Chaffoteaux & Maury CORVEC 28 OF User manual

chaffoteaux ltd.
CORVEC 28 OF
BF GC No 41 980.28
CORVEC 28 BF
OF GC No 41 980.27
installation
servicingrequirements
Leave these instructions at or near the service Gas Meter.

contents
Page 3 : TECHNICAL DATA
The CORVEC 28 is a wall mounted, low water content
boiler available in both balancedflue and ouen flue ver-
sions. The boiler is rated at 4 kW (13660Bt&h) 6.5 kW
(22350Btu/h) or 8.2 kW (28000btu/h).
Pages 4, 5, 6, 7, 8,
9,10,11 and 12 : INSTALLATION
The boiler is designed for use with Natural Gas only,
unlessotherwise stated.
Pages 13 and 14
Page3 15
Pages 17
: SERVICING
REQUIREMENTS
: FAULT FINDING CHART
: SHORT LIST
A pump must beinstalled in the water circulation system
irrespectiveof whetherthe systemis of the openor sealed
type.
TheCORVEC 28balancedflue versionis suppliedin two
cartons, one containing the boiler and the other contai-
ning the balanced flue set. The CORVEC 28 open flue
version is supplied in one carton.
The guaranteeon this is voidable if it is not installed in accordancewith the recommendationsmadehereinor in amanner
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

technicaldata
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. - Theseboilersaresuppliedwith the8.kW (28000Btu/h)output restrictorfitted. Otherrestrictorsarein anaccompa-
nyingcarton.See6.5
CLEARANCE FOR INSTALLATION AND SERVICING
,alancedflue version :
Sides................................ 25mm (1ins)
Top ................................ 76 mm (3 ins)
Bottom ............................ 127mm (5 ins)
Front ............. .:
............ 600mm (23.6 ins)
Open flue version :
Sides................................ 76mm (3ins)
Top ................................ 76mm (3 ins)
Bottom.. .............................. 127(5ins)
Front ........................... 600mm (23.6ins)
FLUE CONNECTION
Balanced flue version : Open flue version :
Flue set requires a hole in the wall 125mm high x 240 Requiresa nominal 100mm (4in) flue pipe. No split col-
mm wide (6.9 insx 9.4ins) lar is required. Draught diverter is integral.
GAS CONNECTION : R l/2 in. (112in. BSP taper male)
WATER CONNECTIONS : Flow : R 314. 314BSP on left hand side of boiler viewed from front.
Return : R 314. 3/4 BSP.
‘he open flue version hasmale threads (R 3/4), the balancedflue, female threads (Rc 3/4).
MINIMUM WATER FLOW RATE : 450L/hr. 1.65gpm.
MINIMUM STATIC HEAD AT BOILER : 0.15 Metre (6 ins) Seesection 5.
MAXIMUM STATIC HEAD AT BOILER : 30 Metres (98 ft).
ELECTRICAL CONNECTIONS : None on the boilers (all control via pump etc.)
DIMENSIONS
Balancedflue version : Open flue version :
600 mm high x 269mm wide x 218mm deep 600 mm high x 269 mm wide x 218mm deep
(23.6 ins x 10.6ins x 8.6 ins) (23.6 ins x 10.6ins x 8.6 ins)
WEIGHT : 13.6kg (30 lbs)
WATER CAPACITY : 0.182litres (0.04 gals)
A 6 blade Chaffoteaux burner is usedfitted with 1.18mm dia injectors. The non-adjustable permanentpilot is manually
ignited by a piezoignitor. The flow temperatureis controlled by a non-adjustable thermostat at a nominal 82” C (ISO F).
3

