Potterton envoy 30 Installation and maintenance instructions

Installation & Service Instructions
POTTERTON ENVOY 30, 40, 50, 60, & 80 FAN POWERED BALANCED FLUE
GAS FIRED CONDENSING BOILER
THE GAS SAFETY (INSTALLATION AND USE) REGULATIONS
“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.
LEAVE THESE INSTRUCTIONS WITH THE USER FOR USE ON FUTURE CALLS
For Use With Natural Gas
(G20) Only At 2Ombar For
Use in GB & IE
IMPORTANT
PLEASE READ THIS BOOK
BEFORE INSTALLING
OPERATING OR SERVICING
THIS APPLIANCE

2
SECTION
1. Technical Data
................................
................................
............................
Page 3
2. Installation Requirements....................................................................................5
3. Installation .........................................................................................................12
4. Commissioning..................................................................................................16
5. Servicing & Replacement of Parts.....................................................................23
6. Fault Finding......................................................................................................27
7. Electrical Diagrams............................................................................................28
8. Short Parts List..................................................................................................34
The Potterton ENVOY 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).
The boilers which are designed to provide domestic hot
water and/or central heating must be used on
INDIRECT FULLY PUMPED systems only, which may
be sealed or open vented.
The boilers can be supplied with either of the following
flue systems:-
One metre, 1.5 metre, 2 metre, 2.5 metre or 3 metre
horizontal and one metre, 1.5 metre, 2 metre, 2.5 metre
or 3 metre vertical.
ACCESSORIES
The following Potterton Myson controls are
recommended for use with your boiler:-
Electronic Programmer EP2002, EP3002 or EP6002
Cylinder Thermostat PTT2 or PTT1 00
Room Thermostat PRT2 or PRT100
Frost Thermostat PRT100FR
Motorised Zone Valve M5V222 or M5V228
Motorised Diverter Valve M5V322
Thermostatic Radiator Valve
Data sheets describing these products are available on
request.
OPTIONAL EXTRA
Terminal Wall Plate - where necessary can be fitted to the
outside wall face to improve the appearance, after making
good around the terminal. Part No. 236349. Terminal guard
Part No. 236591.
Flat roof flashing kit for use with vertical flue.
Part No. 430080.
Pitched roof flashing kit for use with vertical flue.
Part No. 430081.

3
TECHNICAL DATA – Page 3
Boiler Output 30 40 50 60 80
Heat Input kW
Btu/hr 10.1 34,500 13.43 45,800 16.87 57,600 20.2 68900 26.86 91,600
NONE CONDENSING
Heat Output kW
Btu/hr 8.79 30,000 11.72 40,000 14.65 50,000 17.58 60,000 23.45 80,000
CONDENSING
Heat Output kW
Btu/hr 9.7 33,100 12.8 43,700 16.1 55,000 19.0 64,800 25.0 85,400
Gas Rate M3/h
ft3/hr 0.96 34.0 1.28 45.2 1.6 56.7 1.92 68.0 2.56 90.4
Burner Pressure mb
in/wg 11.4 4.6 11.8 4.7 11.8 4.7 10.6 4.24 12.2 4.9
Injector Size mm 2.5 2.9 3.2 3.7 4.2
Classification
Burner
Igniter
Flame Detector
Gas Control Valve
Electrical Supply
Fuse Rating - External
Packed Weight
Water Capacity
Gas Supply Connections
Flow Connections
Return Connections
Condense Discharge Connection
Maximum Flow Temperature
Maximum Static Head
Minimum Static Head
Flue Size
12H. C1. C3. 1P20
Furigas Pre-mix
Norton 401S Hot Surface
Morgan Matroc
SIT Nova Mix 1-8 Air Gas Ratio
230V - 50Hz
3A
37.0 Kg
2.4 Litres
1/2” BSP Female Gas Cock
22mm Compression
22mm Compression
21.5mm (3/4”) Plastic Compression
82 Degree Centigrade
30.5M (100 Ft) Measured from the top of the casing
150mm (6”) Measured from the top of the casing
100mm Concentric
FIG.1 BOILER DIMENSIONS

