Vaillant ECOmax VUW 236 EH User guide

ECOmax VUW 236 EH
G.C. No. 47 044 23
ECOmax VUW 286 EH
G.C. No. 47 044 24
Wall hung room sealed fan assisted
condensing combination boilers
INSTRUCTIONS FOR INSTALLATION AND SERVICING
HEATING, CONTROLS, HOT WATER

2
Page
1. Introduction 3
2. Boiler Specification 4
2.1 Technical Data 4
2.2 Dimensions 5
2.3 Boiler connections 5
2.4 Function diagram 6
3. General Requirements 7
3.1 Related documents 7
3.2 Boiler location 8
3.3 Gas supply 9
3.4 Flue system 9
3.5 Air suply 11
3.6 Electricity supply 11
3.7 Guide to system requirements 11
4. Boiler installation sequence 14
4.1 General 14
4.2 Boiler delivery 14
4.3 Preparation of boiler location 15
4.4 Pipework connections 17
4.5 Installing the flue system 18
4.6 Mounting the boiler 18
4.7 Connecting the flue assembly 20
4.8 Electrical installation 22
4.9 Controls 23
5. Commissioning 25
5.1 Preliminary electrical checks 25
5.2 Gas supply 25
5.3 Water supply 25
5.4 Filling the heating system 26
5.5 Initial system flush ('cold') 26
5.6 Filling condensate trap 27
5.7 Initial lighting 27
5.8 Gas inlet working pressure 28
5.9 Adjusting central heating
output (range rating) 28
5.10 Main burner pressure 29
5.11 Functional checks 30
5.12 Checking flame
supervision device 32
5.13 Final system flush ('hot') 33
5.14 Fitting case 33
5.15 Handing over to user 33
Page
6. Servicing 34
6.1 Initial inspection 35
6.2 Routine maintenance 35
6.3 Recommisioning the boiler 37
7. Parts replacement 38
7.1 Initial preparation 38
7.2 Fan 40
7.3 Air pressure sensor 41
7.4 Burner 41
7.5 Electrodes 42
7.6 Condensate sump 43
7.7 Condensate trap 44
7.8 Temperature sensors (NTCs) 44
7.9 Gas valve 44
7.10 Main Heat exchanger 45
7.11 CH expansion vessel 46
7.12 Main safety isolating
transformer 47
7.13 Ignition transformer 48
7.14 Pump 48
7.15 Automatic air release 49
7.16 Automatic bypass 49
7.17 Diverter valve 50
7.18 Pressure gauge 51
7.19 Water section 51
7.20 DHW microswitch 52
7.21 DHW heat exchanger 53
7.22 Circuit boards 53
8. Fault finding 57
8.1 Introduction 57
8.2 Logical fault finding procedure 58
8.3 Fault finding using fault mode 60
8.4 Fault diagnosis using
status mode 62
9. Electrical diagrams 65
9.1 Functional flow diagram 65
9.2 Wiring diagram 66
9.3 Schematic appliance
circuit diagram 67
10. Short parts list 68
11. Supplementary information
for ECOmax 70
THE GAS SAFETY (INSTALLATION AND
USE) REGULATIONS 1994:
`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 regula-
tions. Failure to install appliances
correctly could lead to prosecution.'
Leave these instructions with the user
when the installation is completed.