installation
&INSTALLATION
. General REQUIREMENTS
The installation of the boiler must bein accordancewith
the GasSafety Regulations, Building Regulations, I.E.E.
Regulationsand the Byelawsof the local Water Underta-
king. It should be in accordancealso with BS Codesof
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 chosenfor the boiler should permit the pro-
vision of a satisfactory flue termination. The position
should also provide adequatespacefor servicing and air
circulation around the boiler.
Whereinstallation will bein an unusual position, special
procedures may be necessary,and BS 5376: 2 gives
detailed guidance on this aspect.
A cupboard or compartment usedto enclosethe boiler
must be designed and constructed specifically for this
purpose. An existing cupboard or compartment may be
usedprovided that it is modified for the purpose.
Details of essential features of cupboard/compartment
designare 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 adequatecapacity to
meetthe total gasload, i.e. boiler plus other gasapplian-
CeS.
Ensurethat the pipework from the meter to the boiler is
of adequatesize. Do not usepipesof a smaller sizethan
the boiler gasconnection.
Thecompiete installation must betestedfor soundnessas
describedin the above Code.
3.4. Fiueing
Detailed recommendations for flueing are given in
BS5440: 1.
The following notesare for generalguidanceonly.
3.4.1. Balanced Flue Version
The boiler must beinstalled sothat the flue terminal dis-
chargesdirectly into the external air.
Termination should be on a clear expanseof wall; the
terminal being preferably not lessthan 600 mm (2 ft)
from a corner, recessor projection.
(a)
(b)
(cl
Within 300mm (1ft), measuredvertically, from
the bottom of an openablewindow, air vent or
any other ventilation opening.
Lessthan 300mm (1 ft) from ground level.
Lessthan 600mm (2 ft) from any surfacefacing
the terminal.
(4
Immediately beneatheavesor a balcony.
Where the terminal is lessthan 2 m (6.6 ft) above the
level of any ground, balcony, flat roof or placeto which
people have access,the terminal must beprotected by a
guard of suitable material.
Where a terminal guard hasnot beensupplied (optional
extra) with the boiler, onemay beobtained 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 besited suchthat the maximum possi-
ble length of the flue system.canbecontained within the
building and that the route of the flue risescontinuously
to the terminal and is asdirect as praticable.
Where 600mm (2 ft) of flue pipe should rise vert ically
from the draught diverter connection before the useof
any bendsor elbows.
Horizontal or shallow angleruns, right angledbendsand
mitred elbows should be avoided.
Where an existing brick chimney is to beused,it should
besweptthoroughly beforeconnection of the newboiler,
and the chimney should be lined.
An approved British Gasterminal must befitted andthe
terminal sitedat the adjacentroof edge,andwherepossi-
ble abovethe ridge line. The flue must not beterminated
at or adjacent to a wall face.
3.5. Air Supply
Detailed recommendationsfor air supply aregivenin BS
5440 : 2.
The following notes are intended to give general gui-
dance.
3.5.1. Balanced Flue Version
The room in which a balanced flued boiler is installed
doesnot require a purpose provided air vent.
Where a balancedflued boiler is installed in a cupboard
or compartment, air ventsarerequired (for cooling pur-
poses)in the cupboard or compartment at high and low
level. Theseair 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

