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mexico HE -

Installation & Servicing

DOCUMENT AMENDMENTS

Relevant Installation changes implemented in this book from Mod Level ............ A06 (Oct 06) to A07 (Jan 07)

Various Pages

Company name change.

Page 7, Optional Extra Kits

Addition of two new kits.

Page 9, Electrical Supply

Note for fan voltage.

Page 18, Frame 18 - Condensate Pipe Termination Configurations

Statement added with ref. to termination into a down pipe.

Page 18, Frame 18 - Condensate Pipe Termination Configurations

BS6798 recommends that a second trap and an air break are required where the siphon trap within the boiler is less than
75mm for configuration 3.

Page 29, Frame 38 - External Electrical Controls

Change to drawings re. position of "L1" and "L2".

Page 30, Frame 40 - Initial Lighting

Display code "P" added to "The Display" paragraph.

Page 47, Frame 73 - L...E... or H... E... (Board Error)

Addition of new flowchart.

Page 48, Frame 74 - L...A... (Overheat Error)

Note added.

Page 49, Frame 78 - H...4... Dry Fire Thermistor, H9/L9 (Flue Gas Overheat)

Wording of "thermistor" changed to read "dry fire thermistor".
Note added.

Page 50, Short List of Parts

Part number change to PCB Primary Control.

Users Guide, Page 2 - Important Notes

2 new bullet points added.

Users Guide, Page 2 - Operation

Addition of display code "P".

Ideal Stelrad Group reserve the right to vary specification without notice

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Installation & Servicing

GENERAL

Boiler Size

HE15

HE18

HE24

HE30

HE36

HE15-24

HE30-36

max

min

Input `Q'

Nett CV kW (Btu/h)

15.1 (51,500) 18.7 (63,800) 24.4 (83,300) 30.7 (104,700) 37.5 (128,000)

9.1 (31,000)

10.6 (36,200)

Gross CV kW (Btu/h)

16.8 (57,200) 20.7 (70,800) 27.1 (92,500) 34.0 (116,000) 41.6 (142,000)

10.1 (34,400)

11.8 (40,300)

Gas Consumption l/s (cu.ft/h)

0.43 (54.7)

0.53 (68.0)

0.70 (89.7)

0.88 (111.9)

1.07 (136.0)

0.26 (33.3)

0.30 (38.4)

Output `P' 70

c Mean Water temp. kW (Btu/h)

14.6 (50,000) 18.2 (62,300) 23.4 (80,000) 30.1 (102,700) 37.0 (126,200)

8.8 (30,000)

10.6 (36,200)

c Mean Water temp. kW (Btu/h)

15.5 (53,000) 19.2 (65,700) 25.1 (85,700) 32.8 (111,800) 39.8 (135,800)

9.6 (32,800)

11.4 (38,900)

Seasonal efficiency (SEDBUK) *

Band A

[90.4]%

[90.3]%

[90.2]%

[90.4]%

[90.7]%

NOx classification

Class 5

CAUTION.

To avoid the possibility of injury during the installation, servicing or cleaning of

this appliance, care should be taken when handling edges of sheet steel components.

Note.
Gas consumption is calculated using a calorific value of
38.7 MJ/m

(1038 Btu/ft

) gross or 34.9 MJ/m

(935 Btu/ft

)

nett. To obtain the gas consumption at a different calorific
value:-

a. For l/s - divide the gross heat input (kW) by the gross

C.V. of the gas (MJ/m

)

b. For ft

/h - divide the gross heat input (Btu/h) by the

gross C.V. of the gas (Btu/ft

)

Key to symbols

GB = United Kingdom IE = Ireland (Countries of destination)

PMS = Maximum operating pressure of water

A room sealed appliance designed for connection

via ducts to a horizontal or vertical terminal which
admits fresh air to the burner and discharges the
products of combustion to the outside through orifices
which, in this case, are concentric. The fan is up stream
of the combustion chamber.

An appliance designed for use on 2nd Family gas,
Group H only.

The value is used in the UK Government's Standard Assessment Procedure (SAP) for energy rating of dwellings.
The test data from which it has been calculated have been certified by a notified body.

