Page 1
chaffoteaux ltd.
CORVEC 28 OF
BF GC No 41 980.28
CORVEC 28 BF
OF GC No 41 980.27
installation
servicing requirements
Leave these instructions at or near the service Gas Meter.
Page 2
contents
Page 3
: TECHNICAL DATA
The CORVEC 28 is a wall mounted, low water content
boiler available in both balanced flue and ouen flue versions. The boiler is rated at 4 kW (13660 Bt&h) 6.5 kW
(22350 Btu/h) or 8.2 kW (28000 btu/h).
Pages 4, 5, 6, 7, 8,
9,10,11 and 12
: INSTALLATION
The boiler is designed for use with Natural Gas only,
unless otherwise stated.
Pages 13 and 14
Page3 15
Pages 17
: SERVICING
REQUIREMENTS
: FAULT FINDING CHART
: SHORT LIST
A pump must be installed in the water circulation system
irrespective of whether the system is of the open or sealed
type.
The CORVEC 28 balanced flue version is supplied in two
cartons, one containing the boiler and the other containing the balanced flue set. The CORVEC 28 open flue
version is supplied in one carton.
The guarantee on this is voidable if it is not installed in accordance with the recommendations made herein or in a manner
approved by the manufacturer.
CORVEC 28 BF
water
CORVEC 28 OF
A
200
B 80
C 269
D 100
E 960
F 55
G 600
H 65
I 218
. .
dnnemmminm.m
7
Page 3
technical data
HEAT OUTPUT
HEAT INPUT SETHNG PRESSURE RESTRImOR SIZE GAS RATE
kW
Btulh kW Btu/h mbar in w.g.
mm dia f&h m3/h
OF MODEL
8.2
28,000 10.66 36,400 9.2 3.7
2.8 34.9 0.98
6.5
22,350 8.60 29,380 6.2 2.5
2.2 28.1 0.79
4.0
13,660 5.33 18,200 2.7 1.0
1.7 17.4 0.49
BF MODEL
8.2
28,000 10.4 35,480 9.2 3.7
2.8 34 0.94
6.5
22,350 8.4 28,660 6.2 2.5
2.2 28 0.77
4.0
13,660 5.2 17,740 2.7 1.0
1.7 17 0.47
N.B. -
These boilers are supplied with the 8.kW (28000 Btu/h) output restrictor fitted. Other restrictors are in an accompa-
nying carton. See 6.5
CLEARANCE FOR INSTALLATION AND SERVICING
,alanced flue version :
Sides ................................
25 mm (1 ins)
Top ................................
76 mm (3 ins)
Bottom ............................
127 mm (5 ins)
Front .............
.:
............ 600 mm (23.6 ins)
Open flue version :
Sides ................................
76 mm (3 ins)
Top
................................ 76 mm (3 ins)
Bottom..
.............................. 127(5ins)
Front ...........................
600 mm (23.6 ins)
FLUE CONNECTION
Balanced flue version :
Open
flue version :
Flue set requires a hole in the wall 125 mm high x 240
Requires a nominal 100 mm (4 in) flue pipe. No split col-
mm wide (6.9 ins x 9.4 ins)
lar is required. Draught diverter is integral.
GAS CONNECTION : R l/2 in. (112 in. BSP taper male)
WATER CONNECTIONS
: Flow : R 314. 314 BSP on left hand side of boiler viewed from front.
Return : R 314. 3/4 BSP.
‘he open flue version has male threads (R 3/4), the balanced flue, female threads (Rc 3/4).
MINIMUM WATER FLOW RATE : 450 L/hr. 1.65 gpm.
MINIMUM STATIC HEAD AT BOILER : 0.15 Metre (6 ins) See section 5.
MAXIMUM STATIC HEAD AT BOILER : 30 Metres (98 ft).
ELECTRICAL CONNECTIONS : None on the boilers (all control via pump etc.)
DIMENSIONS
Balanced flue version :
Open flue version :
600 mm high x 269 mm wide x 218 mm deep
600 mm high x 269 mm wide x 218 mm deep
(23.6 ins x 10.6 ins x 8.6 ins)
(23.6 ins x 10.6 ins x 8.6 ins)
WEIGHT : 13.6 kg (30 lbs)
WATER CAPACITY
: 0.182 litres (0.04 gals)
A 6 blade Chaffoteaux burner is used fitted with 1.18 mm dia injectors. The non-adjustable permanent pilot is manually
ignited by a piezo ignitor. The flow temperature is controlled by a non-adjustable thermostat at a nominal 82” C (ISO F).
3
Page 4
installation
&INSTALLATION
.
General
REQUIREMENTS
The installation of the boiler must be in accordance with
the Gas Safety Regulations, Building Regulations, I.E.E.
Regulations and the Byelaws of the local Water Undertaking. It should be in accordance also with BS Codes of
Practice and the British Gas Publication. Material and
Installation Specification for Domestic Central Heating
and Hot Water, and any relevant requirements of the
local Gas Region and Local Authority.
3.2.
