Glowworm 115-150-175-200-250-300 User manual

0020004886A 18.01.05
12563
Unvented hot water
storage cylinders
115-150-175-200-250-300
Glow-worm, Nottingham Road, Belper, Derbyshire. DE56 1JT
www.glow-worm.co.uk
To be left with the user
Instructions for Use
Installation and Servicing

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2
0020004886A
For customer service call:
01773 828100
Technical helpline: 01773 828300
For General and Sales enquiries:
Tel. [phone]
Fax: [phone]
To register your Glow-worm appliance call:
0800 073 2142
Guarantee Registration
Thank you for installing a new Glow-worm cylinder in your home.
Glow-worm appliances' are manufactured to the very highest standard so we
are pleased to offer our customers' a Comprehensive Guarantee.
We recommend you complete and return your Guarantee Registration Card as
soon as possible.
If this card is missing you can obtain a copy or record your registration by
telephoning Glow-worm's own service organisation on 01773 828100.
Our Guarantee gives you peace of mind plus valuable protection against
breakdown.

30020004886A
Contents - Testing and Certification
The instructions consist of three parts, User, Installation and Servicing Instructions.The
instructions are an integral part of the appliance and must, to comply with the current issue of
the Gas Safety (Installation and Use) Regulations, be handed to the user on completion of
the installation.
Testing and Certification
This product has been assessed and found to comply
with the requirements of the Building Regulations for
unvented hot water storage systems and must not be
altered or modified in any way.
Any alteration not approved by Glow-worm, could
invalidate the certification, warranty and may also infringe
the current issue of the Statutory Requirements.
WARNING: We cannot accept responsibility for any
damage which may occur as a result of non-observance
of these instructions.
Subject to alteration.
Spare Parts REMEMBER: Use only genuine spare
parts supplied by Glow-worm.
CONTENTS
1 Description 4
1.1 DHW Temperature Control 4
1.2 CH Control 4
1.3 Immersion Heater 4
1.4 Applications 4
1.5 Typical applications 4
1a Technical Data 4
2 Instructions for use 6
2.1 Introduction 6
2.2 Liability 6
2.3 How to use your Glow-worm hot water cylinder 6
2.4 Immersion heater 6
2.5 Important notes 6
2.6 Guarantee 7
3Note To Installer 8
3.1 Secondary System 8
3.2 Secondary Return 8
4Installation 8
4.1 Installation requirements 8
4.1.1 Siting 8
4.1.2 Mains Water Pressure 8
4.1.3 Pipework – Primary Circuit 9
4.1.4 Discharge Pipework 9
4.1.4.1 High Level Termination 10
4.2 Dimensions 10
4.3 Functional diagrams 11
4.4 Installation procedure 12
4.4.1 Primary pipework 12
4.4.2 Secondary system Pipework 12
4.4.3 Safety valve discharge pipework 12
4.4.4 Drain Valve 13
4.4.5 Electrical connections and controls 13
4.4.5.1 Immersion Heater 13
4.4.5.2 Electrical Connections and Controls 13
4.4.5.3 Control options – system wiring scheme 14
5Commissioning 16
5.1 Filling Secondary DHW Circuit 16
5.2 Filling the Primary Circuit 16
5.3 Operating the Boiler 16
5.4 Benchmark Log Book 16
5.5 User’s Instructions 16
6Maintenance 16
7Fault finding 17

