gledhill GB10 User guide

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_____________________________________________________________________________________
A wall mounted high efficiency condensing Gledhill Boiler
DESIGN, INSTALLATION AND SERVICE INSTRUCTIONS
_____________________________________________________________________________________
GENERAL
This high efficiency wall mounted condensing boiler is designed to
provide central heating from a fully pumped open vented or sealed
water system when coupled to a thermal store or an indirect cylinder.
The central heating water temperature can be adjusted by the installer
to suit special applications.
Once the controls are set, the boiler operates automatically and the
boiler controller automatically activates the frost protection program to
prevent the boiler from freezing.
This boiler is for use with Natural Gas (G20) only at 20mbar inlet
pressure and is for use in GB &IE only.
Appliance category: I2H Appliance types: C13, C73, C33
These instructions cover the following boiler models and only apply to
the appliances sold and installed in Great Britain (GB) and Ireland (IE).
These appliances have been certified for safety and therefore it is
important these instructions must be followed. Both the appliance and
the installation specifications must not be modified unless
recommended and approved by Gledhill Limited in writing. Any
alteration not approved by Gledhill Ltd., could invalidate the
certification, boiler warranty and may also infringe the current issue of statutory requirements.
The Gas Safety (Installation and use)
Regulations 1998
“In your own interest, and that of safety, it is law
that all gas appliances are installed by
competent persons, in accordance with the
above regulations. Failure to install appliances
correctly could lead to prosecution.”
Control of Substances Harmful to Health
When working with insulation materials, avoid inhalation as it may be harmful to health. Avoid contact with
skin, eyes, nose and throat. Use disposable protection. Dampen the material and ensure that the area is well
ventilated.
INSTRUCTIONS
The instructions are an integral part of the appliance and therefore read these Instructions before installing or
lighting the appliance. Also to comply with the current issue of the Gas Safety (Installation and Use), these
instructions and the ‘Benchmark’ Log Book must be handed to the user on completion of the installation.
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Gledhill wall mounted condensing boiler models
Model
Reference SEDBUK Rating Gas Council Number
GB10 90.1 % - Band ‘A’
GB15 90.3 % - Band ‘A’
GB20 90.4 % - Band ‘A’
GB25 90.4 % - Band ‘A’
GB30 90.3 % - Band ‘A’

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Contents
Page
1. IMPORTANT INFORMATION 3
2. OPERATING THE BOILER 7
3. INSTALLATION, DESIGN & PLANNING INFORMATION 9
4. BOILER INSTALLATION 21
5.ELECTRICALWIRING 23
6.COMMISSIONING 26
7.SERVICING 28
8. FAULT FINDING 30
9 REPLACEMENT OF PARTS 35
10. SPARE PARTS 38
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1. IMPORTANT INFORMATION
1.1. GAS TESTING AND CERTIFICATION AND CE MARK
These boilers have been tested and certified for safety and performance. It is important that no alteration is
made to the boiler unless it is approved in writing by Gledhill Ltd.
The boiler meets the requirements of Statutory Instrument No 3083 i.e. ‘The Boiler (Efficiency) Regulations’
and therefore it is deemed to meet the requirements of Directive 92/42/EEC. The product has been certified
by the Notified body Advantica 0087 and the production is certified by the notification body BSI 0086.
The CE mark on this appliance shows compliance with:
(a) Directive 90/396/EEC on the approximation of laws relating to appliances burning gaseous fuels.
(b) Directive 73/23/EEC on the harmonisation of laws of the Member States relating to electrical equipment
designed for use within certain voltage limits.
(c) Directive 89/336/EEC on the approximation of the laws of Member States relating to electromagnetic
compatibility.
1.2. SPARE PARTS
When replacing spare parts on this appliance, remember to use only spare parts that you can be assured to
conform to the safety and performance specification that we require. Do not use reconditioned or copy parts
that have not been clearly authorised by Gledhill Ltd.
1.3. HANDLING AND STORING THE APPLIANCE
This appliance should be handled carefully to avoid damage and any manual handling/lifting operations will
need to comply with the requirements of the Manual Handling Operations Regulations issued by the H.S.E.
During the appliance installation it will be necessary to employ caution and assistance whilst lifting as the
appliance or component exceeds the recommended weight for a one man lift.
Take care to avoid trip hazards, slippery or wet surfaces. In certain situations it may be necessary to use
mechanical handling aids.
If the unit needs to be stored prior to installation it should be stored upright in a dry environment and on a
level base.
1.4. SYSTEM INSTALLATION
Any installation must be in accordance with the relevant requirements of the current issue of Gas Safety
(Installation and Use) Regulations, Local Building Regulations, Local Water Company Bylaws and Health &
Safety Document No. 635 – The Electricity at Work Regulations 1989. The detailed recommendations are
contained in the current issue of the following British Standards and Codes of Practices: -
BS 5440 Pts. 1 & 2; BS 5449; BS 5546; BS 7074 Part 1; BS 6700; BS 6798; BS 6891, BS 7593,
IGE/UP/7/1998
1.5. WARNINGS
(a) Gas Leak or Fault
If a gas leak or fault exists or is suspected, turn the boiler mains electricity supply off and turn off the
gas supply at the meter. Consult your local gas company or your local installation/servicing company.