installation
3.5.2. Open Flue Version
3.5.2.1. Room or Internal Space Air Supply
Where the boiler is to beinstalled in a room or internal
space,the boiler requiresthe room or internal spacecon-
taining it to havea permanentair vent. This vent mustbe
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 sizedirect to outside air.
The minimum effective areaof the permanentair vent(s)
is related to the maximum rated input of the boiler and
should be 15cm’ (2 in’).
3.5.2.2. Cupboard or Compartment Air Supply
Where the boiler is to beinstalled in a cupboard or com-
partment permanent air ventsare required (for combus-
tion, flue dilution and cooling purposes)in the cupboard
or compartment at high and low level. Theseair vents
must either communicate with a room or internal space
or be direct to outside air.
The minimum effective areasof 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 180cm’ 90 cm2
Level
28 in2 14in*
Note : Both air vents must communicate with the same
room or internal spaceor must both beon the samewall
to outside air.
Where cupboard or compartment air ventscommunicate
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 adequateair inlet area from
outside is not provided, spillageof the products from the
boiler flue could occur when the extract fan is in opera-
tion. Where such installations occur, a spillage test as
detailed in BS5440 : 1must becarried out andany neces-
sary action taken.
3.6. Water Circulation Systems
Openor sealedtype central heating systemsshould bein
accordancewith the relevant recommendations given in
BS 5376: 2. BS 5449: 1 (for smallbore or microbore
systems)and the British Gaspublication entitled (( Mate-
rial and installation Specifications for DomesticCentral
Heating and Hot Water 1).
Hot water systemsshould bein accordancewith the rele-
vant recommendationsgiven in CP 342: 1andtheabove
mentioned British Gas publication and BS 5546.
3.7. Electrical Supply
The CORVEC 28 boiler has no electrical connections,
but all wiring externalto theboiler must bein accordance
with the I.E.E. Regulations.
For external wiring instructions, see4.6. Electrical Con-
nections.
4) INSTALLATION OF BOILER
4.1. General
A vertical flat area is required for the boiler asfollows.
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 caseremoval and for air move-
ment.
4.2. Fheing
4.2-l. Balanced Flue Version
The standard flue setsupplied with the boiler is suitable
for walls having a thicknessof 75 mm to 355mm (3 ins
14ins). (Fluesetsfor walls of thickness upto 610mm (24
in) are available to specialorder).
Using the boiler asa template determinethe position for
the flue duct. The following procedure should now be
followed.
(a)
Preparethe Wall
Cut a hole in the wall which measures20 mm
high x 240 mm wide (4 l/2 x 9 l/2 in). If the
holeiscut accurately, thereis no needto line the
hole, since the wall liner make a satisfactory
seal.
(b)
Preparethe Parts
Cut the wall liner to the samelength asthe wall
thickness. Cut the flue duct to the samelength,
plus 80 mm (3.25 ins).
(cl
Fit the wall Liner (fig. 1) (seepage6).
Position the wall liner in place. Ensurethat 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
surfacesaround the liner with cement.
5

installation
4.2.2. Open Flue Version
The CORVEC 28open flue version hasa draught diver-
ter outlet suitable for a nominal 100mm (4 in flue pipe).
The flue should beinstalled in accordancewith the requi-
rements of BS 5440: 1.
4.3. FITTING THE BOILER
4.3.1. Blanced Flue Version
Pull off the gascontrol knob. remove the screw below
the gascontrol knob and thetwo screwstop and bottom.
Removethe front cover by pulling forwards.
Removethe Flue Bend from the top of the heatexchan-
ger (two screws).
Fix the top bracket to the rear boiler case using the
screwsprovided (fig. 2). Using the boiler as a template,
mark all three fixing holes(A. fig. 3). Drill and plug the
wall. For walls in excessof 6in. terminal may now befit-
ted from within the building, if required, by passingit
through the wall liner beforefitting the boiler to the wall.
TAKE CARE NOT TO ALLOW THE TERMINAL TO
FALL. Attach the chainsonto the hooks insidethe walls
liner (fig. 4).
Attach the self adhesivefoam gasketto the flat surface
of the boiler around theair 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. Securethe boiler to the
wall using the screwsand washersprovided. If not pre-
viously fitted, fit the terminal from theoutside. For walls
between3in and 6 in thicknessthe chainsmay belocated
in the slots provited in the brackets on which the flue
hood is fitted (b. Fig. 3).
Slidethe flue duct through the wail liner andengageit in
the terminal by at least 25 mm (1 in) and fully onto the
flue bend. The duct may haveto becut to length and fit-
ted with seam uppermost. Replace the flue bend and
securewith the two screws.Ensure that the sealbetween
the heat exchangerand the flue bendis madeevenlyand
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 screwsat the bottom.
Using the dimensions detailed in 2. TECHNICAL
DATA, mark the position of the fixing holes for wall
mounting plate ensuring adequetespacefor connection
to the flue pipe.
Removethe 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 posi-
tions of the two bottom fixing holes. Drill and plug the
wall. Rehangthe boiler and screwin position.
Connect the flue to the draught diverter outlet making a
good sealbetweenthe 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 gassupply pipe sizeshouldbe
sufficient to ensurethat there is 8 in.w.g. gaspressureat
the servicetap when working.
4.5. Water Connections
The water flow pipe is on the left hand sideof the boiler
and the water return pipe on the right asindicated in 2.
TECHNICAL DATA.
The balanced flue version has a built-in facility for top
connection;
To avoid damageto the internal pipework it is recom-
mendedthat the unions are held whilst screwingfittings
on to the flow and return connections. Where the top
connection is usedremove the plugs from the two top
connections. Removeunions from the bottom connec-
tions, re-fit the unions in the top connections and trans-
fer the plugs to the bottom connections.
Where bottom outlet connections are used, the blanked
off top outlet connectionscan beusedasair ventswhen
commissioning.
The open flue version has no purposemade facility for
top connections, but recessesareprovided on both sides
of the boiler frame to allow pipesto risewithin the boiler
dimension asshown in 2. TECHNICAL DATA. ‘I