4
0020004886A
1 Description
NOTE: Only the correct immersion heater containing a safety
overheat thermostat may be used for replacement.
1.4 Applications
The Glow-worm cylinder can be connected to any UK standard
boiler.
1.5 Typical applications
Single bathroom property:
Glow-worm cylinder 115
Single bathroom property with an en-suite shower room:
Glow-worm cylinder 115 / 150
Two bathroom property:
Glow-worm cylinder 150 / 175
Two bathroom property with an en-suite shower room:
Glow-worm cylinder 175 / 200
Larger properties:
Glow-worm cylinder 250 / 300
Commercial use: size depending upon hot water requirements
NOTE 1: Select the appropriate boiler to match the heating load
(with the normal allowance for heating up from cold) plus an
allowance for heating the hot water cylinder. Typically it is
practice to allow an additional 2-3 kW for the hot water production.
NOTE 2: Consideration should be given to the use of a larger
size of cylinder than shown above where high water demands
are likely.
The Glow-worm range of unvented hot water storage cylinders
are indirectly heated cylinders which are designed for use with
UK standard boilers in hot water supply systems.
Glow-worm cylinders are available in six sizes; 115, 150, 175,
200, 250 and 300 litre. The cylinders are of stainless steel
construction, insulated with EPS and enclosed in a decorative
casing. They are supplied with all necessary cold and hot water
controls and a 2 port valve for control of domestic hot water.
The Glow-worm cylinders operate using a mains water pressure
supply and do not require a feed from a cold water storage tank.
The Glow-worm cylinders have 22 mm DHW outlet and cold
water mains inlet connections for optimum flow rate. To achieve
optimum performance from the Glow-worm cylinder an adequate
cold water mains supply pressure and flow rate must be
available (see section 4.1.2: Mains Water pressure).
1.1 DHW Temperature Control
The Glow-worm cylinder is supplied fitted with a user adjustable
domestic hot water (DHW) thermostat which controls a 2 port
motorised valve and hence the temprature of the water in the
Glow-worm cylinder.
1.2 CH Control
Central heating is controlled by a separatly fitted 2 port valve
in conjunction with suitable external controls, such as a
programmer, room thermostat or thermostatic radiator valves.
The external electrical controls should be wired to the 2 port
valve and cylinder thermostat in the normal way, as shown in
the section Electrical Connections and Controls.
1.3 Immersion Heater
Glow-worm cylinders are also provided with an auxiliary back
up 3 kW electric immersion heater, including operating thermostat
and energy cut out.
The immersion heater is fitted behind the front panel. It is
designed for use in unvented installations and contains a safety
overheat thermostat in addition to the operating thermostat.
1a Technical Data
12738

50020004886A
NOTE: Heat up time based on a primary flow rate of 15 l/min at 82°C.
Temperature rise is from 15°C to 65°C for 70% of the cylinder volume.
1a Technical Data
GW 115 GW 150 GW 175 GW 200 GW 250 GW 300 Unit
Size 115 150 175 200 250 300 litres
Nominal DHW flow from
GW 115/150/175/200 15 l/min @ 60°C
GW 250/300 20 l/min @ 60°C
Maximum water supply pressure 10 bar
Maximum primary circuit pressure 2.5 bar
Expansion vessel charge pressure 4 bar
Operating pressure 3.5 bar
Pressure reducing valve 3.5 bar
Expansion relief valve 6.0 bar
T/P valve 95 / 7.0 °C/bar
Net weight 28 30 33 39 44 49 kg
Weight (full) 145 175 205 245 310 340 kg
Height 969 1179 1339 1499 1789 2109 mm
Cylinder connections:
Cold mains inlet 22 mm compression
DHW outlet 22 mm compression
Balanced pressure cold water outlet 22 mm compression
Secondary return G 3/4
Primary flow 22 mm compression
(on 2 port valve)
Primary return 22 mm compression
Electrical connections:
3 kW Immersion heater 230/240 V, 50 Hz
Three port valve 230/240 V, 50 Hz
Cylinder thermostat 230/240 V, 50 Hz
Coil Specifications:
Heat loss 1.7 1.9 2.0 2.1 2.3 2.5 kW/24h