Location
The position chosen for the boiler should permit the pro-
vision of a satisfactory flue termination. The position
should also provide adequate space for servicing and air
circulation around the boiler.
Where installation will be in an unusual position, special
procedures may be necessary, and BS 5376 : 2 gives
detailed guidance on this aspect.
A cupboard or compartment used to enclose the boiler
must be designed and constructed specifically for this
purpose. An existing cupboard or compartment may be
used provided that it is modified for the purpose.
Details of essential features of cupboard/compartment
design are given in BS 5376 : 2.
33. Gas Supply
The gas installation should be in accordance with CP
331 : 3.
The meter to be used must be of adequate capacity to
meet the total gas load, i.e. boiler plus other gas applian-
CeS.
Ensure that the pipework from the meter to the boiler is
of adequate size. Do not use pipes of a smaller size than
the boiler gas connection.
The compiete installation must be tested for soundness as
described in the above Code.
3.4. Fiueing
Detailed recommendations for flueing are given in
BS5440: 1.
The following notes are for general guidance only.
3.4.1.
Balanced Flue Version
The boiler must be installed so that the flue terminal discharges directly into the external air.
Termination should be on a clear expanse of wall; the
terminal being preferably not less than 600 mm (2 ft)
from a corner, recess or projection.
(a)
(b)
(cl
Within 300 mm (1 ft), measured vertically, from
the bottom of an openable window, air vent or
any other ventilation opening.
Less than 300 mm (1 ft) from ground level.
Less than 600 mm (2 ft) from any surface facing
the terminal.
(4
Immediately beneath eaves or a balcony.
Where the terminal is less than 2 m (6.6 ft) above the
level of any ground, balcony, flat roof or place to which
people have access, the terminal must be protected by a
guard of suitable material.
Where a terminal guard has not been supplied
(optional
extra) with the boiler, one may be obtained from Chaffo-
teaux Limited.
The air inlet/products outlet duct and the terminal
should be no closer than 50 mm (2 in) to combustible
material. Detailed recommendations on protection of
combustible material are given in BS 5440 : 1.
3.4.2.
Open Flue Version
The boiler should be sited such that the maximum possible length of the flue system.can be contained within the
building and that the route of the flue rises continuously
to the terminal and is as direct as praticable.
Where 600 mm (2 ft) of flue pipe should rise vert ically
from the draught diverter connection before the use of
any bends or elbows.
Horizontal or shallow angle runs, right angled bends and
mitred elbows should be avoided.
Where an existing brick chimney is to be used, it should
be swept thoroughly before connection of the new boiler,
and the chimney should be lined.
An approved British Gas terminal must be fitted and the
terminal sited at the adjacent roof edge, and where possible above the ridge line. The flue must not be terminated
at or adjacent to a wall face.
3.5.
Air Supply
Detailed recommendations for air supply are given in BS
5440 : 2.
The following notes are intended to give general guidance.
3.5.1.
Balanced Flue Version
The room in which a balanced flued boiler is installed
does not require a purpose provided air vent.
Where a balanced flued boiler is installed in a cupboard
or compartment, air vents are required (for cooling purposes) in the cupboard or compartment at high and low
level. These air vents may communicate with a room or
direct to outside air.
The minimum effective area requirement of
cupboard/compartment air vents are as follows.
Position of
air vents
High Level
Low Level
Air from
room
90
cmz
14
it?
90
cm1
14
in’
Air direct
from outside
45
cm’
7
in2
45
cm’
7 in3
Note - Both air vents must communicate with the same
room, or must be on the same.‘waii to outside air.
4
Page 5
installation
3.5.2. Open Flue Version
3.5.2.1. Room or Internal Space Air Supply
Where the boiler is to be installed in a room or internal
space, the boiler requires the room or internal space containing it to have a permanent air vent. This vent must be
either direct to outside air or to an adjacent room or
internal space which must itself have a permanent air
vent of at least the saae size direct to outside air.
The minimum effective area of the permanent air vent (s)
is related to the maximum rated input of the boiler and
should be 15 cm’ (2 in’).
3.5.2.2. Cupboard or Compartment Air Supply
Where the boiler is to be installed in a cupboard or compartment permanent air vents are required (for combustion, flue dilution and cooling purposes) in the cupboard
or compartment at high and low level. These air vents
must either communicate with a room or internal space
or be direct to outside air.
The minimum effective areas of the permanent air vents
required in the cupboard or compartment are specified
below and are related to the maximum rated heat input
of the boiler.
POSITION
AIR VENT AREAS
OF
Air from room
Air direct from
AIR VENTS
or internal space
outside
High
90 cm2
45
cm2
Level
14
in2
7 in2
Low
180 cm’
90 cm2
Level
28
in2
14 in*
Note : Both air vents must communicate with the same
room or internal space or must both be on the same wall
to outside air.
Where cupboard or compartment air vents communicate
with a room or internal space, the room or internal space
must itself a permanent air vent (s) as specified in
3.5.2.1.
3.5.3.