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(b) Clearances
If fixtures are positioned close to the boiler, space must be left as shown in figure 3.10.2. Enough space
must also be left in front of the boiler to allow for servicing.
(c) Sheet Metal Parts
This boiler contains metal parts (case & components) and therefore care should be taken when
handling and cleaning, with particular regard to edges.
(d) Sealed Components
This boiler uses fully premix burner with air/gas ratio controller therefore the burner input i.e. CO and
CO2settings and the burner off set pressure are factory set and sealed and require no onsite
adjustments during installation or routine servicing.
Under no circumstances the user should interfere with the sealed components as this could result in a
potentially dangerous situations arising. If sealed components in the appliance are replaced and/or re-
commissioned in the field then these must be done strictly in accordance with manufacturer’s
instructions and these components must be re-sealed.
(e) Bench Mark Log Book
As part of the industry wide ‘Benchmark’ initiative all Gledhill appliances now include a Benchmark
Installation, Commissioning and Service Record Logbook. Please read this carefully and complete all
sections relevant to this appliance. Failure to do so may affect warranty.
1.6. EQUIPMENT SELECTION
This information is provided to assist generally in the selection of equipment. Responsibility for selection and
specification of our equipment must, however, remain that of our customers and any expert or consultants
concerned with the installation(s). Therefore please note that: -
(a) We do not therefore accept any responsibility for matters of design selection or specification for the
effectiveness of an installation containing one of our products.
(b) All goods are sold subject to our Conditions of Sale, which are set out in the Appendix to this
document.
1.7. ELECTRICITY SUPPLY FAILURE
(a) This boiler must be earthed and the boiler will not work without an electricity supply.
(b) Reset any external controls to resume normal operation of the central heating.
(c) Normal operation of the boiler should resume when the electrical supply is restored. If the boiler does
not resume normal operation turn the mains switch off and on. If the boiler does not resume normal
operation after this, the overheat thermostat may have operated. The overheat thermostat would only
operate under abnormal conditions and, under these circumstances it would be advisable to consult
your installation/servicing company.
1.8. PROTECTION AGAINST FREEZING
(a) The boiler has built in frost protection programme as long as the electricity and gas are left switched on.
The boiler controller operates the burner and the system pump when the temperature inside the boiler
falls below 4oC.
(b) Any other exposed areas of the heating and hot water system should be protected by a separate frost
thermostat.
(c) If the mains electricity and gas supplies to the boiler system are to be turned off for any long periods
during severe weather, it is recommended that the whole system including the boiler should be drained
to avoid risk of freezing. In this case ensure that the immersion heater in the cylinder if fitted is switched
off.
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(d) If you have a sealed heating system, contact your installation/service company as draining, refilling and
pressurising MUST be carried out by a competent person.
(e) As a safety feature, the boiler will stop working if the condensate drain becomes blocked. During
freezing conditions this may be due to the forming of ice in the condensate drain external to the house.
Release ice blockage by use of warm cloths on the pipe. Contact your installation/service company if
the fault persists.
1.9. BOILER INSTALLATION IN A COMPARTMENT OR CUPBOARD
If the boiler is fitted into a compartment or a cupboard, it does not require ventilation openings. However, do
not use the compartment or cupboard for storage.
1.10. BOILER CASING
Do not remove or adjust the casing in any way, as the incorrect fitting may result in incorrect operation or
failure to operate at all.
1.11. CONDENSATE DRAIN
The condensate drain must not be modified or blocked (See section 3.13)
1.12. PLUMING FROM FLUE TERMINAL
This is a high efficiency-condensing boiler and hence flue gas temperature will be low. Therefore like all
condensing boilers this appliance will produce a plume of condensation in cool weather. It is normal and not
a fault condition, but this should be taken into account when positioning the boiler.
1.13. CLEANING
This boiler contains metal parts and therefore care should be taken when handling and cleaning, with
particular regard to edges.
The boiler casing can be cleaned using a mild liquid detergent with a damp cloth and then a dry cloth to
polish. Do not use any form of abrasive or solvent cleaner as you may damage the finish.
1.14. MAINTENANCE AND SERVICING
This appliance must be serviced and installed by a competent person e.g. CORGI Registered installer. All
CORGI registered installers carry a CORGI ID Card and have a registration number. You can call CORGI
direct on 01256 372300.
For the continued efficient and safe operation of the boiler, it is recommended that it is checked and serviced
at regular intervals. The frequency of service will depend upon the installation condition and usage, but in
general, once a year should be enough.
If this boiler is installed in a rented property, there is a duty of care imposed on the owner of the property by
the current issue of the Gas Safety (Installation and Use) regulations, Section 35.
The installation / service engineer should complete the ‘Benchmark’ logbook on completion of commissioning
and service work.
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1.15. REPLACEMENT PARTS
Free of charge replacement for any faulty components are available from Gledhill Ltd during the in-warranty
period (normally 12 months).
After this the spares can be obtained direct from Gledhill Ltd using the ‘Speed Spares’ service. Help and
advice is also available from our Technical Help Line on 01253 474401.
Please quote the name and model of the appliance when requesting for help or ordering spares. This
information will be on the front of the appliance next to the main switch.