installation
4.6. Electrical Connections
The CORVEC 28 has no electrical connections and all
external electrical controls should bewired to control the
circulating pump.
Most normal pumped primary control schimes can be
used,including non-electrical heatingand hot water con-
trols.
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 Thermos-
tat and Flow ShareValve
Hot Water and Heating
Pump, Programmer, Room/Cylinder thermos-
tats 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 possibleto usefull programming ficili-
ties when using a mixture of electrical an.dnon-electrical
controis, but somenon-electrical hot water controls are
-now available with anexternal micro-switch which would
allow the schemeas in fig. 11to be fully programmed.

installation
5) WATER CIRCULATING SYSTEM
5.1. General
The CORVEC 28 is a low water content boiler designed
only for usewith fully pumpedsystems.It may be used
with openor sealedsystems,all safety controls excluding
the pressurerelief valve beingincorporated 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, provi-
ding that there isa minimum flow of 450l/h (1.65gpm).
Most normal pumped primary control schemescan be
usedincluding thermostatic radiator and cylinder valves.
When usingmotorized valves,thesystemscontrol should
.bedesignedto switch off the pump when all circuits are
satisfied.
For details of wiring and of control schemes,see4.6.
Chaffoteaux Limited should be consulted wheretechni-
cal assistanceis required.
5.3. Isolating Valves
Two isoiating valvesshould befitted adjacentto the boi-
ler to allow full servicing facilities. Wherethe circulating
pump is adjacent to the boiler and is provided with isola-
ting valves, it is only necessaryto fit one isolating valve
in the boiler flow. Fig. 13 shows a typical pipework
arrangement.
5.4. Circulating
Pump
Thecirculatingpumpshouldbefitted in thereturnasshown
in fig. 13.andshouldbesizedto overcomethehydraulicie-
sistanceof theboilerandsystem.Theboilerrequiresamini-
mumflou r;ltcof.380I h(I .39gpm)itscorrectoperationand
atthisflow hasaresistanceof3.1metres(10.5ti.) Seegraph.
350 400 450 500 550
FLOWRATE 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
betweenthe water level in the feed and expansiontank
and the top of the boiler casing.
5.5. System
By-Pass
A valved systemby-passasshown in figs 13and 14may
be required to ensureadequatewater flow through the
boiler. The by-passshould bea 15mm (l/2 in) pipewith
a suitable balancing valve.
5.6. 1 utoma:ir :i.ir Separators
ChaffoteatiA ~iau;cti ~o.:gly recommend the inclusion
of a British Gasacceptedautomatic air separatorin the
systemas 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 beintroduced at right anglesto this pipe.
The preferred arrangementis shown in fig 15.
5.7. Open Systems Only
5.7.1. Cylinder .
The domestic hot water cylinder usedwith the CORVEC
28 must be of the indirect coil and high recovery type.
Flow and return pipework to the cylinder should bein 22
mm pipe.
5.7.2. Feed and Expansion Tank
The feed and expansion tank should be connectedas
shown in figs 13or 14and should not bemounted closer
than 9 ins to a ceiling to allow accessto the ball valve.
The minimum static headfor the CORVEC 28shouldbe
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 valveshall befitted closeto the applianceon the
flow pipe by a horizontal or a vertically upward connec-
tion. Only safety valves set’to operate at 3 bar shall be
used;they shall beso positionned, or any dischargepipe
so arranged, that dischargeof water or steam from the
valvecannot createahazardto occupantsof the premises
or causedamageto electrical components and wiring.
5.8.2. Pressure Gauge
A pressuregaugecovering at leastthe rangeO-4bar (O-60
1b/irP) shall befitted to the systemadjacentto, andvisi-
ble from, the filling point.
8