Effect of an Extract Fan
If there is any type of extract fan fitted in the premises,
there is a possibility that if adequate air inlet area from
outside is not provided, spillage of the products from the
boiler flue could occur when the extract fan is in operation. Where such installations occur, a spillage test as
detailed in BS 5440 : 1 must be carried out and any necessary action taken.
3.6.
Water Circulation Systems
Open or sealed type central heating systems should be in
accordance with the relevant recommendations given in
BS 5376 : 2. BS 5449 : 1 (for smallbore or microbore
systems) and the British Gas publication entitled (( Material and installation Specifications for Domestic Central
Heating and Hot Water 1).
Hot water systems should be in accordance with the relevant recommendations given in CP 342 : 1 and the above
mentioned British Gas publication and BS 5546.
3.7.
Electrical Supply
The CORVEC 28 boiler has no electrical connections,
but all wiring external to the boiler must be in accordance
with the I.E.E. Regulations.
For external wiring instructions, see 4.6. Electrical Connections.
4) INSTALLATION OF BOILER
4.1.
General
A vertical flat area is required for the boiler as follows.
Balanced Flue Version - 319 mm wide x 803 mm high
(12.6 ins x 31.6 ins).
Open Flue Version
(16.6 ins x 31.6 ins).
- 421 mm wide x 802 mm high
Above dimensions include the necessary clearances
around the boilers for case removal and for air movement.
4.2.
Fheing
4.2-l.
Balanced Flue Version
The standard flue set supplied with the boiler is suitable
for walls having a thickness of 75 mm to 355 mm (3 ins
14 ins). (Flue sets for walls of thickness up to 610 mm (24
in) are available to special order).
Using the boiler as a template determine the position for
the flue duct. The following procedure should now be
followed.
(a)
Prepare the Wall
Cut a hole in the wall which measures 20 mm
high x 240 mm wide (4 l/2 x 9 l/2 in). If the
hole is cut accurately, there is no need to line the
hole, since the wall liner make a satisfactory
seal.
(b)
Prepare the Parts
Cut the wall liner to the same length as the wall
thickness. Cut the flue duct to the same length,
plus 80 mm (3.25 ins).
(cl
Fit the wall Liner (fig. 1) (see page 6).
Position the wall liner in place. Ensure that the
liner is square and horizontal with the seam
uppermost and that the flange is flush with the
inside face of the wall. With the liner fixed in
place, make good the external and internal wall
surfaces around the liner with cement.
5
Page 6
installation
4.2.2.
Open Flue Version
The CORVEC 28 open flue version has a draught diverter outlet suitable for a nominal 100 mm (4 in flue pipe).
The flue should be installed in accordance with the requirements of BS 5440 : 1.
4.3.
FITTING THE BOILER
4.3.1.
Blanced Flue Version
Pull off the gas control knob. remove the screw below
the gas control knob and the two screws top and bottom.
Remove the front cover by pulling forwards.
Remove the Flue Bend from the top of the heat exchanger (two screws).
Fix the top bracket to the rear boiler case using the
screws provided (fig. 2). Using the boiler as a template,
mark all three fixing holes (A. fig. 3). Drill and plug the
wall. For walls in excess of 6 in. terminal may now be fitted from within the building, if required, by passing it
through the wall liner before fitting the boiler to the wall.
TAKE CARE NOT TO ALLOW THE TERMINAL TO
FALL. Attach the chains onto the hooks inside the walls
liner (fig. 4).
Attach the self adhesive foam gasket to the flat surface
of the boiler around the air inlet spigot on the back of the
boiler. Pull off the protective paper whilst sticking down
the gasket. Lift the boiler into position with the air inlet
spigot locating in the wall liner. Secure the boiler to the
wall using the screws and washers provided. If not previously fitted, fit the terminal from the outside. For walls
between 3 in and 6 in thickness the chains may be located
in the slots provited in the brackets on which the flue
hood is fitted (b. Fig. 3).
Slide the flue duct through the wail liner and engage it in
the terminal by at least 25 mm (1 in) and fully onto the
flue bend. The duct may have to be cut to length and fitted with seam uppermost. Replace the flue bend and
secure with the two screws. Ensure that the seal between
the heat exchanger and the flue bend is made evenly and
securely.
4.3.2.
Open Flue Version
The boiler is attached to.the wall by a bracket at the top
the boiler and by two screws at the bottom.
Using the dimensions detailed in 2. TECHNICAL
DATA, mark the position of the fixing holes for wall
mounting plate ensuring adequete space for connection
to the flue pipe.
Remove the boiler cover by pulling off the gas control
knob and removing the screw below it. pull the bottom
of the cover forwards then lift off.
Hang the boiler on the wall bracket and mark the positions of the two bottom fixing holes. Drill and plug the
wall. Rehang the boiler and screw in position.
Connect the flue to the draught diverter outlet making a
good seal between the spigot and flue pipe.
4.4.
Gas Connections
The gas service tap must be fitted as in fig. 5 together
with the filter/washer. The gas supply pipe size should be
sufficient to ensure that there is 8 in.w.g. gas pressure at
the service tap when working.
