Potterton Performa 28i User guide

Installation and
Servicing Instructions
Please leave these instructions with the user
Performa 28i
Gas Fired Wall Mounted Combination Boiler

2
Natural Gas
Potterton Performa 28i
G.C.No47 393 08
The boiler meets the requirements of Statutory
Instrument “ The Boiler (Efficiency) Regulations
1993 No3083” and is deemed to meet the
requirements of Directive 92/42/EEC on the energy
efficiency requirements for new hot water boilers
fired with liquid or gaseous fuels:-
Type test for purpose of Regulation 5 certified by:
Notified Body 0051.
Product/Production certified by:
Notified Body 0051.
For GB/IE only.

3
1.0 Introduction 4
2.0 General Layout 6
3.0 Appliance Operation 7
4.0 Technical Data 9
5.0 Dimensions and Fixings 10
6.0 System Details 11
7.0 Site Requirements 14
8.0 Installation 19
9.0 Commissioning the Boiler 24
10.0 Completion 26
11.0 Servicing the Boiler 27
12.0 Changing Components 29
13.0 Illustrated Wiring Diagram 38
14.0 Fault Finding 39
15.0 Short Parts List 46
Section Page
Contents

Potterton declare that no substances
harmful to health are contained in the
appliance or used during appliance
manufacture.
1.1 Description
1. The Potterton Performa 28i is a fully automatic
gas fired wall mounted combination boiler. It is
room sealed and fan assisted, and will serve
central heating and mains fed domestic hot water.
2.The unit incorporates a small storage cylinder
built into the boiler providing hot water the moment
the tap is turned on.
3. The boiler is set to give a maximum output of
29.4 kW in both modes.
4. It is designed for use on Natural Gas (G20) and
can be converted to use Propane.
5. The boiler is suitable for use only on fully
pumped sealed heating systems. Priority is given
to domestic hot water.
6. The boiler data badge gives details of the
model, serial number and Gas Council number
and is situated on the control box. It is visible when
the case front panel is removed (Fig. 1).
7. The boiler is intended to be installed in
residential / commercial / light industrial E.M.C.
environments on a governed meter supply only.
8. The boiler must be installed with one of the
purpose designed flues such as the standard
horizontal flue kit, part no. 247719.
9. All systems must be thoroughly flushed and
treated with inhibitor (see section 6.2).
1.2 Installation
1. The appliance is suitable for installation only in
G.B. and I.E. and should be installed in
accordance with the rules in force. For Ireland
install in accordance with I.S.813 “INSTALLATION OF
GAS APPLIANCES”. The installation must be carried
out by a CORGI Registered Installer or other
competent person and be in accordance with the
relevant requirements of GAS SAFETY (Installation
and Use) REGULATIONS, the BUILDING REGULATIONS
(Scotland) (Consolidation), the LOCAL BUILDING
REGULATIONS, the CURRENT I.E.E. WIRING
REGULATIONS and the bye laws of the LOCAL WATER
UNDERTAKING. Where no specific instructions are
given, reference should be made to the relevant
BRITISH STANDARD CODES OF PRACTICE.
1.0 Introduction
4
Data Badge
Fig. 1
Control Box
“Benchmark”Log Book
As part of the industry-wide “Benchmark”initiative all Potterton boilers now
include an Installation, Commissioning and Service Record Log Book.
Please read the Log Book carefully and complete all sections relevant to
the appliance and installation. These include sections on the type of
controls employed, flushing the system, burner operating pressure etc.
The details of the Log Book will be required in the event of any warranty
work. Also, there is a section to be completed at each subsequent regular
service visit. The Log Book must be left with the User.
Case Front Panel
NOTE: This appliance must be installed in
accordance with the manufacturer’s instructions
and the regulations in force.Read the instructions
fully before installing or using the appliance.