6
0020004886A
NOTE: Access should always be maintained to allow operation
of the domestic hot water thermostat control.
2.3 How to use your Glow-worm hot water
cylinder
Your boiler and Glow-worm unvented hot water cylinder will
provide both central heating and mains pressure hot water.
Check that the boiler is operational as detailed in the instructions
for use supplied with the boiler.
The domestic hot water thermostat on the Glow-worm cylinder
can be set from 20°C to 65°C. The desired temprature will be set
by the installer while commissioning the Glow-worm cylinder
(normally a setting of 60°C is adequate).
NOTE: In hard water areas the DHW temperature selected
should not exceed this setting to avoid possible scale build-up.
If a programmer has been fitted to control the central heating
and hot water, check that this is set to the desired on and off
periods.
The boiler will then operate automatically to heat the cylinder
contents at the desired times to the temperature selected.
When domestic hot water is used, the boiler will operate to re-
heat the cylinder as required.
2.4 Immersion heater
The electric immersion heater behind the front panel is provided
as a back up means of water heating and is not intended for use
at the same time that the boiler is heating the cylinder.
2.5 Important Notes
Shutting down the Glow-worm cylinder
To shut down the heating and hot water system for short
periods, simply turn off the boiler as shown in the instructions
supplied with the boiler.
Frost protection
Please ensure that if you are absent during a period of frost the
central heating system remains in operation and the rooms and
Glow-worm cylinder are kept above freezing point. It must be
remembered however that the boiler will be automatically
switched off by built-in monitoring devices if certain faults occur,
e. g. interruption in the gas or electricity supply.
Alternatively you can drain the central heating system, boiler
and Glow-worm cylinder. Please contact your Installer.
Care and Maintenance
The casing of the Glow-worm cylinder may be cleaned with a
damp cloth and a little soap. Do not use any abrasive or solvent
material which could damage the case or fittings.
It is important that your hot water cylinder is serviced annually
by a competent person. Please contact your installer or
Glow-worm 01773 828100 for further details.
2.1 Introduction
Your Glow-worm unvented hot water cylinder and boiler, together
provide you with a modern, efficient, high performance heating
and hot water system.
Because your Glow-worm hot water cylinder is supplied with
water directly from the mains, you get the benefit of mains
pressure hot water at your hot taps, without the need for storage
tanks in the loft and without a hot water pump. The Glow-worm
cylinder is made from high quality stainless steel within an easy
clean casing. The cylinder is fully insulated using environmental
friendly EPS insulation to help keep your hot water running costs
at a minimum, and protect the environment!
Your Glow-worm cylinder is tailor made to accompany a Glow-
worm boiler as well as any other UK standard boiler. All Glow-
worm boilers are equipped with 'built-in' energy saving
technology, such as burner modulation, anti cycling control and
high efficiency heat exchangers.
Please read these instructions carefully to ensure that you get
the very best out of your heating and hot water system.
2.2 Liability
WARNING: We can accept no liability whatsoever for damage
or injury resulting from failure to observe these instructions.
Specified use
Glow-worm Glow-worm unvented cylinders are made to fulfil
the latest technical specification and official safety regulations.
These cylinders are designed for use with UK standard boilers
for use in hot water supply systems.
Use of this type is entirely at the owner's risk.
The term 'specified use' also covers observance of the operating
and installation instructions, along with adherence to the servicing
schedules. The Benchmark logbook, one for both boiler and
cylinder, should be completed by the installer and/or
commissioning engineer and handed to the user. All CORGI
registered installers carry a CORGI ID card and have a registration
number. Both should be recorded in your Benchmark logbook.
You can check your installer by calling CORGI direct on 01256
372300.
NOTE: Your Glow-worm unvented hot water cylinder must be
installed by a competent person in accordance with current
Building Regulations. Do not remove or adjust any component
part of this cylinder. In the unlikely event that your Glow-worm
develops a fault, such as a flow of hot water from the discharge
pipe, switch the boiler and immersion heater off and contact
Glow-worm or your installer.
NOTE: If the Glow-worm cylinder is installed in a cupboard used
for airing purposes please ensure that clothing or other articles
are not placed on the cylinder or its associated controls.
2 Instructions for Use

70020004886A
2 Instructions for Use
Figure 1
12528
2.6 Guarantee
Glow-worm offers a guarantee of 25 years for the stainless steel
vessel against faulty materials or maufacture provided that:
The following information is important as without it your
guarantee may be invalid.
1. The warranty will become invalid if the damage is
due to scaling, frost damage, transient voltages,
lightning strikes or any act of vandalism or mis use
2. The proof of purchase must be produced in the event
of any warranty claim (bill of sale)
3. The Glow-worm cylinder must be installed by a competent
person to the prevailing standards, installation book
and building regulations at the time of installation
4. The benchmark log book must be completed on
installation and kept up to date
5. The Glow-worm cylinder must be serviced annually
6. The installation must be in an appropriate location
and its use is restricted to potable water (chloride
levels less than 200 mg/l)
7. Tampering or modification will invalidate the
warranty
8. The guarantee card must de completed and returned
to Glow-worm. within 30 days of purchase
PLEASE NOTE THIS EXTENDED GUARANTEE IS NOT
TRANSFERRABLE AND RESTS WITH THE ORIGINAL
HOUSEHOLDER.
For all other Glow-worm parts (electrical, thermal controls,
valves and design elements Glow-worm carry a 2 year guarantee.

