Potterton envoy 30 Installation and maintenance instructions

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Envoy System 30, 40, 50, 60 & 80
Installation & Service Instructions
Envoy System
Wall Mounted, Fan Powered, Balanced Flue,
Gas Condensing System Boiler
EN0040A
THE GAS SAFETY (INSTALLATION AND USE) REGULATIONS 1994 (as amended).
‘‘ 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.’’
The polythene bags used for packaging are a potential hazard to babies and young children and
MUST BE DISPOSED OF IMMEDIATELY.
Installation must be in accordance with the Installation & Service Instructions and the rules in force.
LEAVE THESE INSTRUCTIONS WITH THE USER FOR USE ON FUTURE CALLS
For Use With Natural Gas
(G20) Only At 20mbar
For Use in GB & IE
IMPORTANT
PLEASE READ THIS BOOK
BEFORE INSTALLING,
OPERATING OR SERVICING
THIS BOILER.

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2Contents Publication No. 559787
Contents - Page 2
Technical Data........................................................... 3
1Installation Requirements........................................ 5
2Installation................................................................. 10
3Commissioning......................................................... 14
4Servicing & Replacement of Parts .......................... 17
Servicing:
Preparation of the Boiler............................................. 17
Removing Fan............................................................. 18
Removing Combustion Chamber & Flue Hood........... 18
Examination of Flueways & Cleaning ......................... 19
Re-assembly of Boiler................................................. 19
Replacement of Parts
1Fan.............................................................................. 20
2Hot Surface Igniter...................................................... 20
3Flame Sensor.............................................................. 20
4Insulation..................................................................... 20
5Burner......................................................................... 21
6Syphon.......................................................................21
7Flue Hood/Combustion Chamber Seals....................21
8Injector.......................................................................21
9Gas Valve Assembly..................................................21
10 Sight Glass ................................................................22
11 Water Temperature Sensor.......................................22
12 Dry Fire Temperature Sensor....................................22
13 Case Temperature Sensor ........................................22
14 Diverter Valve Head...................................................23
15 Boiler Control Board ..................................................23
16 Boiler Control Board Fuses........................................23
17 Water Components....................................................24
Pump........................................................................ 24
Diverter Valve...........................................................24
Water Pressure Gauge.............................................24
5Fault Finding ............................................................25
6Boiler Internal Wiring ..............................................28
7Boiler Wiring Layout................................................29
8Short List of Spares.................................................30
Introduction - Page 2
The Potterton Envoy System is a high efficiency lightweight,
automatically controlled wall hung gas fired condensing
boiler. The flue system is room sealed and fan powered.
There are five models available with outputs of 8.8kW
(30,000 Btu/hr), 11.7kW (40,000 Btu/hr), 14.6kW (50,000
Btu/hr), 17.6kW (60,000 Btu/hr) and 23.4kW (80,000 Btu/hr).
These boilers are designed to provide domestic hot water
and/or central heating and must be used on FULLY
PUMPED sealed systems only.
Concentric horizontal and vertical flues are available from 1
metre to 3 metres in steps of 0.5 metre using the following
options:-
Sales Code. Description.
EFLUEXT 500 - 0.5 metre Flue Extension
EFLUEXT - 1.0 metre Flue Extension
1EFLUEH - Std 1 metre Horizontal Flue
1EFLUEV - Std 1 metre Vertical Flue
Accessories
The following Potterton Myson controls are
recommended for use with your boiler:-
Electronic Programmer EP2002, EP3002 or EP6002
Cylinder Thermostat PTT2 or PTT100
Room Thermostat PRT2 or PRT100
Frost Thermostat PRT100FR
Motorised Zone Valve MSV222 or MSV228
Motorised Diverter Valve MSV322
Thermostatic Radiator Valve
Data sheets describing these products are available on
request.
Optional Extras
Sales Code. Description.
EWPLATE Terminal Wall Plate - where necessary
can be fitted to the outside face to
improve the appearance, after making
good around the terminal.
EGUARD Terminal Guard.
EFRFKIT Flat Roof Flashing Kit - for use with
Vertical Flue.
EPRFKIT Pitched Roof Flashing Kit - for use with
Vertical Flue.
ENVOYDIV Mid Position Diverter Valve Kit