Table 1 - General Data

Table 2 - Performance Data

Boiler Size

HE15

HE18

HE24

HE30

HE36

Gas Supply Connection

in. BSP

Flow and Return Connections

22mm copper 22mm copper

22mm copper 22mm copper 22mm copper

MAXIMUM Static Water Head

m (ft.)

30.5 (100)

MINIMUM Static Water Head

m (ft.)

0.45 (1.5)

Electrical Supply

230V - 50Hz

Power Consumption

38W

42W

Fuse Rating

External : 3A internal T3.15A L250V

Water Content

litre (gal.)

2.0 (0.44)

4.7 (1.0)

Packaged Weight

kg. (lb.)

54 (119)

68 (150)

Maximum Inst Weight

kg. (lb.)

47 (104)

67 (148)

Boiler Size

Height mm (in.)

850 (33.5)

Width mm (in.)

450 (17.7)

Depth mm (in.)

530 (20.9)

Gas Type

I2H-G20

Gas Supply Pressure

20mb

Flue duct diameter

mm (in.)

100 (4)

Flue horizontal duct length (max)

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GENERAL

CONTENTS

Air Supply ....................................................................... 9
Benchmark Commissioning Checklist ..................... 54
Boiler Clearances ......................................................... 6
Boiler Exploded Diagram ............................................ 14
Electrical Connections ............................................... 27
Electrical Supply ........................................................... 9
Electrical Systems Diagrams .................................... 29
Extension Ducts - Fitting ............................................. 22
Fault Finding ........................................................... 45-49
Flow Wiring Diagram .................................................. 28
Flue Fitting .............................................................. 19-26
Flue Installation Requirements .................................... 8
Gas Safety Regulations ................................................ 7
Gas Supply ..................................................................... 8
Initial Lighting .............................................................. 30
Installation ............................................................. 14-31
Mandatory Requirements ............................................. 7
Safe Handling ................................................................ 7
Servicing ................................................................ 32-44
Short List of Parts ....................................................... 50
Terminal Guards ............................................................ 8
Thermostatic Radiator valves .................................... 9
Water and Systems .............................................. 10-13
Water Connections .................................................. 6,17
Water Treatment ......................................................... 13
Wiring Diagrams ................................................... 27-29

mexico HE

Destination Countries:

GB, IE

NOTE TO THE INSTALLER: COMPLETE

THE BENCHMARK COMMISSIONING

CHECKLIST AND LEAVE THESE

INSTRUCTIONS WITH APPLIANCE

oiler

Page

Make and model ....................................................... 5
Appliance serial no. on data badge ...................... 14
SEDBUK No. % ......................................................... 4

Controls

Time and temperature control to heating ............. 29
Time and temperature control to hot water .......... 29
Heating zone valves .............................................. n/a
TRV's ......................................................................... 9
Auto bypass .............................................................. 9
Boiler interlock .......................................................... 9

For all boilers

Flushing to BS.7593 .............................................. 13
Inhibitor .................................................................. 13

Central heating mode
Heat input ................................................to be calculated

For assistance see Technical Helpline on the back page

Page

Burner operating pressure ...... measure and record
Central heating flow temp. ...... measure and record
Central heating return temp. ... measure and record

For combination boilers only

Scale reducer ......................................................... n/a

Hot water mode

Heat input ............................................................... n/a
Max. operating burner pressure .............................. n/a
Max. operating water pressure ............................. n/a
Cold water inlet temp ............................................ n/a
Hot water outlet temp. ........................................... n/a
Water flow rate at max. setting .............................. n/a

For condensing boilers only

Condensate drain .................................................. 17

For all boilers: complete, sign & hand over to customer

For GB, to comply with Building Regulations Part L1 (Part J in Scotland) the boiler should be fitted in accordance with the
manufacturer's instructions. Self-certification that the boiler has been installed to comply with Building Regulations can be
demonstrated by completing and signing the Benchmark Commissioning Checklist.

Natural Gas only

BENCHMARK COMMISSIONING CHECKLIST DETAILS

Boiler size

G.C. Appliance No.

PI No.

(Benchmark No.)