4.5.
Water Connections
The water flow pipe is on the left hand side of the boiler
and the water return pipe on the right as indicated in 2.
TECHNICAL DATA.
The balanced flue version has a built-in facility for top
connection;
To avoid damage to the internal pipework it is recommended that the unions are held whilst screwing fittings
on to the flow and return connections. Where the top
connection is used remove the plugs from the two top
connections. Remove unions from the bottom connections, re-fit the unions in the top connections and transfer the plugs to the bottom connections.
Where bottom outlet connections are used, the blanked
off top outlet connections can be used as air vents when
commissioning.
The open flue version has no purpose made facility for
top connections, but recesses are provided on both sides
of the boiler frame to allow pipes to rise within the boiler
dimension as shown in 2. TECHNICAL DATA.
‘I
Page 7
installation
4.6.
Electrical Connections
The CORVEC 28 has no electrical connections and all
external electrical controls should be wired to control the
circulating pump.
Most normal pumped primary control schimes can be
used, including non-electrical heating and hot water controls.
fig 6
fig 7
fig 8
fig 9
fig 10
fig 11
<
fig 12
Hot Water only
Pump, Time Clock and Cylinder Thermostat
Heating only
Pump, Time Clock and Room Thermostat
Hot Water and Heating
Pump Programmer, Room/Cylinder Thermostat and Flow Share Valve
Hot Water and Heating
Pump, Programmer, Room/Cylinder thermostats and two Motorized Valves.
Hot Water and Heating
Pump, Time CIock and Non-Electrical Hot
Water and Heating Controls
Hot Water and Heating
Pump, Time Clock, Non-Electrical Hot Water
Control and Electrical Heating Control
Hot Water and Heating
Pump, Time Clock, Non-Electrical
Heating
Control and Electrical Hot Water Control
The following diagrams show typical control schemes
using electrical controls only.
TIME CLOCK
CYLINDER
PIMP
THERMCSTAT
TIME CLOCK
Row TMERYOSTAT
PlM?
ROON THERMOSTAT
The following diagrams show typical control schemes
using electrical/non-electrical controls.
TIME CLOCK
PlMP
MOTOEIZED C/H VALVE
ROOM THERMOSTAT
PWP
TIME CLOCK
CYLINDER I7lERMOSTA.T
It is not normally possible to use full programming ficilities when using a mixture of electrical an.d non-electrical
controis, but some non-electrical hot water controls are
-now available with an external micro-switch which would
allow the scheme as in fig. 11 to be fully programmed.
Page 8
installation
5) WATER CIRCULATING SYSTEM
5.1.
General
The CORVEC 28 is a low water content boiler designed
only
for use with fully pumped systems. It may
be
used
with open or sealed systems, all safety controls excluding
the pressure relief valve being incorporated in the boiler.
The thermostat is set to give a nominal 82” C (180” F)
flow temperature and is not adjustable. Thermostatic
control must be fitted to the cylinder and heating cir-
cuits.
5.2.
Control Schemes
The boiler does not incorporate electrical controls or
connections, the primary control being provided by the
pump, the operation of which will light the boiler, providing that there is a minimum flow of 450 l/h (1.65 gpm).
Most normal pumped primary control schemes can be
used including thermostatic radiator and cylinder valves.
When using motorized valves, the systems control should
.be designed to switch off the pump when all circuits are
satisfied.
For details of wiring and of control schemes, see 4.6.
Chaffoteaux Limited should be consulted where techni-
cal assistance is required.
5.3.
Isolating Valves
Two isoiating valves should be fitted adjacent to the boiler to allow full servicing facilities. Where the circulating
pump is adjacent to the boiler and is provided with isolating valves, it is only necessary to fit one isolating valve
in the boiler flow. Fig. 13 shows a typical pipework
arrangement.
5.4.
Circulating
Pump
The circulating pump should be fitted in the return as shown
in fig. 13. and should be sized to overcome the hydraulic ie-
sistance of the boiler and system. The boiler requires a mini-
mum flou r;ltc of.380 I h (I .39 gpm) its correct operation and
at this flow has a resistance of 3.1 metres ( 10.5 ti.) See graph.
350 400 450 500 550
FLOW RATE
Litres/hour
Where it is impossible to fit the pump in the return. It
may be fitted in the flow as shown in fig 14, providing
that there is a minimum of 2 metres (6.5 ft) static head
between the water level in the feed and expansion tank
and the top of the boiler casing.
5.5.
System
By-Pass
A
valved system by-pass as shown in figs 13 and 14 may
be required to ensure adequate water flow through the
boiler. The by-pass should be a 15 mm (l/2 in) pipe with
a suitable balancing valve.
5.6. 1
utoma:ir
:i.ir Separators
ChaffoteatiA ~iau;cti ~o.:gly recommend the inclusion
of a British Gas accepted automatic air separator in the
system as shown in fig I3 and 14.