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Publication No. 559787 Technical Data 3
Technical Data - Page 3
Boiler Details 30 40 50 60 80
Heat Input KW 10.1 13.43 16.87 20.2 26.86
Btu/hr 34,500 45,800 57,600 68,900 91,600
Heat Output,
NON-CONDENSING KW 8.79 11.72 14.65 17.58 23.45
Btu/hr 30,000 40,000 50,000 60,000 80,000
Heat Output,
CONDENSING KW 9.7 12.8 16.1 19.0 25.0
Btu/hr 33,100 43,700 55,000 64,800 85,400
Gas Rate M3/h 0.96 1.28 1.6 1.92 2.56
ft3/hr 34.0 45.2 56.7 68.0 90.4
Burner Pressure Mb 11.4 11.8 11.8 10.6 12.2
in/wg 4.6 4.7 4.7 4.24 4.9
Injector Size Mm 2.5 2.9 3.2 3.7 4.2
Classification I2H. C1. C3. IP20 Water Capacity 3.4 litre
Burner Furigas Pre-Mix Condense Discharge
Igniter Norton 401S Hot Surface Connection 21.5mm (¾"Plastic Compression)
Flame Detector Morgon Matroc Maximum Flow
Gas Control Valve SIT Nova Mix 1 - 8 Air Gas Ratio Temperature 82°C
Electrical Supply 230V ~ 50Hz Expansion Vessel 13.5 litre
Fuse Rating - External 3A (charge pressure 1.0 bar)
Packed Weight - Boiler 52kg Pressure Relief Valve 3 bar
Gas Supply Connections 15mm Compression Pump 30 - 60 Models CP53
Flow Connection 22mm Compression Pump 80 Model CP63
Return Connection 22mm Compression Flue Size 100mm Concentric
EN0030A
930
815
110
450
150
370 Main Casing
384 Including Door
Boiler Dimensions
Fig.1

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4Technical Data Publication No. 559787
Technical Data - Page 4
Fig.2

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1. Installation Requirements - Page 5
General Information
Prior to installation the boiler should be stored as
directed on the carton and in a dry place. Both the user
and manufacturer rely heavily on the installer, whose job
it is to install the boiler and connect it to a correctly
designed heating system. Acquaint yourself with the
British Standards concerning installation requirements. If
you need advice on any points, Potterton Myson’s
Service Operations will be pleased to help
(see back page).
Samples of the Envoy System Boilers have been
examined by Gastec, a Netherlands Notified Body. The
range is certified to comply with the essential
requirements of the Gas Appliance Directive
90/396/EEC, the Low Voltage Directive 72/23/EEC and
shows compliance with the Electro Magnetic
Compatibility Directive 89/336/EEC and are therefore
permitted to carry the CE mark.
It is important that no external devices e.g. flue
dampers, economisers etc, be directly connected to this
appliance unless covered by these Installation and
Service Instructions or otherwise recommended by
Potterton Myson Ltd. in writing. If in doubt please
enquire.
Any direct connection of a control device not
recommended by Potterton Myson could invalidate the
certificate and normal appliance warranty and could also
infringe the Gas Safety Regulations. Manufacturers
instructions must not be taken in any way as over-riding
statutory obligations.
Codes of Practice
The boiler must be installed in accordance with the Gas
Safety (Installation & Use) Regulations 1994 (as
amended), and the current issue of:-
I.E.E. Regulations.
Model Water Bye Laws.
Building Regulations.
Building Standards for Scotland.
Health and Safety Document No. 635. (The
Electricity at Work Regulations 1989).
Health and Safety Information for the
Installer and Service Engineer
Under the Consumer Protection Act 1987 and Section 6
of the Health and Safety at Work Act 1974, we are
required to provide information on substances
hazardous to health. Small quantities of adhesives and
sealants used in the product are cured and present no
known hazards. The following substances are also
present.
Insulation and Seals
Material - Ceramic Fibre. Alumino - Silicone Fibre.
Description - Boards, Ropes, Gaskets.
Known Hazards - Some people can suffer reddening
and itching of the skin. Fibre entry into the eye will cause
foreign body irritation. Irritation to respiratory tract.
Precautions - People with a history of skin complaints
may be particularly susceptible to irritation. High dust
levels are only likely to arise following harsh abrasion.
In general, normal handling and use will not present
discomfort, follow good hygiene practices, wash hands
before consuming food, drinking or using the toilet.
First Aid - Medical attention must be sought following
eye contact or prolonged reddening of the skin.
Electricity Supply
A 230 volts ~ 50Hz, single phase electricity supply fused
to 3A, must be provided in accordance with the latest
edition of the IEE Wiring Regulations and any other local
regulations that apply. The current rating of the wiring to
the boiler must exceed 3 A and have a cross sectional
area of at least 0.75mm in accordance with BS 6500,
Table 16.
The supply to the boiler and its associated equipment
should be controlled by an exclusive 3A fused double
pole switch (having at least 3mm contact separation in
both poles) so that complete isolation from the supply
can be achieved to enable servicing work to be carried
out in safety.
Gas Supply
A gas supply pressure of 20mbar is required at the inlet
of the appliance. Performance data is based on use of
reference gas G20. The meter and supply pipes must be
capable of delivering this quantity of gas in addition to
the demand from any other appliances in the house and
must be governed at the meter.
Condensate Drain
The condensate outlet on the boiler is designed to
accept 21.5mm (¾") plastic overflow pipe, which if
possible should discharge into the household drainage
system and have an internal termination. If this is not
practical, discharge into an outside gully or soak away is
acceptable. To avoid blockage of this pipe due to
freezing it should be routed internally where possible
and have sufficient fall over its entire length to dispose
of condensate quickly. See British Gas ‘Guidance Notes
for the Installation of Domestic Gas Condensing Boilers’.