33
1. Introduction Note: This boiler must be installed and
serviced by a competent person in
accordance with the Gas Safety
(Installation and Use) Regulations
1994. In the U.K. `CORGI' Registered
Installers undertake the work to a safe
and satisfactory standard.
ECOmax is a fully automatic, wall
mounted, room sealed, condensing
(high efficiency) combination boiler
for central heating and domestic hot
water. Domestic hot water is supplied
directly from the boiler, and has priority
over the central heating. (This has the
advantage that no copper cylinder,
cold water tank, feed and expansion
tank and associ-ated pipework are
required).
The boiler has been designed for use
with sealed systems, and comes fully
tested and assembled with built-in
circulating pump, bypass, expansion
vessel and diverter valve.
The boiler, because it has a larger
heat exchanger, extracts more heat
from the flue gases. The conversion of
this otherwise wasted heat into usable
warmth means the boiler has a higher
efficiency. Because the flue gases are
reduced to such a low temperature,
the water vapour contained in them
can condense. To discharge this con-
densate a drain is provided on the
boiler, and this must be connected to
a drainage point on site.
The boiler features a comprehensive
diagnostic system, which gives de-
tailed information on the boiler status
when operating and performance of
key components to aid in commis-
sioning and fault finding.
ECOmax range consists of models
with outputs for domestic hot water
of 22.7 and 28.3 kW. The boiler is
easily sited on any internal wall
and can be installed with either a
horizontal or vertical RSF (Room
Sealed Fan assisted) flue. Flue
extensions and additional bends and
elbows are available for increased
siting flexibility. (The boiler is not
suitable for external installation).
If desired, an inhibitor may be used
in the system. Guidance on the use
of inhibitors is contained in these
instructions. (The boiler does not utilise
aluminium in the water system and
does not require a special inhibitor).
The boiler is designed to operate on
Natural Gas only.
The boiler contains a domestic hot
water heat exchanger. The temperatu-
re in the heat exchanger is limited by
the boiler control system and it is not
normally necessary to install a scale
reducer on the cold mains inlet to the
boiler. However, in exceptionally hard
water areas to prevent scale formation
in the property hot water system pipe-
work a scale reducer may be fitted.
The data badge is fitted on the com-
bustion chamber cover.
ECOmax boilers carry the „CE” Mark.
This demonstrates that the boilers fulfill
the essential requirements of the Gas
Appliance Directive (90/396/EEC)
and the Gas Appliance (Safety)
Regulations 1992.
The „CE” Mark also demonstrates
that the boilers comply with the
requirements of the Electromagnetic
Compatibility Drective
(89/336/EEC), the Low Voltage
Directive (73/23/EEC), the Boiler
Efficiency Directive (92/42/EEC)
and the Boiler (Efficiency) Regulations
1993.

44
ECOmax VUW 236 EH VUW 286 EH units
Countries of Destination GB, IE
Maximum CH heat input 19.5 (66,500) 24.2 (82,600) kW (Btu/h)
CH heat output range
80 °C flow/60 °C return 9.9-17.2 12.3-21.3 kW
(33,800-58,700) 42,000-72,700) (Btu/h)
50 °C flow/30 °C return 10.5-18.0 13.1-22.3 kW
(35,800-61,400) (44,700-76,100) (Btu/h)
Maximum DHW heat input 25.0 (85,300) 31.1 (106,100) kW (Btu/h)
Maximum DHW heat output 22.7 (77,500) 28.3 (96,600) kW (Btu/h)
DHW flow rate @ 35 °C rise 9.3 11.6 l/min
Mains water pressure required for max. flow rate 1.0 1.0 bar
Minimum water flow rate 2 2 l/min
Mains water pressure required for min flow rate 0.2 0.2 bar
Maximum inlet water pressure 10 10 bar
Inlet gas working pressure required (Natural Gas) 20 20 mbar
Gas supply (G20) Gross C.V. (s.t.) 37.8 37.8 MJ/m3
Gas burner pressure max (DHW) 3.0 3.0 mbar
Gas rate max (DHW) 2.38 2.96 m3/h
CH flow temperature range 35-90 35-90 °C
Minimum CH water flow (for 20 °C rise) 770 960 l/h
Pump pressure available 0.25 0.25 bar
12 l expansion vessel pre-charge pressure 0.8 0.8 bar
Maximum CH system pressure 3.0 3.0 bar
Connections
Heating flow / return 3/43/4in. BSP
Cold water inlet 15 15 mm
DHW outlet 15 15 mm
Gas inlet 15 15 mm
Condensate drain (internal diameter, min) 19 19 mm
Pressure relief discharge pipework (min) 15 15 mm
Weight 56 57 kg
Boiler water content 1.5 1.6 litres
Volume of condensate (max.) 0.5 0.6 l/h
Maximum flue gas temperature 70 70 °C
Electrical supply
Voltage 230/50 230/50 V~/Hz
Fuses internal/external 2/3 2/3 A
Power input 130 130 W
2. Boiler specification
2.1 Technical data