Where an air separator is not fitted, the open vent pipe
should rise continuously from the pump inlet and the
common return be introduced at right angles to this pipe.
The preferred arrangement is shown in fig 15.
5.7.
Open Systems Only
5.7.1.
Cylinder .
The domestic hot water cylinder used with the CORVEC
28 must be of the indirect coil and high recovery type.
Flow and return pipework to the cylinder should be in 22
mm pipe.
5.7.2.
Feed and Expansion Tank
The feed and expansion tank should be connected as
shown in figs 13 or 14 and should not be mounted closer
than 9 ins to a ceiling to allow access to the ball valve.
The minimum static head for the CORVEC 28 should be
0.15 (6 “) for the pump on the return (fig. 13) and 2
metres (6.5 ft) for the pump on the flow (fig. 14).
5.8.
Sealed System Only
5.8.1.
Safety Valve
A safety valve shall be fitted close to the appliance on the
flow pipe by a horizontal or a vertically upward connection. Only safety valves set’to operate at 3 bar shall be
used; they shall be so positionned, or any discharge pipe
so arranged, that discharge of water or steam from the
valve cannot create a hazard to occupants of the premises
or cause damage to electrical components and wiring.
5.8.2.
Pressure Gauge
A pressure gauge covering at least the range O-4 bar
(O-60
1 b/irP) shall be fitted to the system adjacent to, and visi-
ble from, the filling point.
8
Page 9
installation
AIR
SEPARATOR
6 ins
TO BOILER
PUMP
.
. .
E
.*.:.:...:.*.:,
.
.e.*.*.*.-.*.
4
E
G
-E
E
ua
6ins -
150%
Fig. 15
,
9
Page 10
installation
5.8.3.
Expansion Vessel
(i) A diaphragm type expansion vessel shall be fit-
(ii) The nitrogen or air charge pressure of the
ted by a connection to the inlet side of the circu-
expansion vessel shall be not less than the
lating pump, in a manner laid down in the vessel
hydro-static head (height of the top point of the
maker’s instructions (see fig 16 for illustration
system above the expansion vessel).
of recommended system layouts). The expansion vessel shall be capable of accepting water
(iii) The expansion vessel shall be sized in accor-
up to at least 62.5 % of its volume without
dance with the following Table.
damage.
Air or nitrogen charge
Expansion Vessel Volume (litres)
pressure (bar*, gauge)
0.5
1.0
Pre-pressurisation
pressure (bar*, gauge)
None
i 3
None 1.5
System Volume
Litres
Gallons
20
4.4
1.4
2.4
1.8 3.3
40
8.8
2.8
4.9
3.7
6.6
60
13.2
4.2
7.3
5.4
9.8
80
17.6
5.6
9.8 7.3
12.3
100
22.0
7.0
12.2
9.1
16.4
120
26.4
8.4
14.6
11.0
19.7
140
30.8
9.8
17.0 12.8
23.0
160
35.2
11.2
19.4 14.6
26.2
180
39.6
12.6
21.9
16.4
29.5
200
44.0
14.0
24.3
18.2
32.8
l 1 bar
14.5 lb.f/in2 (Approx. 1 atmosphere or 34 feet head of water).
Where a vessel of the calculated size is not obtainable, the next available larger size should be used.
For the purpose of the above calculation, the volume of the system shall be determined as accurately as possible using
manufacturers’ data as appropriate. Alternatively the volumes given below may be used to give a conservative estimate
of the system volume :
Low water capacity boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
0,8 litres (0.18 gallons)
Small borepipework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
0.3 litres (0.07 gallons) per 0.292 kW
(1000 Btu/h) of system output.
Microbore pipework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ .
Steel panel, radiators . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . .
7 litres (1.5 gallons)
2.3 litres (0.5 gallons) per 0.292 kW
(1000 Btu/h) of system output.
Hotwatercylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 litres (0.44 gallons) .
If a system if extended, an expansion of increased volume may be required unless previous provision has been made for
the extension.
ill
Page 11
installation
DIAGRAMSSHOWING
SYSTEMLAYOUT
1 - Gcpmsion vessel
2 - Pmmm 9-e
3 - Filling point
4. - Drain code
5 - Airrdmsopoint
6 - 6dtyvalva
7 - Topup bottle
PUMP ON THE FLOW
Fig. 16
PUMP ON THE RETURN
5.8.4.
Hot Water Storage Cylinder
The hot water cylinder shall be the indirect coil type
which is suitable for the system pressure.
5.8.5.
Make-Up System
Provision shall be made for replacing water lost from the
system either :
(i) From a make-up vessel or tank mounted in a
osition higher than the top point of the system,
and connected through a non-return valve to
the
system on the return side of the hot water
cylinder or the return side of all heat emitters,
or.
(ii) Where access to a make-up vessel would be dif-
ficult, by pressurisation of the system.
5.8.6.
Mains Connection
There shall be no connection to the mains water supply
or to the water storage tank supplying domestic water,
even through a non-return valve, without the approval of
the local Water Authority.
5.8.7.