4
TECHNICAL DATA – PAGE 4
FIG.2 GENERAL ARRANGEMENT

5
INSTALLATION REQUIREMENTS – Page 5
GENERAL INFORMATION
Both the user and the 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 Service Operations will be pleased to
help (see back page).
CODES OF PRACTICE
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).
BS.6891 Installation of low pressure pipes.
BS.6798 Installation of gas boilers of rated input
not exceeding 60kW.
BS.5449 Forced circulation hot water CH
systems. Including smallbore and
microbore domestic central heating
systems.
BS.5546 Installation of gas hot water supplies
for domestic purposes.
BS.5440:1 Flues (for gas appliances of rated input
not exceeding 60kW).
BS.5440:2 Air supply (for gas appliances of rated
input not exceeding 60kw).
BG.DM2 Guide for gas installation in timber
framed buildings.
Note: Samples of Envoy boiler have been examined by
the Netherlands Notified Body, Gastec and the range is
certified to comply with the essential requirements of
the GAD and is permitted to carry the CE Mark.
It is important that no external control 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 in writing. If in doubt please enquire.
Any direct connection of a control device not
recommended by Potterton could invalidate the
certificate and the 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.
ELECTRICITY SUPPLY
A 230 volts - 50Hz, single phase electricity supply fused to 3
amperes, must be provided in accordance with the latest
edition of the lEE Wiring Regulations and any other local
regulations that apply. The current rating of the wiring to the
boiler must exceed 3 amperes and have a cross sectional
area of at least 0.75mm2 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 20 mbar is required at the inlet to
the appliance. Performance data is based on use of
reference gas G20.
CONDENSATE DRAIN
The condensate outlet on the boiler is designed to accept
21.5mm (314 in) 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’.
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 lEE
Wiring Regulations and in Scotland, the electrical provisions
of the Building Standards applicable in Scotland with
respect to the installation of the appliance in a room
containing a bath or shower.

6
INSTALLATION REQUIREMENTS – Page 6
Where a room-sealed appliance is installed in a room TABLE 1
containing a bath or shower, any electrical switch or AIR VENT AREAS
appliance control, utilising mains electricity should be in2cm2
so situated that it cannot be touched by a person 30 16 103
using the bath or shower. 40 21 135
50 26 170
Where the installation of the boiler will be in an 60 32 206
unusual location, special procedures may be 80 43 277
necessary and BS.6798 gives 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.
Ensure that the gas supply pipe and meter are large
enough for the appliance and any others that may be
run off the same meter. Reference should be made to
BS.6891.
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.
IMPORTANT NOTICE:–TIMBER FRAMED HOUSES
If the appliance is to be fitted in a timber framed
building, it should be fitted in accordance with British
Gas Publication ‘Operational Procedures for Customer
Service’ Part 19. If in any doubt, advice should be
sought from the local region of British Gas.
CLEARANCES AROUND THE BOILER
The following minimum clearances must be maintained
after installation, for correct operation and servicing of
the boiler:
610mm (2ft) at the front of the boiler
5mm (0.2 in) each side of the boiler
140mm (5.5 in) at the top (measured from the top
of the boiler case)
100mm (4 in) at the bottom of the boiler
VENTILATION
If the boiler is to be installed in a confined space such
as a cupboard, the space will need ventilating.
Openings must be provided at the top and bottom of the
cupboard each of which should have a free area as
shown in TABLE 1. Further details for installation of a
boiler within a compartment are given in BS.6798.
If the openings draw air from outside the building the free
areas may be halved. Refer to BS.5440 Part 2 for further
guidance.
FLUE TERMINAL AND DUCTING (Fig. 3a, b & c)
The standard horizontal flue system (Potterton 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.
One metre flue extension kits (Part No. 430085)
are available to extend horizontal flues to a maximum
length of 2920mm. The siting positions for horizontal flue
terminals are shown in Figs. 3a, b & c.
A concentric vertical flue system is available (Part No.
236348) which when used in conjunction with one metre
flue extension kits (Part No. 430085) 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. 3c.
Only the above flue systems should be used with Envoy
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 a horizontal flue is sited less than 2m above a balcony,
above ground, or above a flat roof to which people have
access, a suitable terminal guard must be fitted. This
serves two purposes, to protect the terminal against
damage or interference and to protect passers-by. A
terminal guard is available (Part No. 236591).