1.0 Introduction
5
1.3 Instant Domestic Hot Water
(Expansion Vessel & Pre-Heat Store)
1. The boiler expansion vessel incorporates a
small volume of stored primary hot water.
2. When the boiler has been off and there is then
a demand for domestic hot water the stored
primary hot water ensures that domestic hot water
is supplied instantly at temperature.
3. The stored hot water is part of the primary
circuit. This is not supplied as domestic hot water,
which is fresh mains water heated by a heat
exchanger within the boiler.
4. The stored primary hot water temperature is
maintained whilst the boiler is in operation. During
a period when there is no demand for heating or
hot water the temperature of the stored primary
hot water will eventually fall. The boiler will
operate occasionally in order to maintain the
temperature. This is indicated by the domestic hot
water mode neon flashing.
1.4 Optional Extras
1. Various flue extensions, bends, vertical flue
kits, control accessories etc. are available as
optional extras. These are detailed in a separate
publication.

2.0 General Layout
6
2.1 Layout
1. Air Pressure Switch
2. Expansion Vessel & Pre-Heat Store
3. Burner Manifold
4. Automatic Air Vent
5. DHW Plate Heat Exchanger
6. Circulation Pump
7. Drain Off Point
8. Pressure Relief Valve
9. Position for Optional Integral Timer
10. Central Heating System Pressure Gauge
11. PCB
12. Control Box
13. 3-Way Valve Assembly
14. Spark Generator
15. Flame Sensing Electrode
16. Spark Electrode
17. Burner
18. Primary Heat Exchanger
19. Fan Assembly
20. On/Off/Reset Selector Switch
21. Central Heating Temperature Control
22. Domestic Hot Water Pre-Heat Control
23. Flame Failure
24. Safety Thermostat
25. Fault on Fan or Flue
26. Fault on Pump or Low System Pressure
27. Fault on Hot Water Sensor
28. Fault on Central Heating Sensor
29. Power On
30. Domestic Hot Water Mode
31. Central Heating Mode
32. Burner On
When neons 23 to 28 are constantly illuminated,
they indicate the temperature of the central heating
water.
19
18
17
14
15
16
13
12 11
10 9
20 21 22 10 9
7
6
3
4
5
8
2
1
2
1
0
4
3
bar
30°40°50°60°70°80°
Reset
Preheat
Off
On
30°40°50°60°70°80°
23 24 25 26 27 28
29 30 31 32

3.0 Appliance Operation
7
NOTE: All delay timers mentioned in 3.1 and 3.2
are overridden by domestic hot water demand.
3.1 Central Heating Mode (Fig. 2)
1. With a demand for heating, the pump circulates
water through the primary circuit. At a pre-
determined flow rate the central heating flow
switch operates, initiating the ignition sequence.
2. The main burner ignites at low rate, then the
gas valve controls the gas rate to maintain the
heating temperature measured by the
temperature sensor.
3. When the flow temperature exceeds the setting
temperature, a 3 minute delay occurs before the
burner relights automatically (anti-cycling). The
pump continues to run during this period.
4. When the demand is satisfied the burner is
extinguished and the pump continues to run for a
period of 30 seconds (Pump Overrun).
5. If there is no other demand the pre-heat
function will operate if switched on (see Section
3.2).
3.2 Domestic Hot Water - Preheat Mode
(Fig. 3)
1. With the pre-heat function switched on (pre-
heat control fully clockwise), priority is given to the
replenishment of the pre-heat store. The DHW
mode neon ( ) will flash during this function.
2. The diverter valve remains in the DHW priority
position. This allows the pump to circulate hot
water to the store and back to the primary heat
exchanger via the bypass pipe.
3. The automatic ignition sequence commences
after approximately 25 seconds and the burner
will light.
4. When the store reaches the desired
temperature the burner is extinguished. The pump
continues to run for a period of 30 seconds.
5. Following a demand for domestic hot water or
the end of a central heating ON period, the pre-
heat function restarts.
27 19
16 15 14 13 12
10
9
11
8
17
21
23
20 22
19
28
26
56
7
2
34
1
25
24
18
1 Primary Heat Exchanger
2 Burner
3 Ignition Electrode
4 Flame Sensing Electrode
5 Gas Valve
6Pump
7 Automatic Air Vent
8 Plate Heat Exchanger
9 Flow Sensor with Filter
10 Pressure Relief Valve
11 Boiler Drain Point
12 Heating Return
13 Cold Water Inlet On/Off Valve and Filter
14 Gas Inlet
15 Domestic Hot Water Outlet
16 Heating Flow
17 Pressure Gauge
18 Hydraulic Pressure Sensor Microswitch
19 Automatic By-Pass
20 Hydraulic Pressure Sensor
21 Diverter Valve Assembly
22 Domestic Hot Water Flow Priority Assembly
23 Domestic Hot Water Flow Priority Microswitch
24 Safety Thermostat
25 Central Heating Temperature Sensor
26 Expansion Vessel & Pre-Heat Store
27 Domestic Hot Water Temperature Sensor
Key
Central Heating Mode
Fig. 2
27 19
16 15 14 13 12
10
9
11
8
17
21
23
20 22
19
28
26
56
7
2
34
1
25
24
18
Domestic Hot Water - Preheat Mode
Fig. 3