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Installation Requirements - Page 6
Location of Boiler
These boilers are not suitable for external installation and
should not be fitted directly above a cooking appliance. The
boiler may be installed in any room, although particular
attention is drawn to the requirements of the current IEE Wiring
Regulations and in Scotland, the electrical provisions of the
Building Standards applicable in Scotland with the respect to
the installation of the appliance in a room containing a bath or
shower.
Where a room-sealed appliance is installed in a room
containing a bath or shower, any electrical switch or appliance
control, utilising mains electricity should be so situated that it
cannot be touched by a person using the bath or shower.
Where the installation of the boiler will be in an unusual
position, special procedures may be necessary and BS6798
and BS5546 give detailed guidance on this aspect.
It should be noted that due to the high efficiency of this boiler a
white plume of condensate will be emitted from the flue
terminal, therefore care should be taken when selecting the
terminal position.
Boiler Mounting Surface
The boiler must be mounted on a flat wall, which may be of
combustible material and must be sufficiently robust to take the
weight of the boiler. The requirements of the Local Authorities
and the Building Regulations must be adhered to.
Timber Framed Houses
If the boiler is to be installed in a timber framed building it
should be fitted in accordance with the British Gas publication-
Part 19 - Building and Kitchen Work. If in doubt advice must be
sought from the local region of British Gas or from Potterton
Myson.
Clearances around the Boiler and Tank
The following minimum clearances must be maintained after
installation for correct operation and servicing of the boiler and
tank.
Front: 15mm (610mm for servicing)
Sides: 5mm each side
Top: 140mm (from top of boiler case)
Bottom: 120mm
Ventilation
The room in which the boiler is installed does not require a
purpose provided air vent.
If the boiler is installed in a cupboard or compartment,
permanent air vents are required in the cupboard or
compartment, one at high level and one at low level, either
direct to the outside air or to a room. Both high level and low
level air vents must communicate with the same room or must
be on the same wall to outside air. Both the high level and low
level vent must each have a free area as stated below. The
free area of each vent may be halved if the ventilation is
provided directly from outside.
High and Low air vent areas:
Envoy System 30 103 cm²
Envoy System 40 135 cm²
Envoy System 50 170 cm²
Envoy System 60 206 cm²
Envoy System 80 277 cm²
If the boiler is installed in a cupboard or compartment with a
door, allow at least 15 mm clearance between the front of the
boiler and the door for air movement.
Flue Terminal and Ducting
The Standard Horizontal Flue system (Part No. 236346) is
suitable for installations up to 1030mm, measured from the
centre line of the boiler outlet to the outside face of the wall.
0.5 & 1 Metre Flue Extension kits (0.5m - Part No. 430092,
1m - Part No. 430085) are available to extend horizontal flues
to a maximum length of 2920 mm and vertical flues to a
maximum length of 3 metres. The siting positions for horizontal
flue terminals are shown in Fig. 3.
A Concentric Vertical Flue system is available (Part No.
236348) when used in conjunction with the 0.5 & 1 Metre Flue
Extension kits and is suitable for flue heights up to 3 metres to
terminate through a roof.
The siting of the flue terminal through a roof is shown in Fig. 3.
Only the flue systems shown here can be fitted to the Envoy
System boilers.
As with all condensing boilers, the flue will produce a plume of
visible condensation for much of the time that the boiler is
running.
Care must therefore be taken in the siting of the terminal so as
not to be a nuisance to adjacent property.
In particular, prolonged wetting of a facing wall should be
avoided, if necessary by use of an appropriate deflector.
If the terminal is fitted less than 2m (6.6 ft) above a balcony,
above ground or above a flat roof to which people have access
then a suitable terminal guard must be provided and fitted.
A protective guard is available from the Potterton Myson Sales
Office whose address and telephone number are shown on the
rear cover. The guard (Part No 236591) must be securely fitted
to the wall and centrally located over the flue terminal.
Where a flue terminal is installed less than one metre from a
plastic, or painted gutter, or 500mm from painted eaves, an
aluminium shield one metre long, should be fitted to the
underside of the gutter or painted surface. A suitable wall plate
should be fitted to the painted wall surface of a mobile home.