1.16. CONTINUOUS IMPROVEMENTS
In the interest of continuously improving the Gledhill Boiler range, Gledhill Water Storage Ltd reserves the
right to modify the product without notice and in these circumstances this booklet, which is accurate at the
time of printing, should be disregarded.
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2. OPERATING THE BOILER
2.1. HEATING SYSTEM AND BOILER
(a) Sealed Systems
A sealed heating system must be filled and pressurised by a competent person. Only light the boiler
when you are sure that the system and the boiler have been filled and pressurised.
The pressure should read at least 0.5bar, anything less than this figure could indicate a leak and you
MUST contact your installation / servicing company.
(b) All Systems
Check that the electrical supply to the boiler is ON at the external system isolator. Set any remote
controls as required.
This is a fan flued appliance and therefore the fan operation may be heard. The boiler flow temperature
is factory set at 80±2oC and is not user adjustable. (Note: The boiler flow temperature can be adjusted
between 60 and 80oC by the installer for special applications)
2.2. USER CONTROLS
The appliance control panel is
shown in diagram 2.1. The
appliance on-off switch should
be left in the ON position
(indicated by flame symbol) for
normal operation otherwise the
built in boiler frost protection will
not function.
The two-digit display indicates
the status of the boiler and the
push buttons are used for setting and resetting the controller as shown in diagram 2.2.
S3
S2
Set/Reset
-+
S1
Mains/Reset
Switch
D1 D2
0
I
Diagram 2.1
a1
a2
S3
S2
Set/Reset
-+
S1
Mains/Reset
Switch
D1 D2
0
I
Diagram 2.1
a1
a2
(a) Central heating and hot water
 Switch the boiler on-off switch to position ‘ON’ position indicated by a ‘flame’ symbol and the dot D1 will
begin to flash to indicate that the boiler controller is active.
 Set the remote user controls e.g. programmer and room thermostat so that hot water heating and/or
central heating demands are active.
 When the boiler senses the heating demand, indicated by horizontal bar ‘a2’, the boiler switches on the
boiler pump (indicated by bar ‘a1’) and starts the boiler firing sequence.
 When the boiler has lit, the dot D1 will stop flashing and will be on constantly.
 If the boiler fails to ignite, the dot D1 will switch off and dot D2 will either be either flashing or be on
constantly (depending upon the error type) and reset will be required.
 When the demand for boiler firing stops i.e. heat is not required for space heating or hot water, the boiler
will stop firing and this will be indicated by flashing dot D1 and bar a2 will switch off. After a period of
about 3 minutes the boiler pump will switch off indicated by bar a1.
(b) To Reset Boiler
Press reset button S1. If the dot D1 starts to flash and the dot D2 switches off, the boiler has reset. If the fault
persists contact your installer/service provider.
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2.3. TO TURN THE BOILER OFF
Turn the mains /reset switch to the off position (indicated by disc). Turn the gas supply off at the gas service
cock if the boiler is to be out of use for some time.
D1
flashing D2
Controller on standby
Boiler off
D1
flashing D2
Boiler in Ignition sequence
Boiler heat demand present
Boiler pump on
D1
ON D2
Boiler has lit
Boiler heat demand present
Boiler pump on
D1
flashing D2
Boiler off
Heat demand not present
Boiler pump on
D1
on D2
Frost protection program on
Boiler pump on
D1 D2
On/flashing
Boiler lockout error
Reset required
Diagram 2.2 Boiler display indication
D1
flashing D2
Controller on standby
Boiler off
D1
flashing D2
Boiler in Ignition sequence
Boiler heat demand present
Boiler pump on
D1
ON D2
Boiler has lit
Boiler heat demand present
Boiler pump on
D1
flashing D2
Boiler off
Heat demand not present
Boiler pump on
D1
on D2
Frost protection program on
Boiler pump on
D1 D2
On/flashing
Boiler lockout error
Reset required
D1
flashing D2
D1
flashing D2
Controller on standby
Boiler off
D1
flashing D2
D1
flashing D2
Boiler in Ignition sequence
Boiler heat demand present
Boiler pump on
D1
ON D2
D1
ON D2
Boiler has lit
Boiler heat demand present
Boiler pump on
D1
flashing D2
D1
flashing D2
Boiler off
Heat demand not present
Boiler pump on
D1
on D2
D1
on D2
Frost protection program on
Boiler pump on
D1 D2
On/flashing
D1 D2
On/flashing
Boiler lockout error
Reset required
Diagram 2.2 Boiler display indication
.
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3. INSTALLATION DESIGN AND PLANNING INFORMATION
3.1. IMPORTANT NOTICE
(a) The boiler is supplied in one pack. The flue and fixing jig are supplied separately.
(b) This boiler is for use on G20 natural gas only. The boiler is certified to the current issue of EN483 for
performance and safety. It is important that no alteration is made to the boiler, without written
permission of Gledhill Ltd.
(c) Where no British Standards exist, materials and equipment should be fit for their purpose and of
suitable quality and workmanship.
(d) The installation of this boiler must be carried out by a competent person e.g. CORGI Registered
installer, must comply with the relevant requirements of : -
 Manufacturer’s instructions supplied
 The Gas Safety (Installation and use) Regulations, The Building Regulations and local Water
Company Bylaws. The Health and Safety at Work Act, Control of Substances Hazardous to Health,
The Electricity at Work Regulations and any other applicable local regulations.