7
INSTALLATION REQUIREMENTS – Page 7
Note: 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.
IMPORTANT: 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.
FIG. 3 FLUE TERMINAL POSITIONS
Mm. Distance mm
ADIRECTLY BELOW AN OPENABLE WINDOW, AIR VENT, OR ANY
OTHER VENTILATION OPENING 300
BBELOW GUTTER, DRAIN/SOIL PIPE 75
CBELOW EAVES (HORIZONTAL FLUE ONLY) 200
*BELOW A BALCONY/CARPORT ROOF NOT RECOMMENDED
EFROM VERTICAL DRAIN PIPES AND SOIL PIPES 75
FFROM INTERNAL OR EXTERNAL CORNERS 300
GABOVE ADJACENT GROUND OR BALCONY LEVEL 300
HFROM A SURFACE FACING THE TERMINAL 600
IFACING TERMINALS 1200
*FROM OPENING (DOOR/WINDOW) IN CARPORT INTO DWELLING NOT RECOMMENDED
KVERTICALLY FROM A TERMINAL ON THE SAME WALL 1,500
LHORIZONALLY FROM A TERMINAL ON THE SAME WALL 300
MADJACENT TO OPENING 300
NABOVE ROOF LEVEL (TO BASE OF TERMINAL) 300
PFROM ADJACENT WALL TO FLUE 300
QFROM INTERNAL CORNER TO FLUE 400
*BELOW EAVES OR BALCONY (VERTICAL FLUE) NOT RECOMMENDED
SFROM FACING TERMINAL 2000

8
THE SYSTEM – Page 8
The Envoy boiler has an aluminium alloy heat
exchanger therefore all systems need to be thoroughly
cleansed and the correct treatment added to the system
water.
The only system additives recommended by Potterton
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 be used on INDIRECT FULLY
PUMPED systems only, which may be sealed or open
vented.
The system should be designed so that the maximum
static head does not exceed 30.5m (100ft) and a
minimum of 150mm (6in). See FIG. 4.
On all systems the pump live should be wired to the
boiler terminal block, it will then be controlled by the
pump over-run timer. This will ensure that the pump will
continue to run after boiler shut down if the water
temperature is high, thus preventing nuisance operation
of the overheat control.
It is important that where electrically operated zone
valves are used the boiler is wired so it does not cycle
when the zone valves are closed. Also, systems fitted
with controls that close both hot water and central
heating circuits while the boiler is still hot, must be fitted
with a by-pass circuit to dissipate residual heat from
within the boiler.
If a three port diverter valve is used as shown in FIGS.
4 & 5 a by-pass is not necessary since one circuit is
always open.
Where a pair of two port valves are used, a by-pass is
necessary. The total length of the by-pass circuit taken
from the boiler connections should be greater than 4
metres of 22mm pipe. It should be fitted with a
lockshield valve and be adjusted to maintain a minimum
flow through the boiler of 4.5 litres/mm (1 gal/mm)
see FIGS. 4 & 5.
Systems fitted with controls which allow the boiler to
operate when both the hot water and central heating
circuits are closed i.e. mechanically operated
thermostatic control valves, must be fitted with a by-
pass circuit capable of:-
1. Dissipating a minimum of 1kW (3400 Btu/h).
2. Maintaining a minimum water flow through the boiler
of 9 litres/mm (2 gal/mm).
A suggested method of meeting these requirements by
using a bathroom radiator fitted with two lockshield valves
is shown in FIGS. 4 & 5.
Drain off taps should be fitted in the pipework close to the
boiler and in the 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 boiler it is necessary to remove the drain off
cap positioned within the boiler case. See FIG. 2.
SEALED SYSTEMS
Installation
The installation must comply with the requirements of
BS.6798 1987 and BS.5449 Part 1. The B.G. publication
“British Gas Specification for Domestic Wet Central
Heating Systems” should also be consulted.
SAFETY VALVE
A non-adjustable spring-loaded safety valve, preset to
operate at 3 bar (451bf/in2) shall be used. It must comply
with BS.6759 Part 1 and include a manual testing device.
It shall be positioned in the flow pipe either horizontally or
vertically upwards and close to the boiler. No shut-off
valves are to be placed between the boiler and the safety
valve. The valve should be installed into a discharge pipe
which permits the safety discharge of steam and hot
water such that no hazard to persons or damage to
electrical components is caused.
PRESSURE GAUGE
A pressure gauge incorporating a fill pressure indicator,
covering the range 0-4 bar (60Ibf/in2) shall be fitted to the
system. It should be connected to the system, preferably
at the same point as the expansion vessel. Its location
should be visible from the filling point.