HE15

41-429-39

0063 BQ 3906

HE18

41-429-65

0063 BQ 3906

HE24

41-429-98

0063 BQ 3906

HE30

41-429-99

0063 BQ 3906

HE36

41-415-20

0063 BQ 3906

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GENERAL

All dimensions

in mm (in.)

mxhe7564

450 (17

)

225 (8

)

530 (21)

690
(27

)

467

(18

)

232 (9

)

288 (11

)

348 (13

)

449

(17

)

850

(33

)

Gas

Flow
Return

Flow

Return

BOILER SERVICE CONNECTIONS

1. This appliance is NOT suitable for

use in a direct hot water system.

2. If the boiler is to be used on a

sealed system an Overheat
Thermostat is fitted as standard.

FLOOR MOUNTING AND BOILER CLEARANCES

Flammable materials must not be placed in close proximity to the appliance.
Materials giving off flammable vapours must not be stored in the same room
as the appliance.

Floor mounting
1. The floor must be flat, level and of suitable load

bearing capacity.

2. The back of the boiler may be fitted up to the

wall.

Boiler clearances
The minimum overall dimensions of the space in
which the boiler is to operate and to facilitate
servicing are as shown
Additional space may be required for installation,
depending upon site conditions.
In addition a MINIMUM clearance of 450 mm (17

MUST be available at the front of the boiler, for
servicing.
Minimum front clearance when built behind a
concealing panel is 5mm (

").

mxhe7565

All dimensions in mm (in.)

Top clearance

(

)

(

)

(

)

Boiler

Flue

Overall Space Dim.

Model Length Depth Height Width
HE15

6 m

530

870

460

HE18

6 m

530

870

460

HE24

6 m

530

870

460

HE30

3 m

530

870

460

HE36

3 m

530

870

460

INTRODUCTION

The mexico HE range of boilers are fully automatically
controlled, floor standing, low water content, balanced flue,
fanned, condensing gas boilers. They have full modulating
central heating outputs of :
HE15 8.8 kW (30,000 Btu/h) to 14.6 kW (50,000 Btu/h).

HE18 8.8 kW (30,000 Btu/h) to 18.2 kW (62,300 Btu/h).

HE24 8.8 kW (30,000 Btu/h) to 23.4 kW (80,000 Btu/h).

HE30 10.6 kW (36,200 Btu/h) to 30.1 kW (102,700 Btu/h).

HE36 10.6 kW (36,200 Btu/h) to 37.0 kW (126,200 Btu/h).

Due to the very high efficiency of the boiler a plume of water
vapour will form at the flue terminal during operation depending
on external conditions.

The boiler casing is of white painted mild steel with the user
controls capable of being mounted remotely from the boiler, if
the option is required.

The heat exchanger is of cast aluminium.

Artificially softened water must NOT be used.

A pre-piping frame is provided to allow system and gas
connection to be made prior to boiler installation.

Note.
These boilers cannot be used on systems which include gravity
circulation.

The boilers are suitable for connection to fully pumped, open
vented or sealed water systems. Adequate arrangements for
completely draining the system by provision of drain cocks
MUST be provided in the installation pipework.

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Installation & Servicing

GENERAL

OPERATION

When there is a demand for heat, the heating system is supplied
at the selected temperature of between 30

C and 82

The boiler features a comprehensive diagnostic system which
gives detailed information on the boiler status when operating,
and performance of key components to aid commissioning and
fault finding.

SAFE HANDLING

This boiler may require 2 or more operatives to move it to its
installation site, remove it from its packaging base and during
movement into its installation location. Manoeuvring the boiler
may include the use of a sack truck and involve lifting, pushing
and pulling.
Caution should be exercised during these operations.
Operatives should be knowledgeable in handling techniques
when performing these tasks and the following precautions
should be considered:
·

Grip the boiler at the base.

Be physically capable.

Use PPE as appropriate, e.g. gloves, safety footwear.

During all manoeuvres and handling actions, every attempt
should be made to ensure the following unless unavoidable
and/or the weight is light.
·

Keep back straight.

Avoid twisting at the waist.

Avoid upper body/top heavy bending.

Always grip with the palm of the hand.

Use designated hand holds.

Keep load as close to the body as possible.

Always use assistance if required.

