Technical data

The Worcester Greenstar CDi Conventional is a wall-
mounted, gas-fired condensing ‘heating only’ or regular
boiler. The appliance combines, within one casing, a
cast-aluminium heat exchanger, fan, gas valve and other
electronic and mechanical equipment necessary to provide
central heating.
It is particularly suited to an older system which may not
sustain the higher pressures a system or combi boiler
operates under. With a feed and expansion cistern in the
roof space, any ‘topping up’ of the system is automatic,
unlike a sealed system which requires manual filling.
The Greenstar 30CDi System boiler is a compact and highly
efficient unit giving all the heating and hot water required,
with significant savings on running and installation costs.
The Greenstar 30CDi System boiler incorporates all the
major components built-in, including an expansion vessel
and modulating pump. All components are pre-wired, pre-
plumbed and pre-tested for greater reliability as well as
quicker and neater installation.
A condensing boiler is more efficient due to its ability to
extract more heat from the flue gases normally lost to the
environment through the flue system.
All the Greenstar CDi models use the same Aluminium-
Silicon heat cell with an extra large surface area.
As the flue gases pass through the heat exchanger this extra
surface area cools the flue gases to around 55°C
whereupon the latent heat within, which would normally be
lost to the atmosphere, is instead released and applied to
the system.
It is this ability to extract as much heat as possible from the
gas it burns that gives the Greenstar CDi series an
exceptionally high level of operating efficiency.
This higher efficiency is recognised within section L of the
Building Regulations, subsequently achieving a higher SAP
or NHER rating.
The Greenstar CDi condensing regular & system boiler series
76
Versatility
Gas
The Greenstar CDi regular and system series are available for
use with both natural gas and LPG.
Controls
The Greenstar CDi Conventional series features:
•
Power on/off switch.
•
Variable temperature control selector.
•
An integral fascia with status display lights and a digital
display which also operates as a fault diagnosis display.
•
DHW control for use with Intelligent System Package*.
The CDi regular and system series design benefits
in operation
Whenever a demand for DHW or CH is made, the boiler’s
electronic control system is energised and the burner
electronically ignites via a flame ionisation system.
The pre-mix burner automatically adjusts to the set level.
The flow temperature of the boiler is then maintained at the
customer setting by the fascia mounted variable control.
Should the system requirements reduce during operation
(TRVs closing down, etc.) and the flow temperature exceed
the customer setting then the burner will modulate
downwards to match the system demand level. Should the
flow temperature continue to rise then the burner will be
de-energised and the control system will go into an
anti-cycle mode and not allow the appliance to re-fire for a
set period.
Options
Fluing
The Greenstar CDi series features 2 different sizes of
multi-directional RSF flue systems, 100mm or 125mm.
The flue can be run horizontally or vertically with additional
90 or 45 degree in-line bends allowing changes of route or
direction, providing an extremely flexible and versatile fluing
system enabling the appliance to be sited virtually
anywhere.
More details are shown on page 18.
*30CDi System boiler only
System boiler
layout
(System boiler
with low
pressure hot
water cylinder)
Cold water
storage cistern
Hot water cylinder
Worcester
system boiler
with programmer
Room
thermostat
Motorised
valve
Hot water to baths,
showers and basins etc
Pump
System
boiler layout
(System boiler
with unvented
hot water
cylinder)
Hot water cylinder
Worcester
system boiler
with programmer
Cold mains
Room
thermostat
Pump
Motorised
valve
Hot water to baths,
showers and basins etc
Regular
boiler layout
Cold water
storage cistern
Feed and
expansion
cistern
Hot water cylinder
Programmer
Worcester
regular boiler
Room
thermostat
Motorised
valve
Pump
Hot water to baths,
showers and basins etc
Greenstar CDi
System model
BBT1253 G_CDi Rg+Sys TS c08_07 25/6/07 09:21 Page 6