 The detailed recommendations are contained in the current issue of BS 5440 Pts. 1 & 2; BS 5449;
BS 5546; BS 7074 Part 1; BS 6700; BS 6798; BS 6891, BS 7593, IGE/UP/7/1998
(e) When installing the boiler, care should be taken to avoid any possibility of personal injury when handling
sheet metal parts.
(f) Refer to Manual Handling Operations, 1992 regulations.
CONDENSATE
DRAIN
INSIDE WALL
FIXING FACE
BOILER
Centre Line
GAS
CONDENSATE
DRAIN
Dia
g
ram 3.1 Boiler Models GB30
,
GB25
,
GB20
Clearances From Fixed surfaces
Top – From ‘A’ :220mm
Bottom – From ‘B’ :200mm
Sides – From ‘C’ :20mm
Front – From ‘D’ :600mm
A
B
C
D
C
GAS
CONDENSATE
DRAIN
INSIDE WALL
FIXING FACE
F+R
FLOW
& RETURN
BOILER
Centre Line
GAS
CONDENSATE
DRAIN
Clearances From Fixed surfaces
Top – From ‘A’ :220mm
Bottom – From ‘B’
Sides – From ‘C’ :20mm
Front – From ‘D’ :600mm
A
B
C
D
C
130mm
85mm
150mm
140mm
580mm
100mm
100mm
150mm
70 mm
50mm
Cut flue terminal at
plain end to length
required allowing
40mm extra for
socket elbow joint
730mm
360mm
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Dia
g
ram 3.2 Boiler Models GB10 and GB15
CONDENSATE
DRAIN
INSIDE WALL
FIXING FACE BOILER
Centre Line
GAS
CONDENSATE
DRAIN
Clearances From Fixed surfaces
Top–From ‘A’ :220mm
Bottom–From ‘B’ :200mm
Sides–From ‘C’ :20mm
Front– From ‘D’ :600mm
Clearances From Fixed surfaces
:220mm
:20mm
:600mm
Top–From ‘A’
Bottom
Sides–
Front–
–From ‘B’
From ‘C’
From ‘D’
A
B
C
DC D
50mm
GAS
CONDENSATE
DRAIN
INSIDE WALL
FIXING FACE
F+R
70 mm
C
B
FLOW
& RETURN
BOILER
Centre Line
GAS
C
A
140mm
85mm
150mm
100mm
100mm
210mm
730mm
Cut flue terminal at
plain end to length
required allowing
40mm extra for
socket elbow joint
580mm
CONDENSATE
DRAIN
300mm
140mm
3.2. TECHNICAL DATA OF BOILERS
The main dimensions and the clearances required for the boilers are shown in diagram 3.1 for models GB30,
GB25 and GB20 and diagram 3.2 for models GB15 and GB10. The technical data of the boilers is shown in
tables 3.1 and 3.2. The boiler data badge is positioned on the inner door.
The Seasonal Efficiency Domestic Boilers UK (SEDBUK) of Gledhill Boilers (all models) is Class ‘A’. The
values used in the UK Government’s Standard Assessment Procedure (SAP) for energy rating of dwellings.
The test data from which it has been calculated has been certified by Advantica.
Table 3.1. Connection, Electrical and Weight data of the boiler
Boiler ModelGB30, GB25, GB20 GB15, GB10
Height (mm) 580 580
Width (mm) 380 380
Overall dimensions
including flue spigot Depth (mm) 360 300
Height (mm) 1000 1000
Width (mm) 420 420
Clear space required
for installation Depth (mm) 500 440
Weight (kg) 33 31
Water content (litres) 1.5 1
Minimum 1.0 / (0.1) 1.0 / (0.1)Working pressure
(m wg / (bar)) Maximum 30.0 / (3.0) 30.0 / (3.0)
Gas Rc1/2, (1/2in BSP) Rc1/2, (1/2in BSP)
Water 22mm copper 22mm copper
Connections Condensate Drain 22mm Plastic pipe 22mm Plastic pipe
Electricity supply 230V, ~50Hz, Fused at 3A 230V, ~50Hz, Fused at 3A
Electrical rating 60W @230V ac 60W @230V ac
Electrical data Internal fuse rate Main PCB 3.15AT Main PCB 3.15AT
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Table 3.2. Thermal, combustion and gas data
Boiler ModelRating GB30 GB25 GB20 GB15 GB10
Maximum 34.2 28.3 22.6 17.0 11.3
Gross heat input (kW) Minimum 10.0 8.5 6.8 5.1 4.6
Maximum 30.8 25.5 20.4 15.3 10.2
Net heat input, Q (kW) Minimum 9.0 7.7 6.1 4.6 4.1
Heat output, P
Non condensing (kW) Maximum 30.2 25.0 20.0 15.0 10
Maximum 32.0 27.2 22.0 16.4 10.9Heat output
Condensing mode (kW) Minimum 9.8 8.4 6.6 4.9 4.5
Case off 9.6 9.6 9.6 9.7 9.6Burner CO2(%) at maximum rate
+0.3, -0.5 Case on 9.8 9.8 9.8 9.9 9.8
Approximate Gas rate (m3/h)
- After 10min from cold Maximum 3.3 2.7 2.2 1.6 1.1
Off-set pressure at minimum rating (mbar) - 8.0 - 10.0 -10.0 -10.0 -9.0
Minimum water flow rate (m3/h) 1.37 1.17 0.94 0.70 0.48
3.3. GAS SUPPLY
(a) The Local Gas Supplier should be consulted at the installation planning stage in order to establish the
availability of an adequate supply of gas.