OPTIONAL EXTRA KITS

FLUING:

Flue Extension Ducts. (1000mm long)
HE15, 18 & 24 -up to 6m
HE30, & 36 - up to 3m
90

Elbow Kit (60/100 dia maximum no. per installation)

HE15, 18 & 24 -up to 4 elbows
HE30, & 36 - up to 2 elbows
45

Elbow Kit (60/100 dia maximum no. per installation)

HE15, 18 & 24 -up to 4 elbows
HE30, & 36 - up to 2 elbows
Roof Flue Kit (60/100)
HE15, 18 & 24 -up to a maximum of 8m
HE30, & 36 -up to a maximum of 5m
Pitched Roof Tile (for roof flue kit)
Flat Roof Tile (for roof flue kit)
Vertical Flue Adaptor
Vertical Outlet Flue Kit with Elbow (60/100)
HE15, 18 & 24 - to a maximum length of 6m
HE30, & 36 - to a maximum length of 3m
Flue Finishing Kit
High Level Flue Outlet Kit
Flue Deflector Kit

OTHER OPTIONAL KITS:

Remote User Control Kit
Condensate Pump Kit
Concealment Panel Kit
RS Boiler Terminal Wall Plate Kit

SAFETY

Current Gas Safety (Installation and Use) Regulations or
rules in force.
The appliance is suitable only for installation in GB and IE and
should be installed in accordance with the rules in force.
In GB, the installation must be carried out by a CORGI
Registered Installer. It must be carried out in accordance with
the relevant requirements of the:
·

Gas Safety (Installation and Use) Regulations

The appropriate Building Regulations either The Building
Regulations, The Building Regulations (Scotland), Building
Regulations (northern Ireland).

The Water Fittings Regulations or Water bye-laws in
Scotland.

The Current I.E.E. Wiring Regulations.

Where no specific instructions are given, reference should be
made to the relevant British Standard Code of Practice.
In IE, the installation must be carried out by a Competent
Person and installed in accordance with the current edition of
I.S.813 "Domestic Gas Installations", the current Building
Regulations and reference should be made to the current ETCI
rules for electrical installation.
Detailed recommendations are contained in the following British
Standard Codes of Practice:
BS. 5440:1

Flues (for gas appliances of rated input not
exceeding 70 kW).

BS. 5440:2

Ventilation (for gas appliances of rated input not
exceeding 70 kW).

BS. 5449

Forced circulation hot water systems.

BS. 5546

Installation of gas hot water supplies for
domestic purposes (2nd Family Gases).

BS. 6798

Installation of gas fired hot water boilers of rated
input not exceeding 60 kW.

BS. 6891

Low pressure installation pipes.

Health & Safety Document No. 635
The Electricity at Work Regulations, 1989.
The manufacturer's notes must NOT be taken, in any way, as
overriding statutory obligations.
IMPORTANT. These appliances are CE certificated for safety
and performance. It is, therefore, important that no external
control devices, e.g. flue dampers, economisers etc., are
directly connected to these appliances unless covered by these
Installation and Servicing Instructions or as otherwise
recommended by Ideal Stelrad Group in writing. If in doubt
please enquire.
Any direct connection of a control device not approved by Ideal
Stelrad Group may invalidate the certification and the normal
appliance warranty. It could also infringe the Gas Safety
Regulations and the above regulations.

SAFE HANDLING OF SUBSTANCES

Care should be taken when handling the boiler insulation
panels, which can cause irritation to the skin. No asbestos,
mercury or CFCs are included in any part of the boiler or its
manufacture.

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GENERAL

LOCATION OF BOILER

The boiler must be installed on a flat and level floor, capable of
adequately supporting the weight of the boiler and any ancillary
equipment.
The boiler may be fitted on a combustible floor. Insulation is
not necessary, unless required by the local authority.
For electrical safety reasons there must be no access from the
back of the boiler.
The boiler must not be fitted outside.
Timber Framed Buildings
If the boiler is to be fitted in a timber framed building it should
be fitted in accordance with the Institute of Gas Engineering
document IGE/UP/7:1998.
Bathroom Installations
This appliance is rated IP20.
The boiler may be installed in any room or internal space,
although particular attention is drawn to the requirements of the
current IEE (BS.7671) Wiring Regulations and, in Scotland, the
electrical provisions of the building regulations applicable in
Scotland, with respect to the installation of the boiler in a room
or internal space containing a bath or shower. For Ireland
reference should be made to the current ETCI rules for
electrical installations and I.S.813:2002.
If the appliance is to be installed in a room containing a bath or
shower then, providing water jets are not going to be used for
cleaning purposes (as in communal baths/showers), the
appliance can be installed in Zone 3, as detailed in BS.7671.