Filling Point
The system shall be fitted with a filling point at low level,
which shall have a stop valve to BS 1010, a test cock, an
anti-vacuum valve and a non-return valve approved by
the National Water Council in this order from the system
to the mains.
5.8.8.
Pipework
Pipework should be of copper; small bore or microbore
with capillary or compression jointing to a high standard. Leak sealant shall not be used in the system.
5.8.9.
Feed and Expansion System
Except as provided for above, the expansion cistern and
cold feed required for systems shall not be fitted to sealed
systems.
11
5.9.
Inhibitors
Chaffoteaux Limited do not generally recommend the
inclusion of an inhibitor with heating and hot water
systems, utilizing the CORVEC boilers. It is, however,
appreciated that the specification for a new installation
may require the addition of an inhibitor and the following are the appliance manufacturers recommendations.
(i) Use only a British Gas approved inhibitor.
(ii) Use only the quantities specified by the inhibi-
tor manifacturer.
(iii) Add the inhibitor only when the system has all
air removed.
6) COMMISSIONING AND TESTING
6.1.
Electrical Installation
Checks to ensure electrical safety should be carried out
by a competent person.
6.2. Gas Installation
The whole of the gas installation, including the meter,
should be inspected and tested for soundness and purged
in accordance with the recommendations of CP 331 : 3.
6.3. Water Circulation System
6.3.1. Open System Only
The whole of the system should be filled and thoroughly
flushed out with cold water without the pump in posi-
tion. Ensure that all valves are open.
With the pump fitted, the system should be filled and air
locks cleared. The boiler water section can be vented if
necessary by unscrewing the knurled nut on the drain
valve (see 6.7.) and the top outlet plugs (see 4.5.). Vent
all radiators and check for water soundness.
Light the boiler as detailed in 6.4.
The water system should be heated maximum to working
temperature and examined for water Soundness. Both
gas and water should then be turned off and the water
system rapidly drained while still hot.
Page 12
installation
The system should again be filled, cleard of air locks
and examined for water soundness.
Add inhibitor to the system if required in the specification (see 5.9.)
6.3.2.
Sealed System Only
The whole of the system should be filled and thoroughly
flushed out with cold water without the circulating pump
in position. Ensure that all valves are open. (The system
must be filled with water either from a sealed system filler pump with a break tank, or by any other method
approved by the local Water Undertaking).
With the circulating pump fitted, the system should be
filled and air locks cleared until the pressure gauge registers 1.5 bar (21.5 lbf/in’). (The boiler water section can
be vented if necessary by unscrewing the knurled nut on
the drain valve, see 6.7). Vent all radiators and check for
water soundness.
Manually raise the water pressure to ensure that the
safety valve lifts. This should occur within f 0.3 bar
(+ 4.3 lbf/inZ) of the preset lift pressure, i.e 3 bar (43.5
lbf/ir?).
Release water from the system until the initial system
design pressure is attained, taking into account any difference in height between the pressure gauge and the point
at which the pressure vessel in connected.
Light the boiler as detailed in 6.4.
The water system should be heated to maximum working
temperature and examined for water soundness. Both
gas and water should then be turned off and the water
system rapidly drained whilst still hot.
The system should again be filled, cleared of air locks
and adjusted to the initial system design pressure. Any
set pointer on the pressure gauge should be set to coincide with the indicating pointer. Examine for water
soundness.
Add inhibitor to the system if required in the specification (see 5.9.).
6.4.
Lighting the boiler
The following procedure should be followed :
(a) Check that the gas service tap is open.
(b) Replace the gas control knob.
(c) Turn the gas control knob in an anticlockwise
direction which will automatically light the pilot
N.B. it may necessary to wait a few moments for gas
to reach the pilot.
(d) Wait 15 seconds, then turn the gas control knob
slowly, fully, in an anticlockwise direction. If
pilot is extinguished for any reason, wait 3
minutes before lighting.
(e) The boiler is now ready to operate and will light
when water is pumped through.
(f) Test for gas soundness.
(g) Check and, if necessary, adjust the gas rate as
detailed in 6.5.
6.5.
Gas rate Adjustment
The boiler is not fitted with a governor.
To obtain the riquired output, it may be necessary to
change the restrictor situated in the burner manifold (fig.
17). To alter the heat output remove the pilot supply tube
and the two screws securing the burner manifold to the
burner assembly. Replace the restrictor
with
the required
size as detailed in TECHNICAL DATA. Replace the
burner manifold and pilot tube.
Since the opening of the gas valve depends upon water
flow rate, make the above adjustment when all the air is
removed from the system and all radiator valves are fully
open.
Mark the data badge in the line “SET TO” (against output) to which the boiler has been adjusted. The data
badge is situated inside the case.
6.6.
Balancing the System By-Pass
The system by-pass should be balanced as the final part
of commissioning.
1.