8
0020004886A
4.1 Installation requirements
4.1.1 Siting
IMPORTANT. With regards to the Manual Handling Operations,
1992 Regulations, the following lift operation exceeds the
recommended weight for a one man lift.
Locate the Glow-worm cylinder in the building in the most
convenient position ensuring that:
1. The discharge pipe from the tundish can be installed with a
minimum fall of 1:200 and must be terminated in a safe and
visible position (see section 4.1.4 Discharge pipework).
2. The base chosen for the unit is level and capable of supporting
the weight of the cylinder when full (see section 8: Technical
Data).
3. The installation site is frost-free. If necessary provide a frost
protection thermostat.
4. Access is available for user operation of the DHW temperature
control under the front panel.
5. Suitable clearances exist to allow installation, checking and
repressurising of the expansion vessel.
6. The installation site chosen does not result in excessive
”dead leg” distances, particularly to the point of most frequent
use.
7. A suitable cold mains water supply pipe can be provided to
the Glow-worm cylinder direct from the main water stop valve
of the building.
This product has been assessed and found to comply with the
requirements of the Building Regulations for unvented hot
water storage systems and must not be altered or modified in
any way.
The installation must be carried out by a competent person and
be in accordance with the relevant requirements of the Local
Authority, Building Regulations, Building Regulations (Scotland),
Building Regulations (Northern Ireland), and the bye-laws of
the local Water Undertaking. The installation is subject to
Building Regulation approval, notify the Local Authority of
intention to install. In the event of parts replacement, use only
genuine spare parts supplied by Glow-worm.
3.1 Secondary System
The Glow-worm cylinder is provided with all necessary safety
and control devices for unvented DHW operation.
These are as follows:
A A prefitted temperature and pressure relief valve
(95°C, 7 bar).
B A Thermal cut set at 90°C which when wired to the
2 port valve will isolate the heat source in the event
of failure of the cylinder thermostat.
C A cylinder thermostat (20°C - 60°C)
D Expansion relief valve (6.0 bar) incorporating a non
return valve.
E Pressure limiting valve (3.5 bar) incorporating a line
strainer.
Check that the cylinder has been supplied with the
following:
Packed inside cylinder carton
• Water control pack (pressure reducing valve,
expansion relief valve; connections for: balanced cold
water, secondary return, expansion vessel)
• Motorised 2 port valve
• Tundish
• Cylinder drain valve,
• Installation and user instructions.
Expansion vessel:
• 12 litre for Glow-worm cylinder 115/150
• 18 litre for Glow-worm cylinder 175/200
• 25 litre for Glow-worm cylinder 250/300
Accessories: Mounting bracket No. 370 214
Prior to installation, ensure that the Glow-worm cylinder is
stored upright in dry conditions. The Glow-worm cylinder must
be kept
upright during transportation.
Please also refer to “General Requirements“ in the
installation instructions supplied with the boiler.
3.2 Secondary Return
A scondary return connection is provided in the water
control pack.
Connect onto the 1/2“ pipe on the control group using a
WRAS approved circulation pump which incorporates a
check valve to prevent backflow (see fig. 6).
3 Note to Installer
4 Installation
4.1.2 Mains Water Pressure
The DHW performance of an Glow-worm unvented cylinder
installation will correspond to the available mains water supply
pressure and flow rate. To achieve optimum performance from
the Glow-worm cylinder a suitable cold mains water supply
must be available, i. e. the measured static pressure from the
incoming mains water supply should be at least 2.0 bar. A
corresponding flow rate at least 20-25 l/min should be available.
NOTE: Mains water pressures will reduce during periods of
peak demand. Ensure that measurements are taken during
these periods.
Example:
If the measured cold mains supply pressure is 2 bar static and
the cold mains flow rate available is 30 l/min, the available flow
rate of mixed water at 40°C will be 25 l/min (from 15 l/min hot
water from the Glow-worm cylinder @ 60 °C together with 10 l/
min cold water @ 10°C).
The Glow-worm cylinder will operate satisfactorily with water
supply pressures below 2 bar although flow rates will be
reduced. If the supply pressure is below 1 bar the Glow-worm
cylinder should not be installed. Contact Glow-worm for details
on alternative hot water supply systems.
In order to minimise frictional losses minimum 22 mm bore is
recommended for new cold mains supply pipework into the
dwelling although satisfactory performance can be achieved
with 15 mm bore pipework.

