Glow-worm Micron 70FF User Manual

2000225229C.04.05

Instructions for Use

Installation and Servicing

To b e l e f t w i t h t h e u s e r

Micron

70FF

G.C. No. 41-047-50

Fanned Flue Boiler

This is a Cat I2H Appliance

Reference in these instructions to British Standards and Statutory Regulations/Requirements apply only to the United Kingdom.

For Ireland the current edition of I.S.813 "Domestic Gas Installations" must be used.

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.

Guarantee Registration

7319

Thank you for installing a new Glow-worm appliance in your home.

Glow-worm appliances' are manufactured to the very highest standard so we are pleased to offer our customers' a Comprehensive First Year 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 by covering the cost of:

					REGISTER YOUR GLOW-WORM APPLIANCE
	All replacement parts
		All labour charges			FOR 1ST YEAR GUARANTEE PROTECTION
					CALL 0800 073 2142
		All call-out charges
						Glow-worm,
				Tel: [phone]		Nottingham Road, Belper, Derbyshire. DE56 1JT
				Fax: [phone]		General/Sales enquiries:
						Tel: [phone] Fax: [phone]
						www.glow-worm.co.uk

Important Information

Testing and Certification

This boiler is tested and certificated to EN483 for safety and performance. It is therefore important that no alteration is made to the boiler, without permission, in writing, from Glow-worm.

Any alteration not approved by Glow-worm, could invalidate the certification, boiler warranty and may also infringe the current issue of the Statutory Requirements.

CE Mark

This boiler meets the requirements of Statutory Instrument No. 3083 The boiler (Efficiency) Regulations, and therefore is deemed to meet the requirements of Directive 92/42/EEC on the efficiency requirements for new hot water boilers fired with liquid or gaseous fuels.

Type test for purposes of Regulation 5 certified by: Notified body 0086.

Product/production certified by: Notified body 0086.

The CE mark on this appliance shows compliance with:

1.Directive 90/396/EEC on the approximation of the Laws of the Member States relating to appliances burning gaseous fuels.

2.Directive 73/23/EEC on the harmonization of the Laws of the Member States relating to the electrical equipment designed for use within certain voltage limits.

3.Directive 89/336/EEC on the approximation of the Laws of the Member States relating to electromagnetic compatibility.

INFORMATION FOR THE INSTALLER AND SERVICE ENGINEER.

Under Section 6 of The Health and Safety at Work Act 1974, we are required to provide information on substances hazardous to health.

Insulation pads and Glass yarn.

These can cause irritation to skin, eyes and the respiratory tract. If you have a history of skin complaint you may be susceptible to irritation. High dust levels are usual only if the material is broken. Normal handling should not cause discomfort, but follow normal good hygiene and wash your hands before eating, drinking or going to the lavatory. If you do suffer irritation of the eyes or severe irritation to the skin seek medical attention.

SPARE PARTS

REMEMBER: When replacing a part on this appliance, use only spare parts that you can be assured conform to the safety and performance specification that we require. Do not use reconditioned or copy parts that have not been clearly authorised by Glow-worm.

	CONTENTS	DESCRIPTION	SECTION	PAGE No.
	INSTRUCTIONS	Introduction		3
	FOR USE	Lighting the Boiler		3
	INSTALLATION	General Data	1	4
		Flue and Ventilation	2	7
	INSTRUCTIONS	Water Systems	3	8
		Flue and Appliance Preparation	4	10
		Boiler Installation	5	13
		Commissioning	6	17
		Instructions to the User	7	19

	SERVICING	Servicing	8	20
		Fault Finding	9	21
	INSTRUCTIONS
		Replacement of Parts	10	25
		Spare Parts	11	28

2000225229C

2

Instructions for Use

Introduction

Please read these instructions and follow them carefully for the safe and economical use of your boiler.

The Micron series are fanned flue boilers designed to provide central heating and indirect domestic hot water.

The boiler is fully automatic in operation having only one user control, the temperature control.

WARNING: It is important that the case is not disturbed or removed other than for servicing by a competent person.

Gas Leak or Fault

Turn off the gas emergency control valve immediately. Eliminate all sources of ignition, i.e.smoking, blowlamps, hot air guns etc. Do not operate electrical lights or switches either on or off. Open all doors and windows, ventilate the area.

Electrical Supply Failure

Failure of the electrical supply will cause the burner to go out. Should this occur, operation of the appliance will normally resume after the electrical supply is restored.