9
THE SYSTEM – Page 9
EXPANSION VESSEL
A diaphragm type expansion vessel to BS.4814 Part 1
shall be fitted close to the inlet side of the pump. The
connecting pipework should not be less than 15mm
(1/2in nominal). Pipework connecting the expansion
vessel should not incorporate valves of any sort.
Methods of supporting the vessel are supplied by the
manufacturer. The nitrogen or air charge pressure of
the expansion vessel shall not be less than the
hydrostatic head (height of the top point of the system
above the expansion vessel). To size the expansion
vessel it is first necessary to calculate the volume of
water in the system in litres. The following volumes may
be used as a conservative guide to calculating the
system volume.
CYLINDER
The hot water cylinder must be an indirect coil type or a
direct cylinder fitted with an emersion calorifier suitable for
operating at a gauge pressure of 0.3 bar (Slbf/in2) in
excess of safety valve setting. Single feed indirect
cylinders are not suitable for sealed systems.
METHOD OF MAKE-UP
Provision shall be made for replacing water loss from the
system either:-
i) from a make-up vessel or tank mounted in a position
higher than the top point of the system, and
connected through a non-return valve to the system
Boiler Heat Exchanger 2.4 litres on the return side of hot water cylinder or the return
Small Bore Pipework 1 litre per kW of system side of all heat emitters.
output or
Micro Bore Pipework 7 litres
Steel Panel Radiators 8 litres per kW of system -
output ii) where access to make-up vessel would be difficult by using the mains top up method or a
Low Water Capacity - 2 litres per kW of system - remote automatic pressurisation and make-up unit
Radiators output as illustrated in FIG. 5, Methods 1 and 2.
Hot Water Cylinder 2 litres
If the system is extended, the expansion vessel volume
may have to be increased unless previous provision
has been made for the extension. Where a vessel of the
calculated size is not available, the next available larger
size should be used.
The boiler flow temperature is controlled at
approximately 820C MAX.
The vessel size can now be determined from the
following table where V=System volume in litres.
MAINS CONNECTION
There shall be no connection to the mains water supply or
to the water storage tank which supplies domestic water
even through a non-return valve, without the approval of
the local Water Authority.
FILLING POINT
The system shall be fitted with a low filling point at low
level which incorporates a stop valve to BS.1010 and a
double check valve (approved by the National Water
Council) to be fitted in this order from the system mains,
refer to FIG. 5, Method 1.
Vessel Charge Pressure (Bar) 0.5 1.0
Initial System Pressure (Bar) 1.0 1.0
Expansion Vessel Volume Litres V x 0.11 V x 0.087

10
THE SYSTEM – Page 10
FIG. 4: OPEN VENTED FULLY PUMPED SYSTEM FITTED WITH A COMBINED FEED AND VENT
FIG. 5: FULLY PUMPED SEALED SYSTEM.