3.0 Appliance Operation
8
3.3 Domestic Hot Water Mode (Fig. 3A)
1. Priority is given to the domestic hot water
supply. A demand at a tap or shower will override
any central heating requirement.
2. The flow of water will operate the DHW flow
switch which requests the 3 way valve to change
position. This will allow the pump to circulate the
primary water through the DHW plate heat
exchanger and take the stored water to give
instant hot water.
3. The burner will light automatically and the
temperature of the domestic hot water is
controlled by the temperature sensor.
4. When the domestic hot water demand ceases
the burner will extinguish and the diverter valve
will remain in the domestic hot water mode,
unless there is a demand for central heating.
5. If there is no other demand the pre-heat
function will operate if switched on (see Section
3.2)
IMPORTANT: When the selector switch is in
the ‘0’(Off) position the electrical supply to the
boiler is isolated. The boiler will not operate
and the integral timer (if fitted) will require
resetting once the selector switch is set to
either Position (i) or Position (ii).
3.4 Frost Protection Mode
1. The frost protection mode is integral to the
appliance and functions only with the selector
switch (Section 2.1) in the domestic hot water and
central heating position. If the system temperature
falls below 5°C then the boiler will fire on its
minimum setting until a flow temperature of 30°C
is reached. Further protection can be incorporated
by using a system frost thermostat.
3.5 Pump Protection
1. With the selector switch (see Section 2.1) in
either the central heating or central heating and
domestic hot water position the pump will
automatically operate for 1 minute in every 24
hours to prevent sticking.
27 19
16 15 14 13 12
10
9
11
8
17
21
23
20 22
19
28
26
56
2
34
1
25
24
18
7
1 Primary Heat Exchanger
2 Burner
3 Ignition Electrode
4 Flame Sensing Electrode
5 Gas Valve
6Pump
7 Automatic Air Vent
8 Plate Heat Exchanger
9 Flow Sensor with Filter
10 Pressure Relief Valve
11 Boiler Drain Point
12 Heating Return
13 Cold Water Inlet On/Off Valve and Filter
14 Gas Inlet
15 Domestic Hot Water Outlet
16 Heating Flow
17 Pressure Gauge
18 Hydraulic Pressure Sensor Microswitch
19 Automatic By-Pass
20 Hydraulic Pressure Sensor
21 Diverter Valve Assembly
22 Domestic Hot Water Flow Priority Assembly
23 Domestic Hot Water Flow Priority Microswitch
24 Safety Thermostat
25 Central Heating Temperature Sensor
26 Expansion Vessel & Pre-Heat Store
27 Domestic Hot Water Temperature Sensor
Key
Fig. 3A
Domestic Hot Water Mode