installation
AIR
SEPARATOR
6 ins
TO BOILER PUMP
. . .
E .*.:.:...:.*.:,
.
.e.*.*.*.-.*.4
E
G -E E
ua
6ins -
150%
Fig. 15
,
9

installation
5.8.3. Expansion Vessel
(i) A diaphragm type expansionvesselshall be fit- (ii) The nitrogen or air charge pressure of the
ted by aconnection to the inlet sideof the circu- expansion vessel shall be not less than the
lating pump, in amannerlaid down in the vessel hydro-static head(height of the top point of the
maker’s instructions (seefig 16 for illustration systemabove the expansion vessel).
of recommended system layouts). The expan-
sion vesselshall be capable of accepting water (iii) The expansion vessel shall be sized in accor-
up to at least 62.5 % of its volume without dancewith the following Table.
damage.
Air or nitrogen charge Expansion VesselVolume (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 1bar 14.5lb.f/in2 (Approx. 1atmosphereor 34 feet head of water).
Where a vesselof the calculated sizeis not obtainable, the next available larger sizeshould be used.
For the purpose of the abovecalculation, the volume of the system shall be determinedasaccurately aspossibleusing
manufacturers’ data asappropriate. Alternatively the volumesgiven below may beusedto give a conservativeestimate
of the system volume :
Low water capacity boiler . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0,8 litres (0.18 gallons)
Small borepipework . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 litres (0.07 gallons) per 0.292kW
(1000Btu/h) of systemoutput.
Microbore pipework . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _.
Steel panel,radiators . . . . . . . .. . .. . . . . . . . . . . . . . . _. . . . . . . . . . . . . . . . . . . . . .
7 litres (1.5 gallons)
2.3 litres (0.5 gallons) per 0.292 kW
(1000Btu/h) of systemoutput.
Hotwatercylinder . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 litres (0.44 gallons) .
If asystemif extended,an expansionof increasedvolume may berequired unlessprevious provision hasbeenmadefor
the extension.
ill

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 systempressure.
5.8.5. Make-Up System
Provision shall bemadefor replacingwater lost from the
systemeither :
(i) From a make-up vesselor 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 accessto a make-up vesselwould bedif-
ficult, by pressurisationof the system.
5.8.6. Mains Connection
There shall be no connection to the mains water supply
or to the water storagetank supplying domestic water,
eventhrough anon-return valve, without theapproval of
the local Water Authority.
5.8.7. Filling Point
Thesystemshall befitted with afilling point at low level,
which shall havea 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 stan-
dard. Leak sealantshall not be usedin the system.
5.8.9. Feed and Expansion System
Except as provided for above, the expansioncisternand
cold feedrequired for systemsshall not befitted to sealed
systems.
11
5.9. Inhibitors
Chaffoteaux Limited do not generally recommendthe
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 follo-
wing arethe appliancemanufacturers 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 systemhasall
air removed.
6) COMMISSIONING AND TESTING
6.1. Electrical Installation
Checks to ensureelectrical safety should be carried out
by a competent person.
6.2. Gas Installation
The whole of the gas installation, including the meter,
should beinspectedand testedfor soundnessand purged
in accordancewith the recommendationsof CP 331: 3.
6.3. Water Circulation System
6.3.1. Open System Only
The whole of the systemshould be filled and thoroughly
flushed out with cold water without the pump in posi-
tion. Ensure that all valvesare open.
With the pump fitted, the systemshould befilled andair
locks cleared. The boiler water section can be vented if
necessaryby unscrewing the knurled nut on the drain
valve (see6.7.) and the top outlet plugs (see4.5.). Vent
all radiators and check for water soundness.
Light the boiler as detailed in 6.4.
The water systemshould beheatedmaximum to working
temperature and examined for water Soundness.Both
gasand water should then be turned off and the water
systemrapidly drained while still hot.