55
GW 398/0
fig. 1
2.3 Boiler connections
1 Connection support bracket
2 Service valve (flow of heating
system)
3 Domestic hot water connection
4 Compression Union (gas)
5 Gas service valve (supplied with
the boiler)
6 Cold water connection with
shut-off walve
7 Service valve (return of heating
system)
8 Discharge pipe
9 Pressure relief valve
10 Compression union (return of
heating system)
11 Compression union (flow of
heating system)
14 Boiler condensate drain
23 Frame of appliance (lower
connection)
GW 399/1
fig. 2
2.2 Dimensions
(All dimensions in mm)
1a Air/flue duct to the rear
1b Air/flue duct to the side
2 Appliance bracket
3 Heating system return 3/4” Rp
(3/4” B.S.P.)
4 Cold water connection (15 mm)
5 Gas connection (15 mm)
6 Hot water connection (15 mm)
11 Heating system flow 3/4” Rp
(3/4” B.S.P.)
12 Pre-assembled connection set
with service valves (flow and
return) pressure relief valve,
cold and hot water connection
13 Pressure relief valve 3/4” Rp
(3/4” B-S.P.)
14 Boiler condensate drain
(18 mm O. D.)
* with standard horizontal flue
accessory.
(max. = 6880 mm with extensions)

66
GW 512/1
fig. 3
2.4 Function diagram
1 Air duct
2 Flue gas duct
3 Fully modulating automatic gas
valve
4 Fully modulating fan
5 Fully modulating low NOx burner
6 Combustion chamber
7 Flame sensing electrode
8 High efficiency heat exchanger
9 Condensate trap
10 DHW heat exchanger
11 Boiler display
12 User control panel
13 DHW outlet
14 CH flow service valve
15 Gas service valve
16 Air pressure sensor
17 Ignition electrodes
18 Temperature sensors (NTCs)
19 Expansion vessel charging valve
20 Expansion vessel
21 Automatic bypass valve
22 Automatic air vent
23 Circulating pump
24 Diverter valve
25 Pressure gauge
26 Water section
27 Pressure relief valve
28 CH return service valve
29 Cold water shut off valve

7
3. General requirements 3.1 Related documents
The installation of the boiler must be in
accordance with the relevant require-
ments of Gas Safety (Installation and
Use) Regulations 1994, Health and
Safety Document No. 635 (The Elec-
tricity at Work Regulations 1989),
BS7671 (IEE Wiring Regulations) and
the bylaws of the local Water Under-
taking. It should be in accordance
with any relevant requirements of the
Local Authority, Building Regulations,
Building Standards (Scotland) Regu-
lations and the relevant recommen-
dations of the following British
Standards:-
BS 5440: Flues and ventilation of gas
fired boilers not exceeding 60 kW:
- Part 1: Flues
- Part 2: Ventilation
BS 5449: Specification for forced
circulation hot water for domestic
premises.
BS 5546: Specification for gas hot
water supplies for domestic premises.
BS 6700: Services supplying water
for domestic use within buildings and
their curtilages.
BS 6798: Specification for installation
of gas fired boilers not exceeding
60 kW input.
BS 6891: Specification for installation
of low pressure gas pipework up to
28 mm (R1) in domestic premises
(2nd family gas).
BS 7593: Treatment of water in dome-
stic hot water central heating systems.
BRITISH GAS PUBLICATION DM2:
Guide for Installation in Timber
Framed Housing
Important
The appliance must be installed and
serviced by a competent person as
stated in the Gas Safety (Installation
and Use) Regulations 1994

