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Worcester Greenstar 4000 System Boiler 12-24kW | GR4700iW S
Regular price
$2,250.00
Inc. VAT
$1,875.00
Exc. VAT
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The Worcester Greenstar 4000 System Boiler is a wall-hung, gas-fired condensing system boiler for homes that heat their water through a stored hot water cylinder. It is supplied in 12kW, 15kW, 18kW, 21kW and 24kW natural gas outputs (GR4700iW S), and every model shares the same 724 x 400 x 310mm casing, an ErP A energy efficiency class and a 94% seasonal space heating efficiency.
The key system components are built in: a low energy modulating pump, expansion vessel, pressure relief valve, digital pressure sensor and automatic air vent. A full-text colour display makes status and fault information easy to read, front access to all key components speeds up servicing, and the range is Quiet Mark certified across all five outputs.
Designed for small to medium homes, the Greenstar 4000 System is also built to replace older boilers quickly: SimpleSwitch compatibility with Greenstar i System wall-frame fixings and PRV pipework, a pre-piping jig and rear piping as standard, and flue runs of up to 16m (60/100) give installers real flexibility on site.
5
outputs, 12 to 24kW
A / 94%
ErP class and seasonal efficiency
30.6kg
lift weight, all models
724x400x310
mm, height x width x depth
16m
max 60/100 flue (12 and 15kW)
7 years
standard guarantee
Installation and safety
This appliance must be installed, commissioned and serviced by a competent Gas Safe registered engineer in line with the Gas Safety (Installation and Use) Regulations. Use only Worcester Condensfit II flue systems, fit a carbon monoxide alarm, complete the Benchmark commissioning checklist and have the boiler and system serviced annually.Hot water cylinder required
This is a system boiler, so it does not produce hot water on demand. A separate hot water cylinder is needed, and the boiler is designed for sealed systems only. Worcester programmers and smart controls are specified for use with the optional integral diverter valve kit (7 733 601 251). For unvented cylinders, confirm suitability with the cylinder manufacturer.System preparation
Flush and inhibit the primary circuit to BS 7593 and fit a system filter that removes magnetite and non-magnetic debris. Salt-based softened water must not be used to fill the heating system. Extended guarantees are not available when a System Filter Micro is fitted.Natural gas models
The part numbers on this page are the natural gas (NG) models. LPG versions of the range are sold under separate part numbers (7 733 600 378, 380, 382, 384 and 386), so please contact us before ordering for an LPG installation.Key features
Compact, uniform footprint
All five outputs share a 724 x 400 x 310mm casing and a 30.6kg lift weight, so one cupboard or kitchen position suits every size in the range.
SimpleSwitch replacement
Wall-frame fixings align with Greenstar i System boilers, the PRV connector rotates approx. 45 degrees to meet existing pipework, and a SimpleSwitch flue adaptor reuses the existing 60/100 flue hole.
Wide modulation
Zero pressure governor gas valve with a fully modulating fan and a modulation ratio of up to 1:8, matching output to demand and reducing gas use.
Easy servicing
Front access to all key components, including the PRV, an inspection and heat exchanger cleaning aperture and a large volume siphonic condensate trap that lowers the risk of condensate pipe freezing.
Quiet Mark certified
Rated by Quiet Mark across all five outputs, with ErP sound power levels of 43 to 45 dB on the 15, 18 and 21kW models.
Control and flue flexibility
Works with Bosch EasyControl, Sense and Comfort+ controls, weather compensation, and Condensfit II 60/100 and 80/125 flues with plume management up to 4.5m.
Choose your output
Select the output that matches a room-by-room heat loss calculation for the property. The 12kW and 15kW models modulate down to 1.9kW and allow the longest 60/100 flue (16m), while the 18kW, 21kW and 24kW models modulate down to 3kW.
Output
Part number (MPN)
CH output range
Gas Council no.
Max flue 60/100
Max flue 80/125
12kW
7733600377
1.9 to 12kW
41-800-07
16m
20m
15kW
7733600379
1.9 to 15kW
41-800-09
16m
20m
18kW
7733600381
3 to 18kW
41-800-11
12m
21m
21kW
7733600383
3 to 21kW
41-800-13
12m
21m
24kW
7733600385
3 to 24kW
41-800-15
12m
21m
Technical specification
Frequently asked questions
BTU & WATT Calculator
Room Dimensions
Room Type
Living Room
Bedroom
Kitchen
Bathroom
Conservatory
Hallway
Glazing Type
Single Glazed
Double Glazed
Triple Glazed
External Walls
0 Wall
1 Wall
2 Walls
3 Walls
4 Walls
Insulation Level
Poor
Average
Good (New Build)
Required Heating
0
Watts
0
BTUs
Tools & Kits
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about this product?
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