If the boiler does not relight after an electrical supply failure the overheat safety cutoff device may need resetting, as indicated by illuminated reset light. Open the controls cover and turn temperature control to “0” (anticlockwise) and then back to original position, refer to diagram 9.1.

NOTE: If the boiler is switched OFF, manually, wait at least 30 seconds before switching on again.

Safety Temperature Limiter

IfthesafetyTemperatureLimiteroperatesonanyotheroccasion than an electrical supply failure, follow the procedure as in “Electrical Supply Failure”. If the overheat operates again, turn theapplianceoffandcontactyourinstallation/servicingcompany.

Protection Against Freezing.

If the boiler is to be out of use for any long period of time during severe weather conditions we recommend that the whole of the system, including the boiler, be drained off to avoid the risk of freezing up. Make sure that, if fitted, the immersion heater in the cylinder is switched off. Alternatively, there is a built-in frost protection which will cause the boiler when it is switched off at the control knob to operate in the event of the water temperature in the boiler dropping to 6oC or 7oC. The boiler will switch off again when the temperature of the water in the boiler reaches about 15oC. This will only protect the central heating system if the external controls are set so that the pump runs continuously, that is they are calling for heat.

NOTE: The frost protection will not operate if the electrical supply is turned off.

Maintenance

To ensure the continued efficient and safe operation of the boiler it is recommended that it is checked and serviced as necessary at regular intervals. The frequency of servicing will depend upon the particular installation conditions and usage, but in general once a year should be enough.

If this appliance is installed in a rented property in the UK 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.

It is the law that any servicing is carried out by a competent person.

To obtain service, please call your installer or Glow-worm’s own Service Organisation using the telephone number given on the front cover of these instructions.

Please be advised that the ‘Benchmark’ logbook should be completed by the installation engineer on completion of commissioning and servicing.

All CORGI Registered Installers carry a CORGI ID card, and have a registration number. Both should be recorded in your boilerLogbook. YoucancheckyourinstallerisCORGIregistered by calling CORGI direct on :- 01256 372300.

Cleaning

WARNING: This appliance contains metal parts (components) and care should be taken when handling and cleaning, with particular regard to edges.

Clean the casing occasionally by wiping it over with a damp cloth or dry polishing duster.

Do not use an abrasive cleaner.

To Turn the Boiler On

Do not operate the boiler wthout water.

SEALED SYSTEMS (only)

The pressure gauge should show at least 0.7bar, anything less than this figure could indicate a leak and you MUST contact your installation/servicing company.

ALL SYSTEMS

Turn the electrical supply on to the boiler and check that all remote controls are calling for heat.

Open the controls cover, see diagram 9.1.

Check also that the programmer (if fitted) is in the “ON” mode.

Turn the control knob clockwise to any position between "O" and MAX. The maximum temperature setting is approx. 82OC (180OF), see diagram 9.1.

The boiler lighting operation is now automatic as follows:

The fan will operate for a short period prior to the start of the ignition sparks. The gas valve solenoids will open and the burner will light. This is shown by the "Burner Lit" LED on the control panel lighting up.

The burner will remain alight until switched off by the control thermostat, any remote control or the programmer.

NOTE: If the boiler is switched OFF, by hand, wait at least 30 seconds before switching on again.

When the boiler switches off, the boiler will go out.

The automatic lighting sequence will operate again when heat is required.

Shut the controls cover.

It should be noted that this is a fan flue appliance and fan operation may be heard.

To Turn the Boiler Off

For short periods, turn the control knob anti-clockwise to “0” Off. To relight, turn the control knob to any position between “0” and “MAX”.

For longer periods, turn the control knob fully anti-clockwise to “0” Off and switch off the electrical supply to the boiler.

To relight follow the lighting sequence given above.

Optional Programmer

A programmer is available, which will automatically switch your central heating system on and off once or twice a day at whatever times you choose.

NOTE: If the programmer is manually switched on then off when the boiler is cold, the boiler may continue to operate for about 30 seconds before switching off.

3	2000225229C

Installation - 1 General

A

B

D

L7059

E

E

J

TOP, SIDE

PUMPED RETURN

PUMPED FLOW

FLUE

Q

OPTION

H

K

C

C

WATER CONNECTIONS

G

22mm COPPER PIPE

F

GAS CONNECTIONS

N

RC1/

(1/ in BSPT)

2

2

REAR FLUE

OPTION

P

M

MODEL

A

B

C

D

E

F

G

H

J

K

L

M

N

P

Q

70FF

298

75

122

370

146

556 67.5

85

115

128

126

156

100

157

40

92

108

STD/EXD. EASYFIT

STD/EXD. EASYFIT

All dimensions are given in millimetres

Diagram 1.1

IMPORTANT NOTICE

This boiler is for use on Natural Gas (G20) as distributed in the United Kingdom and Ireland and cannot be used on any other gas. This boiler must be installed by a competent person

ONLY.