installation
The system should again be filled, cleard of air locks
and examined for water soundness.
Add inhibitor to the systemif required in the specifica-
tion (see5.9.)
6.3.2. Sealed System Only
The whole of the systemshould be filled and thoroughly
flushed out with cold waterwithout the circulating pump
in position. Ensure that all valvesare open. (The system
must befilled with water either from a sealedsystem fil-
ler pump with a break tank, or by any other method
approved by the local Water Undertaking).
With the circulating pump fitted, the systemshould be
filled and air locks cleareduntil the pressuregaugeregis-
ters 1.5bar (21.5 lbf/in’). (The boiler water section can
bevented if necessaryby unscrewingthe knurled nut on
the drain valve, see6.7). 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 presetlift pressure,i.e 3 bar (43.5
lbf/ir?).
Releasewater from the system until the initial system
designpressureisattained, taking into account any diffe-
rencein height betweenthe pressuregaugeand the point
at which the pressurevesselin connected.
Light the boiler as detailed in 6.4.
The water systemshould beheatedto 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 pressuregaugeshould beset to coin-
cide with the indicating pointer. Examine for water
soundness.
Add inhibitor to the systemif required in the specifica-
tion (see5.9.).
6.4. Lighting the boiler
The following procedureshould be followed :
(a) Check that the gasservice tap is open.
(b) Replacethe gascontrol knob.
(c) Turn the gascontrol knob in an anticlockwise
direction which will automatically light the pilot
N.B. it may necessaryto wait a few moments for gas
to reach the pilot.
(d) Wait 15seconds,then turn the gascontrol 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 operateand will light
when water is pumped through.
(f) Test for gassoundness.
(g) Check and, if necessary,adjust the gasrate 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 necessaryto
changethe restrictor situated in the burner manifold (fig.
17).To alter the heatoutput removethe pilot supplytube
and the two screwssecuring the burner manifold to the
burnerassembly. Replacethe restrictor with the required
size as detailed in TECHNICAL DATA. Replacethe
burner manifold and pilot tube.
Sincethe opening of the gasvalve dependsupon water
flow rate, make the above adjustment when all the air is
removedfrom the systemand all radiator valvesarefully
open.
Mark the data badgein the line “SET TO” (againstout-
put) to which the boiler has been adjusted. The data
badgeis situated inside the case.
6.6. Balancing the System By-Pass
The systemby-passshould be balancedas the final part
of commissioning.
1. A system by-Pass is not required for the safe
operation of the boiler. which will automati-
cally shut down if the flow rate drops below
450 l/h (1.65gpm). If however the systemmay
berequired to beusedwith a large reduction of
heatoutput at certain times i. e. a reducednum-
ber of radiators, then a 15mm systemby-pass
should be usedvalve 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 systemon hot water only. Openby-pass
furher if necessaryto obtain correct operation.
6.7. Draining the Boiler
Closethe valvesin the pipework connecting the boiler to
thesystem(fig. 13or 14).Drain the boiler unscrewingthe
knurled nut on the drain valve. F. Fig. 20.
7) BOILER CASE ASSEMBLY
7.1. Balanced Flue Version
Fit front cover and refit securing screwsat the top and
bottom and immediately under the gascontrol.
Pushon gascontrol knob.
7.2. Open Flue Version
Fit caseand refit securing screw immediately under the
gascontrol. Push on gascontrol 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 necessaryto prevent
damageto the systemand to the building in the eventof
the system remaining inoperative during frost condi-
tions.
Finally advise the user that, for continued efficient and
safeoperation of the boiler, it isimportant.that adequate
servicingis carried out at regular intervals recommended
by the local Gas region.
12