Compartment Installations
A compartment used to enclose the boiler should be designed
and constructed specially for this purpose.
An existing cupboard or compartment may be used, provided
that it is modified for the purpose.
In both cases details of essential features of cupboard /
compartment design, including airing cupboard installation,
are to conform to the following:

BS. 6798. (No cupboard ventilation is required - see "Air
Supply" for details).
The position selected for installation MUST allow adequate
space for servicing in front of the boiler.
For the minimum clearances required for safety and
subsequent service see Frame 2.
This position MUST also permit the provision of a
satisfactory flue termination.
Boiler may be fitted under a worktop/surface. Boiler can be
fitted behind a kitchen cupboard door without need for
ventilation.

GAS SUPPLY

The local gas supplier should be consulted, at the installation
planning stage, in order to establish the availability of an
adequate supply of gas. An existing service pipe must NOT be
used without prior consultation with the local gas supplier.
The boiler MUST be installed on a gas supply with a governed
meter only.

A gas meter can only be connected by the local gas supplier or
by a CORGI registered engineer. In IE by a Competent Person.

An existing meter should be checked, preferably by the gas
supplier, to ensure that the meter is adequate to deal with the
rate of gas supply required.

N.B.

The principle of the 1:1 gas valve ensures that the

mexico HE range is able to deliver their full output at inlet
pressures down to 14mb. However if dynamic pressures
below 20mb are experienced ensure this is adequate for ALL
other gas appliances in the property.

IMPORTANT.
Installation pipes MUST be fitted in accordance with BS. 6891.
In IE refer to I.S.813:2002. Pipework from the meter to the boiler
MUST be of an adequate size, i.e. no longer than 20m and not
less than 15mm O.D.
The complete installation MUST be tested for gas soundness
and purged as described in the above code.

FLUE INSTALLATION

Pluming will occur at the terminal so terminal positions which
would cause a nuisance should be avoided.
The flue must be installed in accordance with the
recommendations of BS.5440-1:2000. In IE refer to I.S.813:2002.
The following notes are intended for general guidance.
1. The boiler MUST be installed so that the terminal is exposed

to external air.

2. It is important that the position of the terminal allows the free

passage of air across it at all times.

3. Minimum acceptable spacing from the terminal to

obstructions and ventilation openings are specified in Table 3.

4. Where the lowest part of the terminal is fitted less than 2m

(6'6") above a balcony, above ground or above a flat roof to
which people have access, then the terminal MUST be
protected by a purpose designed guard.
Ensure that the guard is fitted centrally.
Terminal guards are available from boiler suppliers. Ask for
TFC Flue Guard Model No. K6 (round plastic-coated). In
case of difficulty contact:
Grasslin (UK) Ltd.

Tel. +44(0) 01732 359 888

Tower House, Vale Rise

Fax. +44(0) 01732 354 445

Tonbridge. kent TN9 1TB

www.tfc-group.co.uk

Flue Terminal Positions

Min. Spacing*

1. Directly below or alongside an opening

window, air vent or other ventilation opening.

300mm (12")

2. Below guttering, drain pipes or soil pipes.

25mm ( 1")*

BS5440-1 2000

75mm (3")

3. Below eaves.

25mm (1")*

BS5440-1 2000

200mm (8")

4. Below balconies or a car port roof.

25mm (1")*

BS5440-1 2000

200mm (8")

5. From vertical drain pipes or soil pipes.

25mm (1")*

BS5440-1 2000

150mm (6")

6. From an internal or external corner or to a

25mm (1")*

boundary along side the terminal.

BS5440-1 2000

300mm (12")

7. Above adjacent ground, roof or balcony level.

300mm (12")

8. From a surface or a boundary facing the terminal.

600mm (24")

9. From a terminal facing a terminal.

1,200mm (48")

10. From an opening in a car port

(e.g. door or window) into dwelling.