This boiler can be used on open vented or sealed water systems.

Domestic hot water must be provided by pumped circulation.

Wherever possible, all materials, appliances and components used shall comply with the requirements of applicable British Standards.

Where no British Standards exists, materials and equipment should be fit for their purpose and of suitable quality and workmanship.

I.S.813 “Domestic Gas Installations”, the current Building Regulations and reference should be made to the current ETCI rules for Electrical Installation.

In GB the following Codes of Practice apply:

BS4814, BS6798, BS5440 Part 1 and 2, BS5546 Part 1, BS5449, BS6891, BS6700, BS7074 Part 1 and 2, BS7593, BS7671.

In IE: I.S.813, BS5546, BS 5449, BS 7074, BS 7593.

Manufacturer’s instructions must not be taken as overriding statutory requirements.

NOTE: For further information, see the current issue of the Building Regulations, approved document L1 (in the UK) and the references:

1) GIL 59, 2000: Central heating system specification (CheSS) and

Sealed Components

Under no circumstances must the User interfere with or adjust sealed parts.

Sheet Metal Parts

WARNING: When installing or servicing this boiler care should betakenwhenhandlingsheetmetalparts,toavoidanypossibility of personal injury.

1.1 Statutory Requirements

In GB the installation of the boiler must be carried out by a competent person as described in the following regulations:

The manufacturer’s instructions supplied.

The Gas Safety (Installation and Use) Regulations.

The appropriate Buildings Regulations either The Building Regulations, The Building Regulations (Scotland),The Building Regulations (Northern Ireland).

The Water Fittings Regulations or Water byelaws in Scotland.

The Health and Safety at Work Act, Control of Substances Hazardous to Health (COSHH).

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

2) GPG 302, 2001: Controls for domestic central heating system and hot water. BRECSU.

1.2 Data

See diagrams 1.1, 1.2 and Table 1. All dimensions are given in millimetres

The Seasonal Efficiency Domestic Boilers UK (SEDBUK) is 78.2%.

ThevalueisusedintheUKGovernment’sStandardAssessment Procedure (SAP) for energy rating of dwellings. The test data from which it has been calculated have been certified by B.S.I.

1.3 Range Rating

This boiler is range rated and may be adjusted to suit individual systemrequirements,refertodiagram1.2fordatalabelposition, ratings and settings.

2000225229C

4

1 General

1.4 Gas Supply

The gas installation shall be in accordance with the relevant standards.

In GB this is BS6891.

In IE this is the current edition of I.S.813 "Domestic Gas Installations".

The supply from the governed meter must be of adequate size to provide a steady inlet working pressure of 20mbar (8in wg) at the boiler.

On completion test the gas installation for soundness using the pressure drop method, purge in accordance with the above standard.

9444

PMS = 3.0 bar, is: Maximum water-side operating pressure.

The appliance flue type is a C12 and C32. This refers to a concentric flue where the fan is downstream of the heat exchanger. The C12 is a horizontal flue termination and the C32 is a vertical flue termination.

7316

DATA

LABEL

Diagram 1.2

TABLE 1.

	TOTAL DRY WEIGHT	49.2 kg
	(Including Terminal)
	LIFT WEIGHT	40.3 kg
	WATER CONTENT	3.35 litre (0.74 gallon)
	GAS CONNECTION	Rc 1/ in.
		2
	ELECTRICITY RATING	81W
		Internal fuse Type T3.15A
	WATER CONNECTION	2x22mm copper pipes from
		back of case
	ELECTRICITY SUPPLY	230V~50Hz, fused 3A
	DATA LABEL	Top left of inside of case

1.5 Electrical Supply

WARNING: This boiler must be earthed.

All system components shall be of an approved type and shall be connected in accordance with the current issue of BS7671 and any applicable local regulations.

External wiring must be correctly earthed, polarised and in accordance with the relevant standards.

In GB this is BS6891.

In IE this is the current edition of I.S.813 "Domestic Gas Installations".