90020004886A
4 Installation
22 mm up to 9 m 0.8 m
28 mm up to 18 mm 1.0 m
35 mm up to 27 mm 1.4 m
Minimum size
of discharge
pipework from
Tundish
Maximum total
resistance allowed
expressed as a length
of straight pipe
(i.e. no elbows or bends)
Resistance
created by each
elbow or bend
4.1.3 Pipework – Primary Circuit
The primary circuit pipework between the boiler and the Glow-
worm cylinder should be installed using copper tube of minimum
size 22 mm.
If the distance between the boiler and the Glow-worm cylinder
is excessive, a larger pipe diameter may be necessary. It will be
necessary to install a circulating pump in this pipework if your
Glow-worm wall mounted boiler does not contain a built-in
circulating pump.
If the Glow-worm cylinder will be used with any other UK
Standard boiler a suitable pump must be fitted into the primary
circuit.
4.1.4 Discharge Pipework
The outlet connections of both the temperature and pressure
relief valve and expansion relief valve should be connected in
15 mm copper tube to the tundish supplied.
The tundish should be installed vertically, as close to the Glow-
worm cylinder as possible and within 500 mm of the temperature
and pressure relief outlet. It must be positioned away from any
electrical components and installed in the same space as the
Glow-worm cylinder, so that it is visible to the user.
The D1 discharge pipe from the T&S Valve/Expansion Valve
can be teed together upstream of the tundish, see fig 6. The
discharge pipework must be installed using minimum 22 mm
copper pipework from the 1 inch BSP female connection on the
tundish to a safe and visible discharge point. There must be a
vertical section of pipe at least 300 mm long, below the tundish
before any bends or elbows in the pipework. Increase the
diameter of the pipework if the total resistance of the discharge
pipework exceeds the figures shown in the table below.
The installation of the discharge pipework must be in accordance
with G3, see fig 2.
Fig. 2 Typical discharge pipe arrangement
Fig. 3 High level termination
12530 12529
28 mm discharge pipe with 4 elbows and 7 m length from
tundish to discharge point.
Resistance for 4 elbows
at 1.0 m each = 4.0 m
Resistance of discharge pipe = 7.0 m
Total Resistance = 11.0 m
The total resistance of the dischargepipework is less than
the maximumallowed for 28 mm pipework (18 m) therefore
the discharge pipework size is acceptable.
Under fault conditions, the discharge warning pipe can emit
water at near boiling temperature. Ensure the discharge pipe
terminates at a safe position where there is no risk of contact
with hot water by persons in or about the building (safe and
visible).
A suitable position for the discharge point is ideally below a fixed
Example
22 mm discharge pipe having 4 elbows and a length of 7 m from
the tundish to the discharge point:
Resistance for 4 elbows
at 0.8 m each = 3.2 m
Resistance of discharge pipe = 7.0 m
Total Resistance = 10.2 m
The total resistance of the discharge pipework is greater
than the maximum allowed for 22 mm pipework (9 m).
Therefore calculate the next largest size.

