Elson 120zi User manual

1
Pack Contents
Zircon unvented water heater incorporating immersion heater(s) & thermal controls•
Factoryttedtemperature/pressurereliefvalve(setat90°C/1Mpa(10bar))•
Coldwatercombinationvalveassembly•
Expansionvessel&mountingbracket•
Tundish•
2 Port motorised valve (indirect models only)•
Compressionnuts&olives•
Immersion heater spanner•
Installation & servicing instructions•
Guarantee card•
IMPORTANT
Pleaseread&understandalltheseinstructionsbeforecommencinginstallation.
Pleaseleavethismanualwiththecustomerforfuturereference.
Zircon Installation Manual
Unvented Direct & Indirect Water Heaters
Installation & Servicing Instructions

2
INTRODUCTION............................................................2
GENERALREQUIREMENTS........................................3
INSTALLATIONGENERAL............................................5
INSTALLATIONDISCHARGE........................................7
INSTALLATIONDIRECT...............................................11
INSTALLATIONINDIRECT...........................................12
COMMISSIONING.......................................................14
MAINTENANCE...........................................................15
USERINSTRUCTIONS...............................................16
FAULTFINDING&SERVICING..................................17
SPARES.......................................................................18
HEATLOSS.................................................................19
ENVIRONMENTALINFORMATION.............................19
COMMISSIONINGCHECKLIST.................................22
SERVICERECORD.....................................................23
GUARANTEE...............................................................24
TECHNICALSUPPORT...............................................24
CONTENTS
The cylinder is a purpose designed unvented water
heater.Theunithasastainlesssteelinnervessel,
whichensuresanexcellentstandardofcorrosion
resistance.Theoutercasingisacombinationof
resilient thermoplastic mouldings and plastic coated
corrosionproofedsteelsheet.Allproductsare
insulatedwithCFCfreepolyurethanefoamtogive
goodheatlossperformance.(seeTable6,page19)
The unit is supplied complete with all the necessary
safetyandcontroldevicesneededtoallow
connectiontothecoldwatermains.Allthese
componentsarepresetandnotadjustable.
Thisappliancecomplieswiththerequirementsofthe
CEmarkingdirectiveandisKiwaapprovedtoshow
compliancewithBuildingRegulations(SectionG3).
Thefollowinginstructionsareofferedasaguide
toinstallationwhichmustbecarriedoutbya
competentplumbingandelectricalinstallerin
accordancewithBuildingRegulationG3,The
BuildingStandards(Scotland)Regulations1990,or
TheBuildingRegulations(NorthernIreland).
NOTE:Priortoinstallationtheunitshouldbestored
inanuprightpositioninanareafreefromexcessive
damporhumidity.
THEBENCHMARKSCHEME
Benchmarkplacesresponsibilitiesonboth
manufacturersandinstallers.Thepurposeisto
ensure that customers are provided with the correct
equipmentfortheirneeds,thatitisinstalled,
commissioned and serviced in accordance with the
manufacturer’sinstructionsbycompetentpersons
andthatitmeetstherequirementsoftheappropriate
BuildingRegulations.TheBenchmarkChecklistcan
beusedtodemonstratecompliancewithBuilding
Regulationsandshouldbeprovidedtothecustomer
forfuturereference.
Installersarerequiredtocarryoutinstallation,
commissioningandservicingworkinaccordance
withtheBenchmarkCodeofPracticewhichis
availablefromtheHeatingandHotwaterIndustry
CouncilwhomanageandpromotetheScheme.Visit
www.centralheating.co.ukformoreinformation.
IMPORTANTNOTETOUSER:PLEASEREFERTO
THEUSERINSTRUCTIONSSECTIONONPAGE16
FORIMPORTANTINFORMATIONWITHRESPECTTO
THEBENCHMARKSCHEME
INTRODUCTION