Connection of the boiler and system controls to the mains supply must be through a common isolator and must be fused 3A, maximum. This method of connection must be by a fused double pole isolating switch, with a minimum contact separation of 3mm on both poles. The switch should be readily accessible and preferably adjacent to the appliance. It should supply the appliance only and be easily identifiable as so doing.

Alternatively, an unswitched shuttered socket outlet and 3A fused 3 pin plug, both to the current issue of BS1363 may be used provided that they are not used in a room containing a bath or shower.

Wiring to the boiler must be PVC 850C insulated cable, not less than 0.75mm2 (24/0.20mm).

1.6 Contents of Packaging

The boiler is delivered in two or more packs, depending on flue system, refer to diagram 4.1 for contents.

1.7 Water System

This boiler may be fitted to an open vented or a sealed water system.

1.8 Draining Tap

System

A draining tap must be provided at the lowest points of the system which will allow the entire system and hot water cylinder to be drained.

Draining taps should be to the current issue of BS2879.

Boiler

A draining point is fitted at the bottom right hand side of the heat exchanger.

When draining is required, cover the controls to avoid water damage.

If required remove the combustion chamber front cover to improve access.

1.9 Safety Valve

A safety valve need not be fitted to an open vented system.

5	2000225229C

1 General

6mm

6mm

10mm FROM A NON-PERMANENT

320mm FROM A PERMANENT

*190mm with Easyfit top flue fitted,

*160mm with standard/extended top flue fitted, 20mm without top flue fitted

Increased top clearance is required if flow pipe enters from below to permit access to air vent.

MINIMUM CLEARANCES FROM WALLS, CEILING, FLOOR, CUPBOARD,
WORKTOPS AND INFLAMMABLE MATERIALS	Diagram 1.3

1.10 Location

This boiler is not suitable for outdoor installation.

The boiler may be installed in any room, although particular attention is drawn to the requirements of BS7671 with respect to the installation of a boiler in a room containing a bath or shower. Any electrical switch should be so positioned that it cannot be touched by a person using the bath or shower. The electrical provisions of the Building Standards (Scotland) Regulations apply to such installations in Scotland.

This boiler is suitable for installation in bathroom zones 2 and 3.

In GB this is the current I.E.E. WIRING REGULATIONS and BUILDING REGULATIONS.

In IE reference should be made to the current edition of I.S.813 "Domestic Gas Installations" and the current ETCI rules.

The boiler must be mounted on a flat wall which is sufficiently robust to take its total weight.

The boiler may be fitted to a wall made of combustible material.

1.11 Boiler Clearances

Refer to diagram 1.3.

This boiler must be positioned so that at least the minimum operational and servicing clearances are provided.

Additional clearances may be required for installation.

If fixtures are positioned next to the boiler ensure access is provided for pipework installation.

At least a minimum clearance of 320mm from a permanently fixed surface must be left in front of the boiler for servicing, see diagram 1.3.

1.12 Room Ventilation

The boiler is room sealed and does not require the room or space containing it to have permanent air vents.

1.13 Boilers in a Compartment

Where the installation of the boiler will be in an unusual position, the current issue of BS6798 gives detailed guidance on these requirements.

An existing cupboard or compartment modified for the purpose may be used, providing minimum clearances are maintained. Details of essential requirements for cupboard or compartment design are given in the current issue of BS6798.

The doorway opening should be of sufficient size to allow for easy removal of the boiler.

Where the boiler is fitted in a cupboard or compartment, permanent ventilation is not required.

1.14 Timber Frame Building

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 seek advice from the local gas undertaking or Glow-worm.

1.15 Anti-theft Kits

Anti-theft kits are available for these appliances, contact Glow-worm for further information.

2000225229C

6

2 Flue and Ventilation

The flue must be installed in accordance with the rules in force in the countries of destination.

2.1 Terminal Position

The minimum acceptable siting dimensions for the terminal from obstructions, other terminals and ventilation openings are shown in diagram 2.1. For Ireland the minimum distances for flue terminal positioning must be those detailed in I.S.813 "Domestic Gas Installations".

The terminal must be exposed to the external air, the position allowing free passage of air across it at all times.

Car ports or similar extensions of a roof only, or a 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 car port consists of a roof and two or more walls, seek advice from the local gas company before installing the boiler.

If the terminal is fitted within 600mm below plastic guttering or painted soffit an aluminium shield 1500mm long should be fitted immediately beneath the guttering or eaves. If the terminal is fitted within 450mm below painted eaves or a painted gutter, an aluminium shield 750mm long should be fitted immediately beneath the guttering or eaves.