(b) An existing service pipe MUST NOT be used without prior consultations with the gas supplier.
(c) A gas meter can only be connected by the Local Gas Supplier or by his Contractor.
(d) An existing meter should be of sufficient size to carryout the maximum boiler input plus the demand of
any other installed gas appliance, (BS 6891:1988). The supply from governed meter must provide
steady inlet working pressure of 20mbar (8in wg) at the boiler. See section Technical Data for the gas
required for each specific model.
(e) The gas supply line must be purged. WARNING: before purging open all doors and windows and also
extinguish any cigarettes, pipes and any other naked lights.
(f) The complete gas installation must be tested.
3.4. ELECTRICITY SUPPLY
(a) The boiler must be permanently connected to a 230V~, 50Hz supply. This appliance MUST BE
EARTHED.
(b) All external wiring to the boiler must be in accordance with the latest I.E.E. Wiring Regulation, and any
local regulations, which may apply.
(c) There must be only one common isolator for the boiler and its control system, and it must provide
complete electrical isolation via a double pole isolator fused at 3A maximum with a contact separation of
at least 3mm in both poles.
(d) The fused spur box should be readily accessible and preferably adjacent to the appliance and it should
be identified as to its use.
(e) Alternatively the connection can be made through an unswitched shuttered socket and 3A fused 3-pin
plug both to the current issue of BS 1363 may be used, provided they are not used in a room containing
bath or shower.
(f) In the event of an electrical fault after installation of the appliance, preliminary electrical checks must be
carried out i.e. Earth Continuity, Short Circuit, Polarity, and Resistance to Earth.
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3.5. CENTRAL HEATING AND WATER SYSTEM
The Gledhill boiler is suitable for use with both vented and unvented traditional heating systems and also for
use with the thermal storage systems e.g. Gledhill BoilerMate and Gledhill SysteMate.
Plastic Pipes
When plastic pipe is to be used for the heating system, this must be suitable for the maximum pressures and
temperatures for the intended application. The class ‘S’ pipes and fittings are defined in BS 7279-1.
Some plastics are permeable to the oxygen and to prevent corrosion of system components (e.g. heat
exchanger) due to build up of oxygen, a barrier type pipe must be used i.e. pipes incorporating a polymer
barrier layer.
When plastic pipe is used, the first 2m of pipe work from the boiler (both flow and return) must be in copper.
3.5.1. Open vented heating system
(a) The open i.e. vented heating system is shown schematically in diagram 3.3. It is important that the
relative positions of the pump, cold feed and the open vent are as shown in diagram 3.3 to minimise the
chances of air ingress and pump over conditions arising.
(b) The cold feed must be 15mm minimum size. The 22mm (minimum) open vent must rise continuously
and be unrestricted.
(c) The boiler must be supplied from an unrestricted water supply taken from feed and expansion cistern
situated at a maximum height of 30 meters above the boiler.
(d) A safety valve need not be fitted to an open vented heating system.
(e) A draining tap conforming to the current issue of BS 2879, must be provided at the lowest point of the
system, which will allow the entire central heating and hot water system to be drained.
(f) The overflow/warning pipe should be in 20mm internal diameter pipe of suitable material for use in
heating systems in accordance with BS 5449 (such as copper). It should have continuous fall and
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discharge in a conspicuous external position. It should not have any other pipework directly branched
into it.
(g) The water level in the F & E cistern should be at least 250mm above the highest point on the system
including the radiators
3.5.2. Sealed heating system
(a) Design Standards
The sealed heating system is shown schematically in diagram 3.4. The sealed system installation must
comply with the appropriate requirements of current issues of BS5449, BS6759, BS6798 and BS7074.
(b) Safety Valve
A non-adjustable safety valve must be fitted to a sealed system. It shall be pre-set with a lift pressure of
3 bar and incorporate a seating of resilient material, a test device and a connection to the drain.
(c) Safety Valve Drain
The drain from a safety valve must be routed outside the building and positioned so that any discharge
can be seen. It must not discharge above an entrance or window or any type of public area and be clear
of any electrical fittings.
(d) Pressure Gauge
A pressure gauge with a set pointer and covering at least 0 – 4 bar shall be fitted permanently to the
sealed system. It should be positioned where it can be seen when filling the system.
(e) Expansion Vessel
A diaphragm type expansion vessel, conforming to the current issue of BS4814 (See also BS7074
Parts 1 and 2) must be connected to the inlet side of the circulating pump (see diagram 3.4) unless laid
down differently by the manufacturer.
The water content of the boiler is given in table 3.1.
The expansion vessel volume depends on the total water volume of the system and the initial system
design pressure as shown below in table 3.3. For any system an accurate calculation of vessel size is
given in the current issue of BS5449 and BS7074 Part 1. For example; A higher initial design charge
pressure requires a larger volume vessel.