10
0020004886A
4 Installation
grating and above the water seal in a trapped gully. Downward
discharges at low level, i. e. up to 100 mm above external
surfaces such as car parks, hard standings, grassed areas, etc.
are acceptable providing that where children may play or
otherwise come into contact with discharges a wire cage or
similar guard is positioned to prevent contact, whilst maintaining
visibility.
Do not fit any valves or taps to the discharge pipework. Ensure
the pipework has at least 1:200 fall continuously from the
tundish to the discharge point.
The discharge pipe from the pressure relief valve of the boiler
may be teed-into the discharge pipework from the Glow-worm
downstream of the tundish in the horizontal pipework.
4.1.4.1 High Level Termination
Providing that the point of termination is such that persons in or
around the building will not be endangered should discharge
take place, the method of termination shown in fig. 8a is
satisfactory. Examples of points to consider when deciding
whether a location for the high level discharge is suitable are:
1. The possibility, taking into account wind effect, that someone
may be in the path of the water being discharged and if so,
whether the temperature of the discharge water will have been
sufficiently reduced to not be dangerous. Thermal conductivity
of the structure’s surface, climatic conditions and location and
orientation of the discharge pipe may or may not have an effect
on reducing the temperature of the discharge water.
2. The location of windows and similar openings.
3. The likelihood of a pram being left beneath the point of
discharge.
4. The ability of the structures surface to withstand near boiling
water.
5. The possibility of ice formation if water is discharged onto
pedestrian walkways.
Fig. 4
abcdef g
GW 115 938 969 421 351 281 556 728
GW 150 1148 1179 454 384 314 589 903
GW 175 1308 1339 454 384 314 589 1038
GW 200 1468 1499 454 384 314 589 1118
GW 250 1758 1789 454 384 314 589 1408
GW 300 2078 2109 454 384 314 589 1648
4.2 DIMENSIONS
12552

11 0020004886A
4 Installation
Fig. 5
4.3 FUNCTIONAL DIAGRAM
12553
Fig. 6
4.3 FUNCTIONAL DIAGRAM
12554

12
0020004886A
4.4 Installation procedure
IMPORTANT. With regards to the Manual Handling Operations,
1992 Regulations, the following lift operation exceeds the
recommended weight for a one man lift.
Unpack the Glow-worm cylinder and check the contents (detailed
in section 3: notes to installers).
Position the Glow-worm cylinder in accordance with section
4.1.1: Siting
4.4.1 Primary pipework
To prevent the Glow-worm cylinder from overheating the 2 port
motorised valve supplied with the boiler must be fitted to the
primary flow to the indirect coil (see figure 5).
4.4.2 Secondary system Pipework
Connect the two cold water control valves together as shown in
fig. 8, ensuring that the orientation of the valves, when installed
in the cold mains supply, allows the 15 mm outlet of the
expansion relief valve to be connected to the tundish.
Provide a cold water mains supply to the Glow-worm cylinder.
To ensure optimum performance from the Glow-worm cylinder,
and particularly in installations where the balanced pressure
cold water outlet (2, fig. 8) is to be used, the pipework provided
from the building mains stop valve to the Glow-worm cylinder
should be minimum 22 mm copper tube.
Install the drain valve in the cold mains supply between the
Glow-worm cylinder and the cold water control valves at the
lowest point.
Install the assembled cold water control valves (fig. 8) in the cold
mains supply at a convenient position adjacent to the Glow-
worm cylinder, ensuring adequate space exists for service
access and allow for connection of the discharge pipe from
expansion relief valve.
The Glow-worm cylinder is provided with an external expansion
vessel.
Connect the expansion vessel to the installed water controls by
either:
i. Screwing the vessel directly into the control assembly at the
purpose provided connection (1, fig. 8) or,
ii. Connecting the vessel to the control assembly via
copper pipe or a suitable approved flexible connec-
tion hose, ensuring that the vessel is adequately
supported.
NOTE: An optional ”Remote Expansion Vessel Mounting Kit” is
available for use with Glow-worm cylinders. The kit contains a
wall mounting bracket.
Connect the balanced pressure cold water supply (if required)
to the cold water control pack (see fig. 8).
NOTE: In areas where the mains water pressure is high (4 bar
or above) the cold water supply to a bath or shower mixer valve
can be taken from the balanced pressure cold water outlet (2,
fig. 8) of the cold water controls. This will ensure that both hot
and cold supplies to the mixer valve are at approximately the
same pressure. The cold water supply for all other terminal
fittings should be teed into the cold water supply pipework to the
Glow-worm upstream of the cold water controls.
Connect the DHW outlet pipework to the 22 mm domestic hot
water outlet on the Glow-worm cylinder. Continue with 22 mm
size pipe to the first tee fitting after which 15 mm pipework
should be adequate. If the pipe runs are of excessive length or
there are several terminal fittings supplied, extend the length of
pipework in 22 mm.
Connect the secondary return if required as shown in 3.2:
Secondary Return.
4 Installation
Fig. 7
Fig. 8
IMPORTANT: No isolation valve shall be installed between
the assembled cold water control valves and the cylinder.
12555
12556
4.4.3 Safety valve discharge pipework
Connect the temperature/pressure relief and expansion relief
valves to the tundish using 15mm pipe and install the discharge
pipework from the tundish in accordance with section 4.1.4:
Discharge Pipework.
4.4.4 Drain Valve
The drain valve (offered as accessory) has to be fitted in the cold