2.2 Flue Options

There are various flue systems to choose from, as follows:

Standard Top Outlet Flue Pack - Pt.No. 230483

Easyfit Top Outlet Flue Pack - Pt. No. 232057

Standard Rear Outlet Flue Pack - Pt. No. 230482

Extended Top Outlet Flue Pack - Pt. No. 230487

1 Metre Extension Kit - Pt. No. 230484

A flue system up to 3 metres in length can be made by connecting 1 metre flue extension kits together.

Optional Wall Liner Kit No. 900862

A Flue Bend Kit or Vertical Flue Kit up to 4 metres can be supplied, see Glow-worm's "Flue Options Guide" for configurations available.

45o Flue Bend Pack - Pt. No. 230485

90o Flue Bend Pack - Pt. No. 230486

In Line Flue Adapter Kit - Pt. No. 230488

Vertical Flue Kit No. 458115

		N
	A				C
P			B,C	B,C	M
Q			G	K
F	L	E		F
			A
				G
					11508
UNDER CAR PORT etc.

D

J

F

K

H,I

MINIMUM SITING DIMENSIONS FOR
FANNED FLUE TERMINALS POSITION	MM

HORIZONTAL FLUES

ADIRECTLY BELOW, ABOVE OR HORIZONTALLY TO AN OPENING, AIR BRICK,

OPENING WINDOW, AIR VENT, OR ANY
OTHER VENTILATION OPENING	300
B BELOW GUTTER, DRAIN/SOIL PIPE	25
C BELOW EAVES	25
D BELOW A BALCONY OR CAR PORT	25
E FROM VERTICAL DRAIN PIPES AND
SOIL PIPES	25

FFROM INTERNAL/EXTERNAL CORNERS OR TO A BOUNDARY ALONGSIDE THE

	TERMINAL	25
G ABOVE ADJACENT GROUND OR
	BALCONY LEVEL	300
H FROM SURFACE OR A BOUNDARY
	FACING THE TERMINAL	600
I	FACING TERMINALS	1200
J	FROM OPENING (DOOR/WINDOW)
	IN CAR PORT INTO DWELLING	1200
K	VERTICAL FROM A TERMINAL	1500
L	HORIZONTALLY FROM A TERMINAL	300
VERTICAL FLUES
M FROM ADJACENT WALL TO FLUE		300
N	FROM ANOTHER TERMINAL	600
P	FROM ADJACENT OPENING WINDOW	1000
Q	ABOVE ROOF LEVEL	300

Diagram 2.1

7	2000225229C

2 Flue and Ventilation

2.3 Terminal Guard

A terminal guard is required if persons could come into contact with the terminal or the terminal could be subject to damage.

If a terminal guard is required, it must be positioned to provide a minimum of 50mm clearance from any part of the terminal and be central over the terminal, see diagram 2.2.

A suitable guard, reference Type “K3”, can be obtained from:

Tower Flue Components Ltd.,

Morley Road,

Tonbridge,

Kent.

TN9 1RA

7056

Diagram 2.2

3 Water Systems

The installation of the boiler must comply with the requirements of the current issue of BS6798, in Ireland, refer also to the current edition of I.S.813 “Domestic Gas Installations”.

In GB it is necessary to comply with the Water Supply (Water Fittings) Regulations 1999 (for Scotland, the Water Byelaws 2000, Scotland).

To comply with the Water regulations your attention is drawn to: TheWaterRegulationsguidepublishedbytheWaterRegulations Advisory Service (WRAS) gives full details of the requirements.

In IE the requirements given in the current edition of I.S.813 “DomesticGasInstallations”andthecurrentBuildingRegulations must be followed.

3.1 Frost Protection

There is a built-in frost stat in this boiler. See Protection Against Freezing in Instructions for Use. Where other parts of the systemarevulnerablethisshouldalsobeconsideredasspecified in the current issue of BS5422.

3.2 Pump

The pump, with integral valves, should be fitted in the heating flow pipework from the boiler, it should be set to produce a temperature difference of 11oC (20oF), between the flow and return, with the boiler thermostat set at “MAX”, which is about 82oC (180oF).

The pressure loss of the boiler at 30.6 litre/minute giving 11oC temperature difference is 950mm head of water.

High resistance microbore systems may require a higher duty pump.

3.3 Bypass

A bypass is usually unnecessary on systems using a 3 port diverter valve since one port will remain in the open position at all times. This allows satisfactory operation of the pump overrun.