3
IMPORTANT:
THISAPPLIANCEISNOTINTENDEDFORTHE
USEBYPERSONS(INCLUDINGCHILDREN)
WITHREDUCEDPHYSICAL,SENSORY
ORMENTALCAPABILITIES,ORLACKOF
KNOWLEDGEANDEXPERIENCE,UNLESS
THEYHAVEBEENGIVENSUPERVISIONOR
INSTRUCTIONCONCERNINGTHEUSEOFTHE
APPLIANCEBYAPERSONRESPONSIBLEFOR
THEIRSAFETY.
CHILDRENMUSTBESUPERVISEDTOENSURE
THEYDONOTPLAYWITHTHEAPPLIANCE.
SITINGTHEUNIT
Thecylindermustbeverticallyoormounted.
Althoughlocationisnotcritical,thefollowingpoints
shouldbeconsidered:
Thecylindershouldbesitedtoensureminimum•
deadlegdistances,particularlytothepointof
mostfrequentuse.
Avoid siting where extreme cold temperatures•
willbeexperienced.Allexposedpipework
shouldbeinsulated.
Thedischargepipeworkfromthesafetyvalves•
musthaveminimumfallof1:200fromtheunit
andterminateinasafeandvisibleposition.
Access to associated controls and immersion•
heatersmustbeavailabletoprovideforthe
servicingandmaintenanceofthesystem.
Wherethesecontrolsareinstalledagainstawalla
minimumdistanceof250mmmustbeleft(see
Fig.1).
Ensurethattheoorareaforthecylinderislevel•
andcapableofpermanentlysupportingthe
weightwhenfullofwater.(seeTable1)
WATERSUPPLY
Bear in mind that the mains water supply to the
propertywillbesupplyingboththehotandcold
waterrequirementssimultaneously.
It is recommended that the maximum water
demand is assessed and the water supply
checked to ensure this demand can be
satisfactorily met.
Note: A high mains water pressure will not
always guarantee high ow rates.
Whereverpossiblethemainssupplypipeshould
be22mm.Wesuggesttheminimumsupply
requirementsshouldbe0.15MPa(1.5bar)pressure
and20litresperminuteowrate.However,at
thesevaluesoutletowratesmaybepoorif
severaloutletsareusedsimultaneously.Thehigher
theavailablepressureandowratethebetterthe
systemperformance.
Thecylinderhasanoperatingpressureof0.35MPa
(3.5bar)whichiscontrolledbythecoldwater
combinationvalveassembly.Thecoldwater
combinationvalveassemblycanbeconnectedtoa
maximummainspressureof1.6MPa(16bar).
OUTLET/TERMINALFITTINGS(TAPS,ETC.)
Thecylindercanbeusedwithmosttypesofterminal
ttings.Itisadvantageousinmanymixershowers
tohavebalancedhotandcoldwatersupplies.In
theseinstancesabalancedpressurecoldwater
connectionshouldbeplacedbetweenthe2pieces
ofthecoldwatercombinationvalveassembly(see
Fig.2).Outletssituatedhigherthanthecylinderwill
giveoutletpressureslowerthanthatattheheater,a
10mheightdifferencewillresultina0.1MPa(1bar)
pressurereductionattheoutlet.Allttings,pipework
andconnectionsmusthavearatedpressureofat
least0.6MPa(6bar)at80°C.
GENERAL REQUIREMENTS
Table1:Unitweights
Fig.1:SitingtheUnit
WALL
Min 250mm Min 250mm
Type Model
Reference
Nominal
Capacity
(litres)
Weightof
unitfull
(Kg)
Weight
ofunit
(Kg)
Indirect 120zi 120 147 27
150zi 150 182 32
170zi 170 204 34
210zi 210 250 40
250zi 250 294 44
300zi 300 352 52
Direct 120zd 120 144 24
150zd 150 178 28
170zd 170 201 31
210zd 210 247 37
250zd 250 289 39
300zd 300 349 49

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LIMITATIONS
Thecylindershouldnotbeusedinassociationwith
anyofthefollowing:
Solidfuelboilersoranyotherboilerinwhichthe•
energyinputisnotundereffectivethermostatic
control,unlessadditionalandappropriatesafety
measuresareinstalled.
Ascendingspraytypebidetsoranyotherclass•
1backsyphonageriskrequiringthatatypeAair
gapbeemployed.
Steamheatingplantsunlessadditionaland•
appropriatesafetydevicesareinstalled.
Situationswheremaintenanceislikelytobe•
neglectedorsafetydevicestamperedwith.
Watersuppliesthathaveeitherinadequate•
pressureorwherethesupplymaybe
intermittent.
Situationswhereitisnotpossibletosafelypipe•
awayanydischargefromthesafetyvalves.
In areas where the water consistently contains a•
highproportionofsolids,e.g.suspendedmatter
thatcouldblockthestrainer,unlessadequate
ltrationcanbeensured.
In areas where the water supply contains•
chloridelevelsthatexceed250mg/l.
OPERATIONAL SUMMARY
Maximummainspressure  1.6MPa(16bar)
Operatingpressure   0.35MPa(3.5bar)
Maximumdesignpressure  0.6MPa(6bar)
Expansionvesselchargepressure 0.35MPa(3.5bar)
Expansionreliefvalvesetting 0.6MPa(6bar)
T&Preliefvalvesetting  90-95°C/1.0MPa(10bar)
Maximumprimarycircuitpressure 1.0MPa(10bar)
(indirect only)
Pressuredrop(Primarycoil)  0.02MPa(0.2bar)
Storagecapacity   seeTable1
Weightwhenfull   seeTable1
IndirectModelsinconformancewithBSEN12897:2006