The initial vessel charge pressure must not be less than the static head of the system, that is the height
of the highest point of the system above the expansion vessel.
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Table 3.3 Expansion vessel volume required
Safety valve setting (bar) 3.0
Vessel charge pressure (bar) 0.5 1.0 1.5
Initial system fill pressure (bar) 0.5 1.0 1.5 2.0 1.0 1.5 2.0 1.5 2.0
Total system water content (l) Expansion vessel volume (litres)
25 2.1 3.5 6.5 13.7 2.7 4.7 10.3 3.9 8.3
50 4.2 7.0 12.9 27.5 5.4 9.5 20.6 7.8 16.5
75 6.3 10.5 19.4 41.3 8.2 14.2 30.9 11.7 24.8
100 8.3 14.0 25.9 55.1 10.9 19.0 41.2 15.6 33.1
125 10.4 17.5 32.4 68.9 13.6 23.7 51.5 19.5 41.3
150 12.5 21.0 38.8 82.6 16.3 28.6 61.8 23.4 49.6
(f) Water Makeup
Provision should be made for replacing the water loss from the system using a makeup bottle mounted
in a position higher than the highest point of the system, connected through the non-return valve to the
return side of either central heating or hot water cylinder circuit.
Alternatively, provision for water makeup can be made using a filling loop, in an accessible position on
the return, or an approved CA device as discussed below.
(g) Filling a Sealed Heating System
Provision for filling a sealed system at low level must be made and the method selected must comply
with the Water regulations. The temporary filling loop method is shown in diagram 3.5 and the CA-
device method is shown in diagram 3.6.
The CA device normally requires a pressure differential to operate and this should be taken into
account when selecting the device and the system operating pressures.
There must be no permanent connection to the mains supply, even through a non-return valve.
Boiler
Flow
Return
1. Control/Isolating valve
2. Double check valve
3. Hose unions
4. Temporary connection
Diagram 3.5 Sealed system filling method 1
1
1
23
34Supply pipe
Boiler
Flow
Return 1. Control/Isolating valve
2. Type CA Backflow
Prevention device
3. Tundish
4. Air Gap
5. Pressure regulator
(optional)
Diagram 3.6 Sealed system filling method 2
1
1
4Supply
pipe
2
3
5
Boiler
Flow
Return
1. Control/Isolating valve
2. Double check valve
3. Hose unions
4. Temporary connection
Diagram 3.5 Sealed system filling method 1
1
1
23
34Supply pipe
Boiler
Flow
Return 1. Control/Isolating valve
2. Type CA Backflow
Prevention device
3. Tundish
4. Air Gap
5. Pressure regulator
(optional)
Diagram 3.6 Sealed system filling method 2
1
1
4Supply
pipe
2
3
5
3.5.3. Gledhill BoilerMate Heating System
The Gledhill Boiler is also suitable for use with a Gledhill BoilerMate; an integrated open vented heating
system and mains pressure hot water appliance. This appliance is supplied with factory fitted and wired
system controls and equipment e.g. pumps, valves etc. The BoilerMate uses a directly heated open vented
primary store and is suitable for only vented heating systems as shown schematically in diagram 3.7. For
further details refer to Gledhill BoilerMate manual.
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The BoilerMate acts as the
neutral point of the system
and therefore the cold feed
and open vent must be piped
to the appropriate connections
on the BoilerMate.
A draining tap conforming to
he overflow/warning pipe
The sealed central heating system
the current issue of BS 2879,
must be provided at the
lowest point of the system,
which will allow the entire
central heating and hot water
system to be drained.
T
should be in 20mm internal
diameter pipe of suitable
material for use in heating
systems in accordance with
BS 5449 (such as copper). It
should have continuous fall
and discharge in a conspicuous external position. It should not have any other pipework directly branched
into it.
Boiler
BoilerMate
250mm
Highest point
of the system
Warning/Overflow pipe
Open vent
Cold feed
Mains
cold supply
•No bypass is required in the boiler circuit
•Bypass valve on heating circuit not required unless the heating
circuit incorporates 2-port zone valve or TRVs on all radiators
Diagram 3.7 Schematics of a BoilerMate heating system
Remote
F &E Cistern
Return
Flow
Boiler
BoilerMate
250mm
Highest point
of the system
Warning/Overflow pipe
Open vent
Cold feed
Mains
cold supply
•No bypass is required in the boiler circuit
•Bypass valve on heating circuit not required unless the heating
circuit incorporates 2-port zone valve or TRVs on all radiators
Diagram 3.7 Schematics of a BoilerMate heating system
Remote
F &E Cistern
Return
Flow
The height of the F & E cistern above the BoilerMate should not be greater than 10m and the water level in
the F & E cistern should be at least 450mm above the highest point on the system including the radiators
3.5.4. Gledhill SysteMate Heating System
The Gledhill Boiler is also suitable for
use with a Gledhill SysteMate; an
integrated sealed heating system
and mains pressure hot water
appliance The SysteMate uses an
indirectly heated open vented hot
water only primary store. The central
heating circuit is suitable for sealed
heating systems as shown
schematically in diagram 3.8. For
further details refer to Gledhill
SysteMate manual.