However if thermostatic radiator valves are fitted to all radiators or two port valves are used a bypass is required.

The bypass connection must be at least 2 metres away from the boiler.

The flow through the boiler must not be allowed to fall such that there is a temperature difference greater than 20oC between the flow and return.

Diagram 3.1

The cold feed must be 15mm minimum size.

It is important that the relative positions of the pump, cold feed and open vent are as shown in diagram 3.1.

Theunrestrictedopenventfromtheboilermustrisecontinuously to discharge over the feed and expansion cistern.

3.5 Domestic Hot Water System

General - All domestic hot water circuits, connections, fittings must be in accordance with the relevant standards and water supply regulations.

For GB: Guidance G17 to G24 and recommendation R17 to R24 of the Water Regulations Guide.

ForIE:ThecurrenteditionofI.S.813“DomesticGasInstallations”.

3.4 Water System

For an open vented system the boiler must be supplied from an unrestricted water supply taken from a feed and expansion cistern fitted at a maximum height of 27 metres above the boiler.

3.6 Cylinder

For all systems supplying domestic hot water the cylinder must be indirect. It is recommended that the cylinder be fitted with some form of temperature control.

2000225229C

8

3 Water Systems

3.7 Open Vented Fully Pumped Heating and

Domestic Hot Water

The connections for the system MUST be as shown in diagrams 3.1 and 3.2.

Plastic pipes should not be connected directly to the boiler. An intermediate metallic pipe of 1m in length should be fitted between the boiler and the plastic pipe system. Plastic pipes should be type S to BS7291.

3.8 Inhibitor

Attention is drawn to the current issue of BS5449 and BS7593 on the use of inhibitors in central heating systems.

When installing in an existing system take special care to drain the entire system, including radiators, then thoroughly cleaning out before installing the boiler whether or not adding an inhibitor.

3.9 Sealed Water Systems

Theinstallationshouldcomplywiththeappropriaterequirements of the current issue of BS4814, BS5449, BS6759, BS6798 and BS7074 Part 1 and 2.

3.10 Safety Valve

A safety valve must be fitted to a sealed water system.

It shall be preset, nonadjustable with a lift pressure of 3bar, incorporating seating of a resilient material, a test device and a connection for drain.

The drain from the safety valve must be routed clear of any electrical fittings and positioned so that any discharge can be seen.

3.11 Expansion Vessel - Sealed Systems only

A diaphragm type expansion vessel, conforming to the current issue of BS4814 (see also BS7074 Part 1 and 2) must be connected at a point close to the inlet side of the circulating pump, unless laid down differently by the manufacturer.

The expansion vessel volume depends upon the total water system volume and the initial system design pressure. For any system an accurate calculation of the vessel size is given in the current issue of BS7074 Part 1.

Example: For an initial system design pressure of 0.7bar the minimum total vessel volume required is 0.063xTotal System volume.

NOTE: A higher initial design pressure requires a larger volume expansion vessel.

Guidance on vessel sizing is also given in the current issue of BS5449 and BS7074 Part 1, for IE refer to the current edition of I.S.813 "Domestic Gas Installation".

The 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.

The water content of the boiler is given in Data Table 1.

3.12 Pressure Gauge - Sealed Systems only

A pressure gauge with a set pointer and covering at least the range of 0 to 4bar (0 to 60lb/in2) shall be permanently fitted to the system in a position where it can be seen when filling the system.

3.13 Domestic Hot Water Cylinder

SINGLE FEED INDIRECT CYLINDERS ARE NOT SUITABLE.

The domestic hot water cylinder must be of the indirect coil type. It must be suitable for working at a gauge pressure of 0.35bar above the safety valve setting.

3.14 Domestic Hot Water System - Unvented

Where a storage system will not have a vent to atmosphere the installation must comply with Building Regulations and local

WaterCompanyBye-laws,seealsothecurrentissueofBS6700.

If fitting into an existing system the local authority must also be advised.

3.15 Filling a Sealed Water System

Provision for filling the system at low level must be made. Theinstallationshouldcomplywiththeappropriaterequirements of the current issue of BS 5449.

3.16 Water Makeup

Provision must be made for replacing water lost from the system. A make up vessel mounted above the highest point of the system and connected through a non-return valve to the system on the return side of either the hot water cylinder or heating system.

6770	28mm	PUMPED RETURN	28mm	PUMPED FLOW
	PIPE
			PIPE
	22mm		22mm
			PIPE
	PIPE
				Diagram 3.2
9				2000225229C