13 0020004886A
1
22
3
water mains supply between the Glow-worm cylinder and the
cold water control valves as low as possible (see fig. 6)
We recommend to fit a hose pipe in the outlet of the drain valve
approximately 1 meter below the bottom of the cylinder (this can
be achieved by connecting a suction hose to the outlet of the
drain valve).
4.4.5 Electrical connections and controls
All electrical connections conform to BS.
The position of the discharge pipes (tundish), drain
valves and motorised valves etc. shall be positioned
away from any electrical components.
4.4.5.1 Immersion Heater
The Glow-worm 115 - 300 cylinders are equipped with a factory
fitted immersion heater.
All internal wiring is factory mounted.
WARNING: The immersion heater must be earthed.
Install a separate electrical supply to the immersion heater in
accordance with the current IEE wiring regulations (BS 7671).
The immersion heater must be wired in 2.5 mm2 heat-resisting
cable from a double pole isolating switch. The circuit must be
protected by a 13 amp fuse. The connection details for the
immersion heater are shown in fig. 9.
IMPORTANT: The immersion heater incorporates an energy
cut-off device and must not under any circumstances be replaced
by a standard immersion heater.
Only a correct genuine Glow-worm spare part is permitted.
4.4.5.2 Electrical Connections and Controls
WARNING: The Glow-worm cylinder must be earthed.
The Glow-worm cylinder and accompanying boiler may be
controlled using various programmers and room thermostats,
details of which are given in section: Control Options.
The Glow-worm cylinder has a prefitted cylinder thermal cut out
and thermostat, supplied with 1 m of 3 core and earth flying lead.
All internal wiring is factory mounted.
The thermostat which controls the DHW temperature (see fig.
9) is adjustable between 20 and 65 °C. The built in safety
thermal cut out operates at 90 °C. Should the thermal cut out be
brought into operation, the motorized 2 port valve will operated
and shut the primary flow to the cylinder. Press the reset button
(3, fig. 9) to reset thermal cut out and motorised valve.
IMPORTANT: Before resetting the thermal cutout or changing
the temperatur setting of the thermostat, set the electrical
supply off.
Connections to wiring centre
Provide a wiring centre adjacent to the cylinder to make the
electrical connections.
Connect the Glow-worm boiler terminals to the corresponding
terminals of the wiring centre.
Connect the Glow-worm cylinder controls flying lead and the 2
port valve flying lead to the terminals of the wiring centre.
Connect the terminals of the programmer and room thermostat
to the terminals of the wiring centre.
Connect a 3 amp fused mains supply to the terminals of the
wiring centre.
NOTE: All wiring must be carried out in accordance with BS
7671: Requirements for electrical installations (IEE Wiring
Fig. 9
IMERSION HEATER
ELECTRICAL CONNECTIONS
4 Installation
12557
Regulations, 16th edition).
Check that the sensors from the immersion heater and the
cylinder are positioned correctly in the tubes.

14
0020004886A
4.4.5.3 Control options – system wiring scheme
IMPORTANT: 1-10 must go to the corresponding number
in the wiring centre.
4 Installation
Fig. 10
2x2 PORT VALVE SYSTEM
12558
*This valve is required even if a
3 port valve is used.

