers, managing water flow through the hydraulic block.
At a glance
- Part type: Diverter valves and hydraulics
- Also known as 1030813
- This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Showing prices
£140.71
£117.26 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 87186838200 is a return unit, listed by the manufacturer as HU1 and supplied without a bypass valve. It sits within the diverter valve and hydraulics group of the appliance, where it manages the flow of water through the hydraulic block so the boiler can move between domestic hot water and central heating duties. It is built for the Worcester Bosch Greenstar family of combi and system boilers.
Signs this part needs replacing
- Domestic hot water runs cold or only warms intermittently while the boiler is firing.
- Hot water temperature swings noticeably at the tap, or the boiler cycles in and out during a draw-off.
- The appliance does not switch cleanly between central heating and hot water, leaving one mode unresponsive.
- Radiators heat up when only hot water is being drawn, or hot water is produced when only heating is called for.
- Water weeps or drips from around the hydraulic assembly or the return unit body.
Before you order
- Check the GC number on the appliance data badge against the compatibility list to confirm the model.
- Confirm the part number currently fitted and cross-check it against the alternative number 1030813 before ordering.
- Inspect the surrounding seals and gaskets on removal, as these are commonly disturbed when the hydraulic assembly is opened.
- This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Mechanical
| Part type | Manifolds |
|---|---|
| Length | 0.1mm |
| Width | 0.1mm |
| Depth | 0.1mm |
Compliance
| Manufacturer part number (MPN) | 87186838200 |
|---|---|
| GC number | J04-467 |
| Barcode / EAN | 4051516197261 |
| Commodity code | 8403 90 00 00 |
| GPC classification | Household Boilers/Furnaces/Tank Water Heaters Replacement Parts/Accessories |
| Alternative numbers | 1030813 |
| 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 28 CDI COMPACT LPG | 47-406-45 | 47-406-45 | — | — |
| WORCESTER GREENSTAR 28 CDI COMPACT NG | 47-406-44 | 47-406-44 | — | — |
| WORCESTER GREENSTAR 28CDi ErP COMPACT LPG | 47-406-78 | 47-406-78 | — | — |
| WORCESTER GREENSTAR 28CDi ErP COMPACT NG | 47-406-77 | 47-406-77 | — | — |
| WORCESTER GREENSTAR 28Si ErP COMPACT | — | — | — | |
| WORCESTER GREENSTAR 30 SI COMPACT LPG | 47-406-53 | 47-406-53 | — | — |
Showing 10 of 46 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 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 HEATSLAVE II 12/18 ErP, GREENSTAR HEATSLAVE II 18/25 ErP, GREENSTAR HEATSLAVE II 25/32 ErP
manualmanualWORCESTER appliance manual — GREENSTAR HEATSLAVE II EXT 12/18 ErP, GREENSTAR HEATSLAVE II EXT 18/25 ErP, GREENSTAR HEATSLAVE II EXT 25/32 ErP
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