When using the boiler with a
SysteMate, the pressure safety valve
must be fitted on the boiler flow pipe
adjacent to the boiler. The expansion
vessel should be fitted adjacent to
the SysteMate and connected to the
connector on the SysteMate.
design and component selection and
sizing including filling arrangements
should follow the guidelines
discussed in section 3.5.2 ‘Sealed Heating Systems’.
Boiler
SysteMate
Open vent
Cold feed
Mains
cold supply
Diagram 3.8 Schematics of a SysteMate heating system
Remote F & E
Cistern for store
Heating circuit
expansion vessel
Return
Flow
Filling point (See diagrams 3.5 & 3.6)
Pressure gauge
Safety valve
Boiler
SysteMate
Open vent
Cold feed
Mains
cold supply
Diagram 3.8 Schematics of a SysteMate heating system
Remote F & E
Cistern for store
Heating circuit
expansion vessel
Return
Flow
Filling point (See diagrams 3.5 & 3.6)
Pressure gauge
Safety valve
Although the heating system is sealed, the primary store in the SysteMate must be filled via a feed and
expansion cistern supplied with the appliance as shown in diagram 3.8. The height of the F & E cistern
above the BoilerMate should not be greater than 10m.
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3.6. SYSTEM / BOILER PUMP
The variable duty pump should be fitted
on the flow pipe from the boiler and have
isolating valves on each side as shown
schematically in diagrams 3.3 and 3.4.
The pressure loss characteristics of the
boilers are shown in diagram 3.9. The
water flow rates and the boiler pressure
losses at 11oC and 20oC temperature
differences are also tabulated below
in table 3.4.
The variable duty pump should be set to
give a temperature difference of no greater
than 20oC between boiler flow and return to give
Diagram 3.9 Pressure loss characteristics of the boilers
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500
Flowrate (litres/h)
Pressure loss (mWG)
GB_10, GB_15
GB_20, GB_25, GB_30
GB-30:
30kW =1280 l/h at 20K diff
GB-25
25kW =1070 l/h at 20k diff
GB-20
20kW = 850 l/h at20Kdiff
2.6 m
1.9 m
1.3 m
GB-15
15kW = 640 l/hat 20K diff
0.8 m
GB-10
10kW = 430 l/h at20Kdif
f
minimum flow rate through the boiler shown
in table 3.4. High resistance micro bore systems
may require a higher duty pump.
3.7. FLOW RATE
Table 3.4 Boiler pressure loss data
Boiler
Model Temperature difference (K) Flow rate (Litres) Pressure loss (m WG)
11 2342 6.66
GB30 20 1288 2.30
11 1951 4.79
GB25 20 1073 1.69
11 1561 3.22
GB20 20 858 1.17
11 1171 3.91
GB15 20 644 1.47
11 780 2.00
GB10 20 429 0.80
If it is necessary to alter the flow rate in a
system, the system can be fitted with a
lockable balancing valve in the main flow or
return pipes. The example is shown as a
valve ‘A’ in diagram 3.4.
The flow rate through the boiler must not be
allowed to fall below the values given in table
3.2 for the boiler model selected.
3.8. BYPASS VALVE
A bypass is not required on the central heating system unless the system controls could allow the boiler and
the pump to operate when there is no flow.
When a bypass valve has to be fitted, it must be placed at least 1.5 meters away from the boiler as shown
schematically in diagrams 3.3 and 3.4. An automatic bypass valve is recommended.
3.9. DOMESTIC HOT WATER STORAGE CYLINDER
Single feed indirect cylinders are not suitable.
The domestic hot water cylinder must be of the double feed fully indirect coil type. It must be suitable for
working at a gauge pressure of 0.35 bar above the safety valve setting.
When the storage vessel will not have vent to the atmosphere i.e. unvented cylinder is used, then the
installation must comply with the Building regulations and Local Water Company bylaws. See also the
current issues of BS5546 and BS6700.
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3.10. BOILER LOCATION AND VENTILATION
3.10.1. Boiler Location
The boiler may be installed in any room although particular attention is drawn to the requirements of the
current issue of BS7671 with respect to the installation of a boiler in a room containing a bath or a shower.
Any electrical switch or boiler control using mains electricity supply should be so sited that a person using the
bath or a shower cannot touch it. The electrical provisions of the Building Standards (Scotland) Regulations
are applicable to such installations in Scotland.
These boilers are not suitable for fitting outdoors. The boiler must be mounted on a flat wall, which is
sufficiently robust to take its total weight given in table 3.1.
3.10.2. Clearances
The boiler should be positioned and installed so that at least minimum clearances shown in diagram 3.10,
required for servicing and correct operation are provided. Additional clearances may be useful around the
boiler for installation and servicing.
For flue installations where external access is not practical, considerations should be given for the space
required to insert the flue internally, which may require clearances larger than those specified in diagram
3.10.
220
20 20
200
5*
Flue
Front
600
5*
5*
Diagram 3.10 Minimum clearances from
permanent fixed surfaces
All dimensions in mm
*Increase to 25mm clearances from combustible surfaces
220
20 20
200
5*
Flue
Front
600
5*
5*
Flue
Front
600
5*
5*
Diagram 3.10 Minimum clearances from
permanent fixed surfaces
All dimensions in mm
*Increase to 25mm clearances from combustible surfaces
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3.10.3. Timber Frame Buildings
If the boiler is to be installed in a timber frame building, it should be fitted in accordance with the Institute of
Gas Engineers document IGE/UP/7/1998. If in doubt, ask local gas utility company or Gledhill Ltd.