A system by-Pass is not required for the safe
operation of the boiler. which will automatically shut down if the flow rate drops below
450
l/h (1.65 gpm). If however the system may
be required to be used with a large reduction of
heat output at certain times i. e. a reduced number of radiators, then a 15 mm system by-pass
should be used valve and turn off the required
number of radiators to suit the customer’s
needs then open the by-pass until the boiler
lights.
2.
Check system on hot water only. Open by-pass
furher if necessary to obtain correct operation.
6.7.
Draining the Boiler
Close the valves in the pipework connecting the boiler to
the system (fig. 13 or 14). Drain the boiler unscrewing the
knurled nut on the drain valve. F. Fig. 20.
7) BOILER CASE ASSEMBLY
7.1.
Balanced Flue Version
Fit front cover and refit securing screws at the top and
bottom and immediately under the gas control.
Push on gas control knob.
7.2.
Open Flue Version
Fit case and refit securing screw immediately under the
gas control. Push on gas control knob.
Hand the USER’S INSTRUCTIONS to the user for
retention and instruct in the operation of the boiler.
Advise the user of the precautions necessary to prevent
damage to the system and to the building in the event of
the system remaining inoperative during frost conditions.
Finally advise the user that, for continued efficient and
safe operation of the boiler, it is important.that adequate
servicing is carried out at regular intervals recommended
by the local Gas region.
12
Page 13
servicing requirements
9) SERVICING REQUIREMENTS
Remove the heating body.
Clean the heating body by brushing with hot water and
detergent. Do not attempt to clean the internal water-
ways of the heating body without prior consultation with
the manufacturer. Before replacing heating body, see
9.1.3. Replace in reverse order, using new washers where
applicable.
For efficient and trouble free operation it is important
that the CORVEC 28 receives regular maintenance. The
following schedules are recommended.
Before commencing any work, turn off the gas at the gas
inlet tap and isolate the boiler from the water circulating
system (see 5.3.). Ensure that the electricity supply to the
system is switched off. Remove the front cover as detai-
led in 4.3.1. or 4.3.2.
9.1.
Annual Service
9.1.1.
Clean the Burner (fig. 17).
Unscrew the pilot tube clamping screw A, and remove
the clamp and tube. Remove the burner manifold by uns-
crewing fixing screws B. Pull burner head assembly forward to remove, taking care not to trap the thermocouple or ignitor wires. Invert the burner head and clean by
brushing. Replace in reverse order ensuring that the burner head is correctly located on the spigots at the rear,
and that the gasket between the burner manifold and gas
section is in place.
9.1.2.
Clean the Heating Body
Remove the flue bend on balanced flue versions as detailed in 4.3.1.
Drain the boiler as detailed in 6.7.
Remove burner as detailed in 9.1 .l .
Remove the two wires from the fusible link overheat carrier taking care not to lose the nuts and washers.
B.F. Model - Remove the screw holding the bottom of
the heating body skirt to rear case.
Release the union nuts joining the heating body legs to
the water section.
O.F. Model -
Remove the screw holding the bottom of
the heating body skirt and clamping
plate to the rear case.
Release the union nuts at each end of the pipes connecting to the heating body legs and remove.
9.1.3.
Clean the Pilot Assembly. Thermocouple and
Spark Electrode.
Unscrew the pilot tube clamping screw and remove the
clamp and tube. Blow through the tube to remove any
dust. Remove the burner as in 9.1-l.
Unscrew the pilot body (C - fig 18) with a 15 mm or
adjustable spanner. It may be necessary to remove the
heating body (9.1.2.) if this has already been replaced.
Clean the pilot body by blowing or washing. Do not
clean the holes with a wire.
Disconnect the thermocouple from the overheat terminal
stud. With a 7 mm box spanner, unscrew the nut holding
the thermocouple into the gas section (D fig. 19). Thread
the thermocouple and wire up through the gas section.
Clean the end of the thermocouple by brushing.
Remove the spark electrode fixing screw (E - fig 19)
with a cruciform head screwdriver.
Pull off the electrode cable from the piezo ignitor.
Lift the electrode out of the gas section. Clean the end of
the.eiectrode by brushing. Blow any dust off the gas section.
Replace all parts in reverse order and ensure that the slot
in the electrode cable connector is vertical when pushed
onto the piezo ignitor. The pilot flame is non-adjustable.
When burning correctly, the flame should be 3/16”to
l/4” (5-7 mm) high, reaching half way up the exposed
part of the thermocouple.
9.1.4.
Clean the Gas Filter
Unscrew the union nut attaching the gas inlet tap to the
appliance. Lower the union nut and withdraw the filter
which also acts as a washer. Clean the filter by blowing
or washing in water. Do not use any solvents. replace in
reverse order.
Fig. 17
Fig. 18
13
Fig. 19 :
Page 14
servicing requirements
9.1.5.
clean the Thermostat Capsule and Water Filter
Drain the boiler as detailed in 6.7.
Using a 14 mm spanner or adjustable spanner, remove
the thermostat housing cover (G fig. 20) taking care not
to lose the spring. Remove the thermostat capsule and
clean with soap and water. Replace in the reserve order.
