Worcester 24I RSF COMBI, 28I RSF COMBI User Manual

24i, 28i RSF COMBI

USER INSTRUCTIONS &

CUSTOMER CARE GUIDE

G.C. NUMBERS

NATURAL GAS L.P.G.
24i 47 311 37 47 311 38
28i 47 311 54

EXCELLENCE COMES
AS STANDARD

Thank you for purchasing a Worcester gas-fired

combination appliance.

Worcester appliances are made by Worcester Heat Systems
and the strictest quality control standards are demanded
throughout every stage of production.

Indeed, Worcester Heat Systems have led the field in

innovative appliance
design and performance
for more than 30 years.

The result is that your
new Worcester 24i or 28i
appliance offers you the
very best of everything –
quality, efficiency,
economical running costs,
proven reliability and
value for money.

What’s more, you also
have the assurance of our
no-nonsense 1 year parts
and labour guarantee.

And it’s backed up by Worcester Care Call – a complete
maintenance scheme to keep your boiler operating at peak
condition and efficiency.

No wonder that more and more people are agreeing that
when it is gas, it has to be a Worcester 24i or 28i

Page No.

Operating Instructions

.................................... 3-11

Fault and Breakdowns 12

Maintenance and
Extended Warranty

Information ............ 13-14

Guarantee Details ... 15-16

CONTENTS

2

GENERAL INFORMATION

GAS SAFETY (INSTALLATION AND USE)
REGULATIONS 1998

It is the law that all gas appliances must be installed by a
competent person in accordance with the above regulations. Failure to
install appliances correctly could lead to prosecution. It is in your
interest and that of safety to ensure compliance with the law. The
manufacturers notes must not be taken, in any way, as over-riding
statutory obligations.

WARNING: This appliance must be earthed and protected by a 3
amp fuse.

ELECTRICITY SUPPLY: 230V ~ 50Hz

IMPORTANT: To get the best from your Worcester appliance

please read these instructions carefully.

NOTE: In the event of a fault the appliance should not be used
until the fault has been corrected by a competent person.

BENCHMARK

All CORGI Registered Installers carry a CORGI ID card and have
a registration number which must be recorded in your central heating
log book. You can check that your installer is CORGI registered by
calling CORGI on 01256 372300.

GENERAL DESCRIPTION

(See Fig.1.)

The WORCESTER 24i or 28i is a combined domestic hot water
and central heating appliance. It consists of a gas fired boiler having a
varying output of between 7.5 kW and 23.4 kW (24i) or 8.5 kw and

27.5 kw (28i), a combined heat-exchanger and all necessary controls to
provide mains fed domestic hot water and central heating.

The appliance can operate in one of two modes as required. Hot
water only or hot water and central heating.

Hot Water Mode:

When a demand is made for hot water by opening a tap or
shower the flow switch will energise and the burner will light at its
maximum setting.

When hot water is no longer required the appliance pump and
fan may continue to operate to dissipate the excess heat within the
boiler.

3

4

A flow restrictor is fitted within the appliance which limits the
hot water delivery rate to a maximum of 8.0 (±15%) litres/minute
(1.8 gallons/minute) 24i or 10 (±15%) litres/minute (2.2 gallons/minute)
28i.

Hot Water and Central Heating mode:

When a demand is made for heating by the system controls (i.e. a
programmer or room thermostat).

The pump will energise circulating primary water around the
heating system and the burner will light. The heat output from the
appliance in this mode has been factory set to maximum. The
appliance will operate as necessary to maintain the temperature of the
radiators at the level set by the adjustment of the Heating

Temperature Control Knob.
(See Fig. 2.)

If the system no longer
requires output to maintain
the desired room temperature,
the burner will extinguish.
The pump and fan will
continue to run for a short
period to dissipate the
residual heat from the
appliance and then switch off.

The appliance will supply
heat to the central heating
system as required. A demand
for hot water at a tap or
shower will override the
central heating function for
the period of the domestic hot
water demand.

Fig. 1. System Diagram.

Automatic

air vent

Gas to water
heat
exchanger

Circulating

pump

Fixed
by-pass

Flow
switch

CH

return

Domestic
hot water

out

Domestic

cold

supply

Safety

discharge

Pressure
relief valve

Boiler

Expansion
vessel

CH

flow

5

CENTRAL HEATING SYSTEM

During the first few hours of operation of the central heating
system, check that all radiators are being heated at an even rate.
Should the upper area of a radiator be at a lower temperature than the
base of the radiator, it should be vented by releasing air through the
venting screw at the top of each radiator. Make sure your installer
shows you how to carry out the operation. Repeated venting will
reduce the quantity of water in the system and this must be
replenished for safe and satisfactory operation of the appliance.
Should water leaks be found in the system or excessive venting be
required from any radiator, a service engineer should be contacted and
the system corrected.

SEALED HEATING SYSTEM

The appliance will be fitted to a sealed heating system which is
pre-pressurised. Your installer will advise you on the minimum and
maximum pressure that should be indicated on the pressure gauge.
See Fig. 2. Check regularly that this pressure is maintained and
contact your installer or maintenance engineer if there is a permanent
significant drop in pressure indicated on the gauge. If the system loses
pressure it should be re-pressurised as instructed by the installer
(N.B. Maximum pressure 2.5 bar).

CLEARANCES

Your installer will have provided adequate space around the
appliance for safety and servicing. Do not restrict this space by the
addition of cupboards, shelves etc. close to the appliance.

Minimum clearances in millimetres.

ROOM THERMOSTAT

A room thermostat may be fitted for control of the central heating
temperature. It will be located in one room of the home. The method
of setting a room thermostat varies with the type and manufacture.
Refer to the instructions supplied with the room thermostat.

THERMOSTATIC RADIATOR VALVES

If thermostatic radiator valves are to be fitted to the system then
they must conform to the requirements of BS2767:1972. It is advisable
to leave one valve permanently set at maximum to prevent the boiler
short cycling.

GENERAL NOTES

RSF

Left-hand side 10
Right-hand side 10
In Front 600
Above 180
Below 200