servicingrequirements
9) SERVICING REQUIREMENTS
Removethe heating body.
Clean the heating body by brushing with hot water and
detergent. Do not attempt to clean the internal water-
waysof the heating body without prior consultation with
the manufacturer. Before replacing heating body, see
9.1.3. Replacein reverseorder, using newwasherswhere
applicable.
For efficient and trouble free operation it is important
that the CORVEC 28 receivesregular maintenance.The
following schedulesare recommended.
Before commencingany work, turn off the gasat the gas
inlet tap and isolate the boiler from the water circulating
system(see5.3.). Ensurethat the electricity supply to the
systemis switched off. Removethe front cover asdetai-
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 andtube. Removethe burnermanifold by uns-
crewing fixing screwsB. Pull burner headassemblyfor-
ward to remove, taking carenot to trap the thermocou-
ple or ignitor wires. Invert the burner headand cleanby
brushing. Replacein reverseorder ensuringthat the bur-
ner head is correctly located on the spigots at the rear,
and that the gasketbetweenthe burner manifold and gas
section is in place.
9.1.2. Clean the Heating Body
Removethe flue bendon balancedflue versionsasdetai-
led in 4.3.1.
Drain the boiler as detailed in 6.7.
Removeburner as detailed in 9.1.l .
Removethe two wires from the fusible link overheatcar-
rier taking carenot to losethe nuts and washers.
B.F. Model - Removethe screwholding the bottom of
the heating body skirt to rear case.
Releasethe union nuts joining the heating body legsto
the water section.
O.F. Model - Removethe screwholding the bottom of
the heating body skirt and clamping
plate to the rear case.
Releasethe union nuts at eachend of the pipes connec-
ting to the heating body legsand remove.
9.1.3. Clean the Pilot Assembly. Thermocouple and
Spark Electrode.
Unscrew the pilot tube clamping screw and removethe
clamp and tube. Blow through the tube to remove any
dust. Remove the burner asin 9.1-l.
Unscrew the pilot body (C - fig 18) with a 15mm or
adjustable spanner. It may be necessaryto remove the
heating body (9.1.2.) if this hasalready beenreplaced.
Clean the pilot body by blowing or washing. Do not
cleanthe holes with a wire.
Disconnectthe thermocouple from the overheatterminal
stud. With a 7mm box spanner,unscrewthe nut holding
thethermocouple into the gassection (D fig. 19).Thread
the thermocouple and wire up through the gassection.
Clean the end of the thermocouple by brushing.
Remove the spark electrode fixing screw (E - fig 19)
with a cruciform headscrewdriver.
Pull off the electrodecable from the piezo ignitor.
Lift the electrodeout of thegassection. Cleantheendof
the.eiectrodeby brushing. Blow any dust off the gassec-
tion.
Replaceall parts in reverseorder and ensurethat theslot
in the electrode cable connector is vertical when pushed
onto the piezo ignitor. Thepilot 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 gasinlet tap to the
appliance. Lower the union nut and withdraw the filter
which also acts asa washer. Clean the filter by blowing
or washing in water. Do not useany solvents. replacein
reverseorder.
Fig. 17 Fig. 18
13
Fig. 19 :