5
PIPEFITTINGS
Allpipettingsaremadevia22mmcompression
ttingsdirectlytotheunit.Thettingsarethreaded
3/4”BSPmaleparallel,shouldthreadedpipe
connectionsberequired.
COLDFEED
A22mmcoldwatersupplyisrecommended,however,
ifa15mm(1/2”)supplyexists,whichprovidessufcient
ow,thismaybeused(althoughmoreownoise
maybeexperienced).
Astopcockorservicingvalveshouldbeincorporated
intothecoldwatersupplytoenablethecylinderand
itsassociatedcontrolstobeisolatedandserviced.
COLDWATERCOMBINATIONVALVEASSEMBLY
The2-piececoldwatercombinationvalveassembly
(seeFig.2)canbelocatedanywhereonthecold
water mains supply prior to the expansion vessel
(seeFig.6Page10)butthetwopiecesdonothave
tobeinstalledtogether.
The pressure reducing valve incorporates the
pressure reducer and strainer and the expansion valve
incorporatestheexpansionandcheckvalves.Ensure
that the valves are installed in the correct order
andorientation.Noothervalvesshouldbeplaced
betweentheexpansionvalveandthecylinder.A
connectioncanbemadebetweentheexpansionand
pressurereducingvalvestoprovideabalancedcold
waterconnection.Theexpansionvalveconnection
mustnotbeusedforanyotherpurpose.
DRAIN TAP
Asuitabledrainingtapshouldbeinstalledinthecold
watersupplytothecylinderbetweentheexpansion
valve(seeFig.6Page10)andtheheaterataslowa
levelaspossible.Itisrecommendedthattheoutlet
pointofthedrainpipeworkbeatleast1metrebelow
theleveloftheheater(thiscanbeachievedby
attachingahosetothedraintapoutletspigot).
EXPANSIONVESSEL
The expansion vessel accommodates expansion
thatresultsfromheatingthewaterinsidetheunit.
Theexpansionvesselispre-chargedat0.35MPa
(3.5bar).Theexpansionvesselmustbeconnected
betweentheexpansionvalveandthecylinder(see
Fig.6Page10).Thelocationoftheexpansion
vessel should allow access to recharge the pressure
asandwhennecessary,thiscanbedoneusing
anormalcarfootpump.Itisrecommendedthat
theexpansionvesselisadequatelysupported.An
expansionvesselwallmountingbracketissupplied
forthispurposeandshouldbetted.
SECONDARYCIRCULATION
Ifsecondarycirculationisrequireditisrecommended
thatitbeconnectedtothecylinderasshown (see
Fig.3page5)via a swept tee joint into the cold
feedtotheunit.Asweptteejointisavailableasan
accessory(ordercodeno.5133565).
Thesecondaryreturnpipeshouldbein15mmpipe
andincorporateacheckvalvetopreventbackow.
AsuitableWRASapprovedbronzecirculation
pumpwillberequired.Onlargesystems,dueto
theincreaseinsystemwatercontent,itmaybe
necessarytotanadditionalexpansionvesseltothe
secondarycircuit.Thisshouldbedoneifthecapacity
ofthesecondarycircuitexceeds10litres.
Pipe capacity (copper):
15mmO.D.=0.13l/m(10litres=77m)
22mmO.D.=0.38l/m(10litres=26m)
28mmO.D.=0.55l/m(10litres=18m)
NOTE:SecondarycirculationisNOTrecommendedfor
directelectricunits.
OUTLET
Thehotwateroutletisa22mmcompressiontting
locatedatthetopofthecylinder.Hotwaterdistribution
pipeworkshouldbe22mmpipewithshortrunsof
15mmpipetoterminalttingssuchassinksand
basins.Pipesizesmayvaryduetosystemdesign.
INSTALLATION GENERAL
Fig.2:Coldwatercombinationvalveassembly
Fig.3:Secondarycirculationconnection