15 0020004886A
Fig. 11
CONNECTION DETAILS BETWEEN
PROGRAMMER AND WIRING CENTRE
4 Installation
12559

16
0020004886A
5.1 Filling Secondary DHW Circuit
NOTE: Do not manually open the temperature and pressure
relief valve or expansion relief valve for venting purposes (any
foreign matter in the pipework may cause damage to the valve
seats).
Ensure that the cylinder drain valve (9, fig. 6) is closed.
Open all the hot and cold water taps or other terminal fittings.
Open the mains water supply to the Glow-worm cylinder and
continue filling until water runs freely from the terminal fittings,
ensuring all air pockets are purged.
Close the terminal fittings and check the system for leaks.
Specially check the connection of the immersion heater for
leaks.
The system should now be thoroughly flushed.
Open hot water taps at opposite ends of the system and allow
water to discharge for at least 5 minutes.
Close the hot water taps.
5.2 Filling the Primary Circuit.
NOTE: Do not use boiler pressure relief valve for venting
purpose.
The complete primary CH system must be flushed out with both
cold and hot water. Fill and vent the central heating system as
detailed in the boiler installation instructions.
To assist with this operation set the manual override lever on the
2 port diverter valve (fig. 7) to the MANUAL position, and lock
in this position by pushing the lever into the valve head.
Completely drain the CH system, then refill and vent.
Reset the lever on the 2 port valve to the ”AUTO” position by
releasing the manual operating lever from the valve head (pull
outwards). For commissioning purposes and to reduce the time
for the cylinder contents to reach temperature, set the cylinder
hot water thermostat knob to setting middle position (approx.
40°C).
Operate the boiler as in section 5.3 until both the cylinder has
reached temperature and all radiators in the system are hot.
Then once again drain the complete CH system to remove
residues from the pipework and refill and vent again as above.
Reset the manual operating lever on the 2 port valve to the
”AUTO” position once the system has been refilled and vented.
5 Commisioning
5.3 Operating the Boiler
Ensure the boiler mains switch is turned on.
Ensure that the programmer and thermostats are calling for
heat.
Check that the boiler fires and heats the cylinder contents and
the radiators according to the DHW and room thermostat
settings.
Carry out the commissioning and testing procedures detailed in
the installation instructions supplied with the boiler.
Upon completion of the commissioning procedures, set the
DHW thermostat knob on the Glow-worm cylinder to setting 5-
6, approx. 60°C, and set the back up immersion heater (fig. 9)
thermostat to 60°C.
5.4 Benchmark Log Book
Complete the Benchmark Log Book included in the instructions.
5.5 User’s Instructions
Hand these instructions for use to the user for retention and
instruct in the safe operation of the boiler and cylinder. Advise
the user of the operation of the cylinder thermostat and the
immersion heater thermostat, and that normally a setting of
max, which gives a stored water temperature of approximately
60°C is adequate.
NOTE: In hard water areas the DHW temperature setting
should not exceed this setting to avoid possible scale build-up.
Advise the user of the precautions necessary to prevent damage
to the system and to the building if the system does not remain
operative during frost conditions.
Advise the user that the immersion heater is provided as a back
up means of water heating and is not intended for use at the
same time that the boiler is heating the cylinder.
Finally, advise the user that for continued efficient and safe
operation, the boiler and Glow-worm cylinder should be serviced
at least once a year by a qualified servicing company. It is
important and strongly recommended that arrangements are
made for a maintenance agreement with a qualified servicing
company to ensure regular servicing of the boiler and cylinder.
Please contact Glow-worm's Own Service Organisation
(01773-828100) for further details.
NOTE: Leave installation, servicing and user instructions with
the user.
6 Maintenance
The following maintenance work has to be carried out annually
by the competent installer or Glow-worm's Own Service
Organisation.
Inspection of pressure/temperature relief valve and expansion
relief valve.
Manually operate each valve by twisting the operating cap, and
check if water flows unobstructed via the tundish to the discharge
point. Ensure that both valves re-seat satisfactorily.
Check pressure of expansion vessel.
Turn off mains water supply and open nearest hot water tap to
depressurise the secondary water system.
Check the expansion vessel charge with a pressure gauge at
the test point. If the pressure is below 3.0 bar, top up with
suitable air pressure pump.
Servicing procedures for the Glow-worm boiler are contained in
the boiler installation and servicing instructions.
Complete the service section of Benchmark Log Book.
NOTE: In the event that parts require replacement, use only
genuine spare parts supplied by Glow-worm.

17 0020004886A
12561
Fig. 13
FAULT B
7 Fault Finding
12560
Fig. 12
FAULT A

18
0020004886A
7 Fault Finding
12564
Fig. 14
FAULT C

19 0020004886A
7 Fault Finding
12562
Fig. 15
FAULT D