1,200mm (48")

11. Vertically from a terminal on the same wall.

1,500mm (60")

12. Horizontally from a terminal on the wall.

300mm (12")

Vertical Terminals

13. Above the roof pitch with roof slope of all angles. 300mm (12")

Above flat roof.

300mm (12")

14. From a single wall face.

600mm (24")

From corner walls.

1000mm (40")

Twin Flue Applications

15. Centre distance between air inlet and flue

outlet ducts.

120mm (5")

Table 3 - Balanced Flue Terminal Position

* Only one reduction down to 25mm is allowable per installation
otherwise BS5440-1 2000 dimensions must be followed.

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Installation & Servicing

GENERAL

5. The flue assembly shall be so placed or shielded as to

prevent ignition or damage to any part of any building.

6. The air inlet/products outlet duct and the terminal of the

boiler MUST NOT be closer than 25mm (1") to combustible
material. Detailed recommendations on the protection of
combustible material are given in BS.5440-1:2000. In IE
refer to I.S.813:2002.

IMPORTANT

It is absolutely ESSENTIAL to ensure, in practice, that products
of combustion discharging from the terminal cannot re-enter the
building or any other adjacent building through ventilators,
windows, doors, other sources of natural air infiltration, or forced
ventilation / air conditioning.

If this should occur the appliance MUST be turned OFF, labelled
as 'unsafe' until corrective action can be taken.

TERMINAL

The terminal assembly can be adapted to accommodate
various wall thicknesses. Refer to Frame 19.

AIR SUPPLY

It is NOT necessary to have a purpose-provided air vent in the
room or internal space in which the boiler is installed. Neither
is it necessary to ventilate a cupboard or compartment in which
the boiler is installed, due to the low surface temperatures of
the boiler casing during operation; therefore the requirements
of BS 6798, Clause 12, and BS 5440:2 may be disregarded. In
IE the requirements of I.S.813:2002 may be disregarded.

WATER CIRCULATION SYSTEM

IMPORTANT.

A minimum length of 1 metre of copper pipe MUST be fitted to
both flow and return connections from the boiler before
connection to any plastic piping.

For boiler outputs greater than 60,000 btu/h (17.6 kW) the flow
and return pipework should be connected in 28mm pipe.

For the types of system and correct piping procedure see
Frames 1, and 3 to 8.

The central heating system should be in accordance with
BS.6798 and, in addition, for smallbore and microbore
systems, BS.5449.

WATER TREATMENT - see Frame 9

The hot water storage cylinder MUST be of the indirect type and
should preferably be manufactured of copper.

Graph 1 - Water flow rate and pressure loss

Single feed, indirect cylinders are not recommended and MUST
NOT be used on sealed systems.

The appliances are NOT suitable for gravity central heating nor
are they suitable for the provision of gravity domestic hot water.

The hot water cylinder and ancillary pipework, not forming part
of the useful heating surface, should be lagged to prevent heat
loss and any possible freezing - particularly where pipes run
through roof spaces and ventilated underfloor spaces.

The boiler must be vented.

The hydraulic resistance of the boilers, at MAXIMUM OUTPUT,
is shown in Graph 1.

BOILER CONTROL INTERLOCKS

Ideal Stelrad Group recommend that heating systems utilising
full thermostatic radiator valve control of temperature in
individual rooms should also be fitted with a room thermostat
controlling the temperature in a space served by radiators not
fitted with such a valve as stated in BS. 5449.

Central heating systems controls should be installed to ensure
the boiler is switched off when there is no demand for heating
or hot water.

When thermostatic radiator valves are used, the space heating
temperature control over a living / dining area or hallway having
a heating requirement of at least 10% of the boiler heat output
should be achieved using a room thermostat, whilst other
rooms are individually controlled by thermostatic radiator
valves. However, if the system employs thermostatic radiator
valves on all radiators, or two port valves without end switches,
then a bypass circuit must be fitted with an automatic bypass
valve to ensure a flow of water should all valves be in the
closed position.