Remove union nut (circled figs. 20 and 2Oa) remove and
clean water filter.
9.2.
General service
9.2.1.
Clean Burner, Heriting
Body,
Pilot Assembly
and Thermocouple.
As detailed 9.1.1. - 9.1.3.
9.2.2.
Replace the Gas Filter
As
detailed in 9.1.4.
.9.2.3.
Replace the Diaphragm
Drain the boiler as detailed in 6.7.
Unscrew the four water union nuts (A - fig. 21) on the
water section and remove the high & low pressure tubes.
Unscrew the 4 screws (B -
fig 21) holding the water section to the gas section. Note the relative positions of the
gas and water sections and the two halves of the water
section. Unscrew the two screws holding the water section clamp.
Remove the water section complete with the diaphragm
and bearing plate. Separate the top and bottom halves of
. the water section by removing the eight screws.
Remove diaphragm and discard. Wash out water section.
Replace with a new diaphragm fitted and the bearing
plate positioned on the top of the diaphragm.
Reassemble with the components in their original relative
positions.
Remove the two screws at the rear of the burner holding
it to the rear case.
Remove the four fixing screws fastening the top of the
gas section to the base.
N.B. Provided isolating valves are fitted it may be found
easier if the heating body is removed.
Lift the gas section top off the base.
Remove the gas valve spring.
Lift out the gas valve.
Do not attempt to further dismantle the valve assembly.
Clean the valve seating and replace the gas valve facing
rubber if necessary.
Replace in reverse order.
10.1.
To replace the Thermosiectric Valve.
Remove the therthiiceuple nut (H fig. 20).
Unscrew cap from the side of the gas section and with-
draw the thermo-electric valve. replace if necessary.
Reassemble in reverse order.
10.2 To
replace the
Fusible Link.
Remove the two nuts securing the thermocouple leads to
terminals of the overheat assembly.
Remove clamping disc.
Remove fusible link.
Replace the fusible link. When forming the wires to
shape, avoid bending them close to their entry into the
fuse.
Use long nosed pliers to support the wire.
Reassemble in reverse order.
10.3.
To
replace
the Piezo Ignitor Cartridge
Pull off the electrode lead from the cartridge.
Remove the screw holding the gas control cam.
Pull the cam off the spindle.
Remove the two screws holding the retaining plate in
position.
9.2.4.
Clean the gas Valve
Remove the burner as in 9.1-l.
Disconnect the thermocouple from the overheat terminal
Remove the plate and then the Piezo cartridge.
Replace in reverse order, note the slot in the end of the
electrode cable is vertical when pushed on to the Piezo.
stud and pull off the electrode cable from the piezo ignitor.
Fig. 20
Fig.20
a
14
Page 15
fault finding chart
FAULT
POSSIBLE CAUSE
REMEDY
Pilot will not light
Pilot lights with taper but not
with igniter
Pilot goes out
Main burner will not light or
lights at low rate
Main burner “lifts”
Gas supply not turned on.
Gas supply pipes not purged of air.
Fusible Link open circuited.
Fusible Link shorting to earth.
Turn on.
Purge.
Replace.
Re-position.
Spark electrode wrongly positioned.
Spark from electrode not jumping to thermocouple.
Re-position.
Electrode lead detached from Piezo igniter
Refit.
Electrode lead damaged causing local short circuit
Replace.
Faulty Piezo Ignitor.
Replace.
recirculation.
Flue set wrongly fitted causing re-circulation.
Fusible Link fused.
Securing nuts loose.
Insulation washers fitted incorrectly.
Low meter pressure.
Pilot flame too soft.
Pilot too small, injector blocked.
Thermocouple/thermo-electric valve faulty,
Replace or wash in solvent.
low MV output
Thermocouple loose.
Replace.
Terminal wrongly positioned causing
Tighten.
Installer to resite boiler.
Fit correctly.
Replace.
Re-tighten.
Refit.
Gas Region to adjust.
Clean pilot tube or replace pilot
injector.
Low flow rate pump duty not sufficient.
Water Filter blockad.
Low flow rate system very restrictive.
Low flow rate, air in system.
Water section spindle bent or dry.
Diaphragm split or stretched.
Thermostat not seated properly.
Gas supply insufficient.
Heat exchanger blocked.
Pump speed too slow.
Inspect clean.
Check working pressure 8 in. w.g.
at service tap.
Descale or replace.
Adjust.
Flow and return pipes crossed or plaster,
cement in pipes.
Rectify.
Installer to check pump data.
Clean.
Open system by-pass.
Purge thoroughly, fit air separator
if persistent or wher convectors are
used a head emitters.
Replace or grease.
Replace.
Re-circulation of flue products.
Remove flue set and fit correctly.
Terminal badly sited and flue set wrongly
assembled
Reflit .
Terminal not fitted in wall liner.
Over-gassed.
Fit correctly.
Check sealing of blue.
Adjust set to correct gas rate.
Re-seal fit correctly.
15
Page 16
Imp. Chaffoteaux et Maury
FM. 92220-l 18 - 1182
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