4.0 Technical Data
9
4.2 Performa 28i
Flue Terminal Diameter 100mm
Dimensions Projection 95mm
Outercase Dimensions
Casing Height - 780mm
Overall Height Inc Flue
Elbow - 980mm
Casing Width - 450mm
Casing Depth - 345mm
Clearances
Both Sides 5 mm Min
Above Casing 200 mm Min
Below Casing 200 mm Min
Front 450 mm Min (For Servicing)
Front 5 mm Min (In Operation)
Weights kg
Packaged Boiler Carton 50.5
Packaged Flue Kit 3
Installation Lift Weight 44
Central Heating Primary Circuit
Pressures
bar
Safety Discharge 3
Max Operating 2.5
Min Operating 0.5
Recommend Operating 1-2
DHW Circuit bar
Pressures
Max Operating 8
Min Operating 0.2
Min Operating Pressure
at 12.7 l/min 0.96
Flow Rates l/min
DHW Flow Rate
@ 30o C Rise 13.9
DHW Flow Rate
@ 35o C Rise 12.0
Min Working
DHW Flow Rate 2.5
Pump - Grundfos UP 15-60
Available Head See graph below
Expansion Vessel - (For Central Heating
only. Integral with appliance)
bar
Min Pre-charge Pressure 0.5
litre
Max Capacity of
CH System 80
Primary Water Content
of Boiler (unpressurised) 3.2
Connections copper tails
Gas Supply - 22mm
Central Heating Flow - 22mm
Central Heating Return - 22mm
Cold Water Mains Inlet - 15mm
DHW Flow - 15mm
Pressure Relief Discharge - 15mm
Recommended System
Temperature Drop 11°C20°F
Temperatures
C.H. Flow Temp (adjustable)
35°C to 85°C max (± 5°C)
D.H.W. Flow Temp
35°C to 65°C max (± 5°C)
dependent upon flow rate
50°C Pre-heat OFF
65°C Pre-heat ON ± 5°C
dependent upon flow rate
Heat Input C/H & DHW (Gross)
Max Min
kW 32.6 11.9
Btu/h 111,250 40,610
Heat Output Max Min
kW 29.4 10.4
Btu/h 100,330 35,490
Electrical Supply 230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Power Consumption 190W
External Fuse Rating 3A
Internal Fuse Rating
Fuse 2A Fast Blow to BS 4265
Appliance Category CAT II 2H 3P
Max Gas Rate (Natural Gas - G20)
(After 10 Mins)
m3/h 3.45
ft3/h 122
Inlet Pressure (Natural Gas - G20)
mbar 20
in wg 8
Burner Injector (Natural Gas - G20)
15 x 1.28mm Diameter
Burner Pressure (Natural Gas - G20)
Max Rate Min Rate
mbar 12.5 ± 0.5 1.8 ± 0.2
in wg 5.0 ± 0.2 0.72 ± 0.2
Appliance Type C12 C32 NOxClass 3
Electrical Protection
IPX5D
This 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 0051.
SEDBUK Declaration
The seasonal efficiency (SEDBUK) is 78.2 %
0
200 400 600 800 1000 1200
0.5
1
1.5
2
2.5
3
3.5
4
Metre wg
l/h
Pump - Available Head
0
5
4.5
LPG Propane - G31
Burner Injector 15 x 0.77mm diameter
Burner Pressure
Propane mbar
in wg
Inlet Pressures
mbar
in wg
Max Rate
34.4 ±0.5
13.8 ±0.2
Min Rate
5.1 ±0.2
2 ±0.2
37
14.8

5.0 Dimensions and Fixings
10
Dimensions
A780mm
B345mm
C450mm
D107mm ØMin.
E200mm
F190mm
G143mm
360°Orientation
Tube Ø100mm
DC
B
A
E
G
F
Domestic Hot
Water Outlet
(15mm)
Cold Water
Inlet
(15mm)
Heating
Return
(22mm)
Heating
Flow
(22mm)
Pressure Relief
Valve
(15mm)
Gas
Inlet
(22mm)
65 mm 65 mm 65 mm 65 mm 65 mm
Tap Rail