ELECTRICAL SUPPLY

WARNING.
This appliance must be earthed.
Wiring external to the appliance MUST be in accordance with
the current I.E.E. (BS.7671) Wiring Regulations and any local
regulations which apply. For Ireland reference should be made
to the current ETCI rules for electrical installations.
The point of connection to the mains should be readily
accessible and adjacent to the boiler.
N.B. THE FAN VOLTAGE IS 325V DC.

CONDENSATE DRAIN

- Refer to Frames 13, 15 and 18

A condensate drain is provided on the boiler. This drain must
be connected to a drainage point. All pipework and fittings in
the condensate drainage system MUST be made of plastic - no
other materials may be used.

IMPORTANT.
Any external runs must be insulated.
The drain outlet on the boiler is standard 21.5mm (

3/4

overflow pipe.
A condensate pump kit is available if required which may be
fitted inside the boiler casing.

0.00

0.50

1.00

1.50

2.00

2.50

Resistance (metres water)

Flow Rate (l/min)

HE15, 18 & 24
HE30 & 36

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Installation & Servicing

GENERAL

OPEN VENT SYSTEM REQUIREMENTS

SCHEMATIC PIPEWORK AND SYSTEM BALANCING

The boiler does not normally need a bypass but at least some
radiators on the heating circuit, of load at least 10% of the
minimum boiler output, must be provided with twin lockshield
valves so that this minimum heating load is always available
(see footnote re. thermostatic radiator valves).

Return & flow
connections
load 30 - 60 = 22 mm
load 70 - 80 = 28 mm

Balancing

1. Set the programmer to ON for both CH and HW.

Turn the cylinder thermostat down. Close the
manual or thermostatic valves on all radiators,
leaving the twin lockshield valves (on the radiators
referred to above) in the open position. Turn up the
room thermostat and adjust these lockshield valves
to give boiler flow and return temperatures not more
than 20

C apart. These valves should now be left

as set.

2. Open all manual or thermostatic radiator valves and

adjust the lockshield valves on remaining radiators
to give around 11

C temperature drop at each

radiator.

3. Turn up the cylinder thermostat and adjust the

cylinder balancing valve so that the cylinder
achieves a maximum flow consistent with adequate
flow to the radiators. Check that with only the
domestic hot water loop in circuit a differential
temperature of 20

C across the boiler is not

exceeded.

4. Adjust room and cylinder thermostats and

programmer to NORMAL settings.

The system should be vented directly off the boiler flow pipe,
as close to the boiler as possible. The cold feed entry
should be inverted and MUST be positioned between the
pump and the vent, and not more than 150mm (6") away
from the vent connection.

Note. Combined feed and vent pipes may also be fitted.

There should be a minimum height 450mm (18") of open
vent above the cistern water level. If this is not possible refer
to Frame 5. The vertical distance between the highest point
of the system and the feed/expansion cistern water level
MUST not be less than 450 mm (18"). The pump must be
fitted on the flow side of the boiler.

A suitable pump is a domestic circulator capable of
providing a maximum 11

C (20

F) temperature differential

across the boiler with the whole of the heating circuit open
(e.g. Grundfos UPS 15/50, 15/60 or equivalent). With the
minimum flow circuit allowed by the controls the differential
must not exceed 25

C. (18

C for the HE15)

The vertical distance between the pump and feed/expansion
cistern MUST comply with the pump manufacturer's
minimum requirements, to avoid cavitation. Should these
conditions not apply either lower the pump position or raise
the cistern above the minimum requirement specified by
Ideal Stelrad Group. The isolation valves should be fitted as
close to the pump as possible.

cla7647

cla7648

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mexico HE -

Installation & Servicing

GENERAL

Non-return

valve

Automatic

air vent

Hose unions

Additional

stop valve

Hosepipe

(disconnect

after filling)

Double check valve

assembly

(note direction of flow)

Temporary hose

(disconnect

after filling)

cla7650

Hose

connector

Note. The pump manufacturers' minimum requirements must be complied with.

LOW HEAD AND LARGE SYSTEMS WITH EXTENSIVE PIPE RUNS - OPEN VENT

All dimensions in mm (in.).
NB. Imperial dimensions are approximate

Flow

Return

cla7649

SEALED SYSTEM REQUIREMENTS

This arrangement is useful for large systems where
radiators at the extremities are difficult to vent. This
can lead to pumping over with conventional feed and
vent arrangements.