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Installation Requirements - Page 7
It is absolutely ESSENTIAL to ensure that products of
combustion discharging from the terminal cannot re-enter
the building, or any other adjacent building, through
ventilators, windows, doors, natural air infiltration, or forced
ventilation/air conditioning. If products of combustion are
found to be re-entering any building, the appliance MUST be
turned OFF IMMEDIATELY.
G
A
A
B,C
B,C
C
E
FGGG
G
K
LL
K
K
F F
EN0006A
Horizontal Flues
Vertical Flues
Flue Terminals
Facing Terminal
or Wall
A
P
R
Q
Q
S
N
N
N
H,I
Fig.3
Terminal position Minimum spacing
A - Directly below an openable window, air vent or any other ventilation opening 300 mm
B - Below gutters, soil pipes or drain pipes 75 mm
C - Below eaves (Horizontal Flue Only) 200 mm
* - Below balconies/Carport Roof Not Recommended
E - From vertical soil pipes or drain pipes 75 mm
F - From an internal or external corner 300 mm
G - Above adjacent ground or balcony level 300 mm
H - From a surface facing the terminal 2000 mm
I - From a terminal facing the terminal 2000 mm
* - From opening (Door/Window) in carport into dwelling Not Recommended
K - Vertically from a terminal on the same wall 1500 mm
L - Horizontally from a terminal on the same wall 300 mm
M - Adjacent to opening 300 mm
N - Above roof level (to base of terminal) 300 mm
P - From adjacent wall to flue 300 mm
Q - From internal corner to flue 400 mm
* - Below eaves or balcony (Vertical flue) Not Recommend
S - From facing terminal 2000

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Installation Requirements - Page 8
EN0004A
Filling
Point
By-pass
Balancing
Valve
Optional
Zone
Valves
Optional
3 Port
Valve
VentCylinderMake Up
Vessel
Fully Pumped
Sealed System
Alternative By-pass
Arrangement Using
The Bathroom
Radiator Fitted With
Two Lockshield Valves
Flow
(22mm)
Return
(22mm)
Boiler
Fig.4
The System
The Envoy System boiler has an aluminium alloy heat
exchanger, therefore all systems must be thoroughly
cleansed and the correct treatment added to the system
water.
The only system additives recommended by Potterton
Myson Ltd. are FERNOX-COPAL or GRACE
DEARBORN - SENTINEL X 100 and should be used in
accordance with the manufacturers instructions. This will
include use of the appropriate system cleanser.
The boiler must only be used on INDIRECT FULLY
PUMPED SEALED Systems.
To ensure sufficient pump head is available on the 80
model to overcome system resistance, a system
differential of 14°C should be allowed for when sizing
radiators.
Where the the D.H.W & C.H circuits are controlled by
two 2 port zone valves as illustrated or where all
radiators may be controlled by thermostatic radiator
valves a by-pass must be fitted.
Drain off taps should be fitted in the pipework close to
the boiler and at all low points of the system.
Note: Although the system can be emptied using the
drain off taps installed in the pipework around the
system, to empty the heat exchanger it is necessary to
remove the drain off cap positioned within the boiler
case.
Installation
The installation must comply with the requirements of
BS 6798: 1987 and BS 5449: Pt 1.
The British Gas publication "British Gas Specification for
Domestic Wet Central Heating Systems" should also be
consulted.
The following components are incorporated within the
appliance.
a) Circulating pump.
b) Diverter valve (Optional Extra).
c) Pressure Relief valve with a non-adjustable pre-set