servicingrequirements
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 carenot
to lose the spring. Removethe thermostat capsuleand
clean with soapand water. Replacein the reserveorder.
Removeunion nut (circled figs. 20 and 2Oa)removeand
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 removethe high & low pressuretubes.
Unscrew the 4 screws(B - fig 21)holding the water sec-
tion to the gassection. Note the relative positions of the
gasand water sections and the two halves of the water
section. Unscrew the two screwsholding the water sec-
tion clamp.
Removethe water section complete with the diaphragm
and bearing plate. Separatethetop and bottom halvesof
. the water section by removing the eight screws.
Removediaphragm and discard. Washout watersection.
Replace with a new diaphragm fitted and the bearing
plate positioned on the top of the diaphragm.
Reassemblewith the componentsin their original relative
positions.
Removethe two screwsat the rear of the burner holding
it to the rear case.
Removethe four fixing screws fastening the top of the
gassection to the base.
N.B. Provided isolating valvesare fitted it may befound
easierif the heating body is removed.
Lift the gassection top off the base.
Removethe gasvalve spring.
Lift out the gasvalve.
Do not attempt to further dismantle the valveassembly.
Clean the valve seatingand replacethe gasvalve facing
rubber if necessary.
Replacein reverseorder.
10.1. To replace the Thermosiectric Valve.
Removethe therthiiceuple nut (H fig. 20).
Unscrew cap from the side of the gassection and with-
draw the thermo-electric valve. replace if necessary.
Reassemblein reverseorder.
10.2 To replace the Fusible Link.
Removethe two nuts securingthe thermocouple leadsto
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.
Uselong nosedpliers to support the wire.
Reassemble in reverseorder.
10.3. To
replace the Piezo Ignitor Cartridge
Pull off the electrodelead from the cartridge.
Removethe screw holding the gascontrol cam.
Pull the cam off the spindle.
Remove the two screws holding the retaining plate in
position.
9.2.4.
Clean the gas Valve
Removethe burner as in 9.1-l.
Disconnect the thermocouple from the overheatterminal
Removethe plate and then the Piezo cartridge.
Replacein reverse order, note the slot in the endof the
electrode cable is vertical when pushed on to the Piezo.
stud and pull off the electrodecablefrom the piezo igni-
tor.
Fig. 20 Fig.20
a
14

fault findingchart
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”
Gassupply not turned on.
Gassupply pipes not purged of air.
Fusible Link open circuited.
Fusible Link shorting to earth.
Turn on.
Purge.
Replace.
Re-position.
Spark electrodewrongly positioned.
Spark from electrodenot jumping to thermo-
couple. Re-position.
Electrode lead detachedfrom Piezo igniter Refit.
Electrode leaddamagedcausinglocal short cir-
cuit Replace.
Faulty Piezo Ignitor. Replace.
recirculation.
Flue setwrongly fitted causing re-circulation.
Fusible Link fused.
Securingnuts loose.
Insulation washersfitted incorrectly.
Low meter pressure.
Pilot flame too soft.
Pilot too small, injector blocked.
Thermocouple/thermo-electric valve faulty, Replaceor wash in solvent.
low MV output
Thermocouple loose. Replace.
Terminal wrongly positioned causing Tighten.
Installer to resite boiler.
Fit correctly.
Replace.
Re-tighten.
Refit.
GasRegion to adjust.
Clean pilot tube or replace pilot
injector.
Low flow rate pump duty not sufficient.
Water Filter blockad.
Low flow rate systemvery restrictive.
Low flow rate, air in system.
Water section spindle bent or dry.
Diaphragm split or stretched.
Thermostat not seatedproperly.
Gassupply insufficient.
Heat exchangerblocked.
Pump speedtoo slow.
Inspect clean.
Check working pressure8 in. w.g.
at servicetap.
Descaleor replace.
Adjust.
Flow and return pipes crossed or plaster,
cementin pipes. Rectify.
Installer to check pump data.
Clean.
Open systemby-pass.
Purgethoroughly, fit air separator
if persistentor wherconvectorsare
useda heademitters.
Replaceor grease.
Replace.
Re-circulation of flue products. Removeflue set and fit correctly.
Terminal badly sited and flue set wrongly
assembled Reflit .
Terminal not fitted in wall liner.
Over-gassed. Fit correctly.
Check sealingof blue. Adjust setto correct gasrate.
Re-sealfit correctly.
15

Imp. Chaffoteaux et Maury
FM. 92220-l 18 - 1182