The following conditions MUST be observed:

1. The top of the automatic air vent must be below

the cold water level.

2. The static water level (cold) must be at least

200mm above the top of the horizontal flow pipe,
fitted as shown. The vent connection MUST NOT
be made immediately off the top of the boiler as
venting is made less efficient.

3. The maximum practical length of 22mm cold feed

pipe should be used in order to reduce the
effective volume of hot system water expanding
into the feed/expansion cistern to a minimum.

a. A non-adjustable preset lift pressure not exceeding

3bar (45lb/in

b. A manual testing device.

c. Provision for connection of a discharge pipe.

The valve or discharge pipe should be positioned so
that the discharge of water or steam cannot create a
hazard to the occupants of the premises or cause
damage to electrical components and wiring.

3. Pressure Gauge

A pressure gauge covering at least the range 0-4 bar
(0-60 lb/in

) must be fitted to the system. The gauge

should be easily seen from the filling point and should
preferably be connected at the same point as the
expansion vessel.

Notes.
a. The method of filling, refilling, topping up or flushing

sealed primary hot water circuit from the mains via a
temporary hose connection is only allowed if
acceptable to the local water
authority.

b. When installing the filling device, it

must be connected as shown to
fully comply with the water
regulations. This may involve the
fitting of an additional WRAS
approval isolator valve to the
mains supply.

1. General

a. The installation must comply with the

requirements of BS. 6798 and BS. 5449.

b. The installation should be designed to work with

flow temperatures of up to 82

c. All components of the system, including the heat

exchanger of the indirect cylinder, must be
suitable for a working pressure of 3 bar (45lb/in

)

and temperature of 110

C. Care should be taken

in making all connections so that the risk of
leakage is minimised.

2. Safety Valve

A spring loaded safety valve complying with the
relevant requirements of BS. 6759 must be fitted in
the flow pipe as close to the boiler as possible and
with no intervening valve or restriction. The valve
should have the following features:

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mexico HE -

Installation & Servicing

GENERAL

SEALED SYSTEM REQUIREMENTS - continued

pressure. The cold feed pipe from the cistern should
include a non-return valve and a stop valve with an
automatic air vent connected between them, the stop
valve being located between the system and the
automatic air vent. The stop valve may remain open
during normal operation of the system if automatic
water make-up is required.

b. Through a self-contained unit comprising a cistern,

pressure booster pump (if required) and, if necessary,
an automatic pressure reducing valve and flow
restrictor. The cistern should be supplied through a
temporary connection from a service pipe or cold
water distributing pipe.
This unit may remain permanently connected to the
heating system to provide limited automatic water
make-up. Where the temporary connection is supplied
from a service pipe or distributing pipe which also
supplies other draw-off points at a lower level then a
double check valve shall be installed upstream of the
draw-off point.

c. Through a temporary hose connection from a draw-off

tap supplied from a service pipe under mains
pressure. Where the mains pressure is excessive a
pressure reducing valve shall be used to facilitate
filling.

The following fittings shall form a permanent part of
the system and shall be fitted in the order stated:

A stop valve complying with the requirements of
BS. 1010, Part 2 (the hose from the draw-off tap shall
be connected to this fitting).
A test cock.
A double check valve of an approved type.

· Thoroughly flush out the whole of the system with

cold water, without the pump in position.

· With the pump fitted, fill and vent the system until the

pressure gauge registers 1.5 bar (21.5lb/in

Examine for leaks.

· Check the operation of the safety valve by manually

raising the water pressure until the valve lifts. This
should occur within ± 0.3 bar (± 4.3lb/in

) of the

preset lift pressure.

· Release water from the system until the initial system

design pressure is reached.

· Light the boiler and heat the system to the maximum

working temperature. Examine for leaks.

· Turn off the boiler and drain the system while still hot.

· Refill and vent the system.

· Adjust the initial pressure to the required value.

4. Expansion Vessel

a. A diaphragm type expansion vessel must be

connected to a point close to the inlet side of the
pump, the connecting pipe being not less than 15 mm
(

1/2

" nominal) size and not incorporating valves of

any sort.<