8
3.2 Boiler location
The location chosen for the boiler must
permit the provision of a satisfactory
flue termination. The location must
also provide adequate space for servi-
cing and air circulation around the
boiler. The boiler may be installed in
any room, although particular atten-
tion is drawn to the requirements of
the I.E.E. Regulations and, in Scot-
land, the electrical provisions of the
Building Regulations, in respect of the
installation of the boiler in a room
containing a bath or shower.
(Note: Where a room sealed boiler is
installed in a room containing a bath
or shower, any electrical switch or
boiler 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 location, special
procedures may be necessary and BS
5546 and BS 6798 give detailed gui-
dance on this aspect.
The boiler must be mounted on a flat,
vertical wall, which must be sufficient-
ly robust to take the weight of the boi-
ler. The boiler may be installed on a
combustible wall, subject to the
requirements of the Local Authorities
and Building Regulations.
A compartment used to enclose the
boiler must be designed and construc-
ted specifically for this purpose.
(An existing cupboard or compartment
may be used provided that it is modi-
fied for the purpose). Details of essen-
tial features of cupboard/compart-
ment design including airing cup-
board installations are given in
BS 6798.
If the boiler is to be fitted in a timber
framed building, it should be fitted in
accordance with British Gas Publica-
tion DM2 `Guide for Gas Installations
in Timber Framed Housing'.

9
GW 319/0
fig. 4
3.3 Gas supply
The gas supplier should ensure the
availability of an adequate supply of
gas.
A gas meter may only be connected
to the service pipe by the supplier of
gas or their contractor.
An existing meter should be checked
to ensure that it is capable of passing
the rate of gas supply required.
Installation pipes should be fitted in
accordance with BS 6891.
Pipework from the meter to the boiler
must be of an adequate size. Do not
use pipes of a smaller size than the
boiler gas connection (15mm).
The complete installation must be
tested for soundness and purged as
described in BS 6891.
3.4 Flue system
The standard horizontal flue system
(Accy No 300931) is suitable for
installations up to 1 metre measured
from the centre of the boiler flue outlet
to the outside face of the wall
(A, fig. 4). One metre flue extensions
(Accy No 300923) are available to
extend this length up to 6880 mm.
90 ° elbows (Accy No 300934) and
45 ° bends (Accy No 300949) are
also available to increase siting flexi-
bility.
A vertical flue system is also available
(Accy No 300945).
Refer to the flue installation instructions
for full details.

3.4.1 Flue Termination
1. The terminal must be positioned
such that the combustion products can
disperse freely at all times.
2. Flue gases from high efficiency con-
densing boilers are emitted at relative-
ly low temperatures, leading to a ten-
dency for a plume of water vapour to
be visible at or near the terminal.
More care should therefore be taken
when choosing the site for a terminal
of a condensing boiler. If possible
avoid placing the terminal below a
window, next to a door or close to
opposing walls. It is also recommen-
ded that the flue is not terminated
beneath a car port roof.
3. If the terminal is fitted less than 2m
above a balcony, above ground or
above a flat roof to which people
have access then a suitable guard
must be provided and fitted (available
from Tower Flue Components,
Tonbridge, TN9 1TB: reference
CGDK3BL).
Table 1:
Terminal position for fan-assisted flue.
(minimum distance - see fig. 5) mm
A- Directly below an openable
window or other opening
(e.g. air brick) 300
B- Below gutters, soil pipes
or drain pipes 751
C- Below eaves 2001
D- Below balconies 2001
E- From vertical drain pipes
and soil pipes 25
F- From internal or external
corners 3002
G-Above ground or balcony
level 300
H- From a surface facing a
terminal 600
I- From a terminal facing a
terminal 1200
K- Vertically from a terminal
on the same wall 1500
L- Horizontally from a
terminal on the same wall 300
M-Distance from adjacent
wall for Vertical Flue 500
10
2Dimension F: This clearance may be
reduced to 25mm without affecting
the performance of the boiler.
However, in order to ensure that the
condensate plume does not affect
adjacent surfaces a clearance of
300 mm is preferred.
fig. 5
GW 524/0
1 Dimensions B, C and D: These clear-
ances may be reduced to 25mm with-
out affecting the performance of the
boiler. In order to ensure that the con-
densate plume does not affect adja-
cent surfaces the terminal should be
extended as shown in fig. 6.
fig. 6
GW 445/0
Note: Vertical flues must not terminate
within 600 mm of an openable win-
dow, air vent or any other ventilation
opening.