3.10.4. Room ventilation
The boiler is room sealed, so when it is installed in a room or space, a permanent air vent is not required.
3.10.5. Compartment ventilation
If the boiler is installed in a compartment, a permanent air vent Is not required. However leave existing air
vents.
3.11. FLUE LOCATION AND VENTILATION
3.11.1. Flue Position and Length
The standard horizontal flue is fitted onto the top of the boiler as shown in diagrams 3.11 and 3.12. The
dimension “X” for the rear outlet flue and dimension “Y” for the side outlet flue must be measured and
compared against the standard flue supplied to check if it is suitable.
An extended flue system can be installed with the addition of extension kits (see section 3.11.3 Flue options).
The flue system must always be designed and installed to have a continuous fall towards the boiler of at
least 3oto allow the condensate to run to drain via the boiler.
3.11.2. Internal Flue Installation
The flue can be installed from inside the building when access to the outside wall face is not practical.
3.11.3. Flue Options
The concentric flue systems and kits available for this boiler are listed below in table 3.4. Additional
accessories and flue systems are also available for this boiler. See ‘Gledhill Boiler Flue Options Guide’ for
configurations that are available.
Table 3.4 Concentric Flue Kits and Options
Description Part No.
Standard horizontal flue kit GT461
Vertical flue terminal kit – pitched AFB001
Flat roof flue kit AFB010
Ridge terminal flue kit AFB020
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The concentric flue system can be extended to a maximum equivalent length of 6.65 metres (excluding flue
terminal) after the flue elbow fitted to the appliance. This can be horizontal or vertical but the following
allowances should be made for each component fitted.
Description Equivalent Length
2m Flue extension 2.0
1m Flue extension 1.0
0.5m Flue extension 0.5
45oFlue bend 1.5
90oFlue bend 1.9
3.11.4. Terminal Position
The minimum acceptable siting dimensions for the terminal for obstructions, other terminals and ventilation
openings are shown in Gledhill Boiler Flue Options Guide. The dimensions measured are from the edge of
the terminal.
The terminal must b exposed to the external air, allowing passage of air across it at all times.
This is a condensing boiler and therefore some pluming may occur from the flue outlet. This should be taken
in to consideration when selecting the position for the terminal.
Carports or similar extensions of roof only, or roof and one wall, require special consideration with respect to
any openings, doors, vents or windows under the roof. Care is required to protect the roof if it is made of
plastic sheeting. If the carport has a roof and two or more walls, then seek advice from the local gas supply
company before installing a boiler.
3.11.5. Terminal Guard
A terminal guard is required if a person could come into contact with the terminal or the terminal could be
subject to damage. The terminal guard is required for horizontal flue terminals below 2m above the ground
floor or accessible by the general public from the windows, balconies etc.
If a terminal guard is required, it must be positioned to provide minimum of 50mm clearance from any part of
the terminal and be central over the terminal.
A terminal guard for this boiler is shown in the Gledhill Boiler Flue Options Guide and is available from
Gledhill Ltd quoting part number GF199.
3.12. HEATING SYSTEM CONTROLS
It is recommended that a programmer and a room thermostat should control the boiler when there is a
demand for central heating and a programmer and hot water store thermostat should control the boiler when
there is a demand for water heating.
The thermostatic radiator valves may be installed; however they must not be fitted in a room where the room
thermostat is located. (Note: All systems must have at least one radiator that is not fitted with a thermostatic
valve.)
The heating system controls must meet the requirements of the current issue of the Building Regulations.
For further information see: -
 The current issue of “Approved Document L1 – Conservation of fuel and power in dwellings”
 GIL 59, 2000 : Central heating system specification (CheSS)
 GPG 302, 2001: Controls for domestic central heating system and hot water. BRECSU.
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3.13. CONDENSATE DRAIN
A plastic drainpipe must be fitted to the boiler to allow discharge of condensate to the suitable drain.
A copper pipe is NOT suitable.
Condensate should, if possible, be discharged into the internal household drainage system. If this is not
practical, discharge can be made externally into the household drainage system or a purpose designed soak
away. See section 4 for further details.
Note: Condensate trap inside the boiler casing must be manually filled with water after installing the boiler
(i.e. before the first firing) and before commissioning the system.
3.14. WATER TREATMENT
In the case of an existing installation, the system MUST be thoroughly flushed before installing the
new boiler. Power Flushing is the preferred option for existing installations because all high
efficiency boilers tend to have smaller waterways than traditional boilers. A suitable system filter
(e.g. Spirovent SV3-025-T) fitted in the boiler return is STRONGLY recommended in existing systems.
For optimum performance after installation of the new system, the boiler and its associated central heating
system should also be flushed.
The flushing should be carried out in accordance with BS7593:1992 using cleaner such as Sentinel X300 or
X400 or Fernox Superfloc.
For long-term corrosion protection, after flushing, an inhibitor suitable for stainless steel heat exchangers
should be used. Refer to the current issue of BS5449 and BS7593 on the use of inhibitors in central heating
systems. The examples are Sentinel X100 and Fernox.
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