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Installation Requirements - Page 9
lift pressure of 3 bar (45 psi).
d) Pressure gauge covering the range 0-4 bar (0-60
psi).
e) 13.5 litre expansion vessel with initial charge
pressure of 1.0 bar (14 psi).
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 under-floor spaces.
The expansion vessel on this appliance is suitable for
central heating systems up to 135 litres. For systems
greater than this, an additional expansion vessel will be
required.
Mains Water Feed: Central Heating
A connection must be incorporated into the central
heating system to facilitate filling. There must be no
direct connection to the mains water supply, even
through a non-return valve, without the approval of the
Local Water Authority.
Permissible Methods of Filling
(1) Direct Method (Fig. 5)
A detachable flexible hose is connected to a stop valve
fitted to an outlet on the service main. The other end of
the hose is connected to a second stop valve and a
double check valve. The double check valve is fitted to
an inlet connection on the central heating return pipe
under the appliance. The hose should be disconnected
after filling. Where the mains pressure is excessive a
pressure reducing valve could be used to make filling
easier. The following fittings shall form a permanent part
of the system and shall be fitted in the order stated.
a) A stop valve complying with the requirements of
BS 1010 Part 2, (the temporary hose from the
draw off tap shall be connected to this fitting).
b) Double check valve of an accepted type.
(2) Booster Pump Method
The system may be filled through a self contained unit
comprising a cistern, pressure booster pump and if
necessary, an automatic pressure-reducing valve or flow
restrictor.
The pressure booster pump must be capable of
pressurising the system to a minimum of 1.0 bar (14
p.s.i.) measured at the appliance.
The cistern should be supplied through a temporary
connection from a service pipe or cold water distributing
pipe. The unit may remain permanently connected to the
heating system to provide limited water make-up.
Provisions for make up water
Provision should be made for replacing water loss from
the system by re-pressurisation of the system. See
section on Methods of Filling.
Reference should be made to British Gas Publications
"Material and Installation Specifications for Domestic
Central Heating and Hot Water".
Note: The pre-charge pressure of the expansion vessel
is set at 1 bar, therefore, the cold fill pressure should be
1 bar.
Installation to an Existing Central Heating
System
The boilers are designed to operate on a sealed system
only, therefore if the existing system is of the open type
it will have to be modified to comply with BS 6798.
Before installing a new boiler to an existing system flush
out the old system with a recommended
descaling/flushing agent at least twice.
Also check pipework and renew any corroded pipework
or fittings. Valve glands must be re-packed or replaced
wherever necessary and any defective controls
replaced.
Pump
The variable speed circulating pump fitted within the
appliance should be capable of satisfying most system
requirements. Fig. 6 indicates the amount of pump head
available for the system. The boiler resistance is already
taken into account in this curve.

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Installation Requirements - Page 10
0
0
0.10.20.30.40.5
1.0
2.0
3.0
4.0
5.0
CP63
CP53
Litres / Sec
M / Head
EN0042A
To ensure sufficient pump head is available on 80 model to overcome system
resistance, a system differential of 14° should be allowed for.
Boiler Size Water Flow Rate System
Litres/sec gal. min Differential
30 0.19 2.50 10ºC
40 9.25 3.34 10ºC
50 0.32 4.17 10ºC
60 0.38 5.00 10ºC
80 0.40 5.27 14ºC
2. Installation
It is the law that gas appliances are installed and serviced by a competent person as stated in the Gas Safety (Installation &
Use) Regulations 1994.
Electrical test work should be carried out by a competent person in accordance with IEE wiring regulations.
The boiler and its associated equipment will arrive on site in 3 cartons. The contents will be as follows:-
Carton 1:- Boiler Pack Carton 2:- Flue Pack Carton 3:- Frame
Boiler Flue System Boiler Mounting Frame
Outer Casing Assembly Flue Installation Instructions Template
Accessory Pack Screw Pack
Literature Pack