6
315
A
354 - indirect
B
HOT OUTLET
T&P VALVE
COLD INLET
PRIMARY RETURN
PRIMARY FLOW
25°
45°
30°
45°
595
Ø550
306 - direct
Fig.4Generaldimensions
Notes:
1.IndirectcylinderstestedinconformancewithBSEN12897:2006
2.Heatuptimefromcoldthrough45°C,withaprimaryowrate15ltrs/minat80°C+/-2°C.
3.Directheatingtimesassumeuseoflowerelementonly,fromcold,through45°C.
Table 2: Dimensions and performance
Type Model
Reference
Dimensions (mm) Primary Flow
(ltrs/min@80°C
+/-2°C)
CoilRating
(kW)
Heat-upTime
(mins)
HotWater
Capacity(ltrs)
(volumeofwater
drawnoff>40°C)
A B
Indirect 120zi 930 615 15 12.5 29 104
150zi 1114 800 15 12.5 37 138.5
170zi 1240 925 15 15 35 156.5
210zi 1498 1184 15 15 43 196
250zi 1752 1378 15 18 43 227
300zi 2067 1693 15 19 49 242.5
Direct 120zd 930 615 121 104
150zd 1114 800 152 138.5
170zd 1240 925 173 156.5
210zd 1498 1184 215 196
250zd 1752 1378 257 227
300zd 2067 1693 310 242.5

7
DISCHARGEPIPEWORK
ItisarequirementofBuildingRegulationG3that
anydischargefromanunventedsystemisconveyed
towhereitisvisible,butwillnotcausedangerto
personsinoraboutthebuilding.Thetundishand
dischargepipesshouldbettedinaccordance
withtherequirementsandguidancenotesof
BuildingRegulationG3.TheG3Requirementsand
Guidancesection3.50-3.63arereproducedinthe
followingsectionsofthismanual.Fordischarge
pipearrangementsnotcoveredbyG3Guidance
adviceshouldbesoughtfromyourlocalBuilding
ControlOfcer.Anydischargepipeconnected
tothepressurereliefdevices(ExpansionValve
andTemperature/PressureReliefValve)mustbe
installed in a continuously downward direction and in
afrostfreeenvironment.
Watermaydripfromthedischargepipeofthe
pressurereliefdevice.Thispipemustbeleftopento
theatmosphere.Thepressurereliefdeviceistobe
operated regularly to remove lime deposits and to
verifythatitisnotblocked.
G3REQUIREMENT
“...there shall be precautions...to ensure that the
hot water discharged from safety devices is safely
conveyed to where it is visible but will not cause
danger to persons in or about the building.”
The following extract is taken from the latest G3
Regulations
Discharge pipes from safety devices
Discharge pipe D1
3.50 Each of the temperature relief valves or
combined temperature and pressure relief valves
specied in 3.13 or 3.17 should discharge either
directly or by way of a manifold via a short length of
metal pipe (D1) to a tundish.
3.51 The diameter of discharge pipe (D1) should
be not less than the nominal outlet size of the
temperature relief valve.
3.52 Where a manifold is used it should be sized to
accept and discharge the total discharge form the
discharge pipes connected to it.
3.53 Where valves other than the temperature
and pressure relief valve from a single unvented
hot water system discharge by way of the same
manifold that is used by the safety devices, the
manifold should be factory tted as part of the hot
water storage system unit or package.
Tundish
3.54 The tundish should be vertical, located in the
same space as the unvented hot water storage
system and be tted as close as possible to, and
lower than, the valve, with no more than 600mm of
pipe between the valve outlet and the tundish (see
Diagram 1).
Note: To comply with the Water Supply (Water
Fittings) Regulations, the tundish should incorporate
a suitable air gap.
3.55 Any discharge should be visible at the tundish.
In addition, where discharges from safety devices
may not be apparent, e.g. in dwellings occupied by
people with impaired vision or mobility, consideration
should be given to the installation of a suitable safety
device to warn when discharge takes place, e.g.
electronically operated.
Discharge pipe D2
3.56 The discharge pipe (D2) from the tundish
should:
(a) have a vertical section of pipe at least 300mm
long below the tundish before any elbows or bends
in the pipework (see Fig. 5); and
(b) be installed with a continuous fall thereafter of
at least 1 in 200.
3.57 The discharge pipe (D2) should be made of:
(a) metal; or
(b) other material that has been demonstrated to
be capable of safely withstanding temperatures of
the water discharged and is clearly and permanently
marked to identify the product and performance
standard (e.g. as specied in the relevant part of BS
7291).
3.58 The discharge pipe (D2) should be at least one
pipe size larger than the nominal outlet size of the
safety device unless its total equivalent hydraulic
resistance exceeds that of a straight pipe 9m long,
i.e. for discharge pipes between 9m and 18m the
equivalent resistance length should be at least two
sizes larger than the nominal outlet size of the safety
device; between 18 and 27m at least 3 sizes larger,
and so on; bends must be taken into account in
calculating the ow resistance. See Fig 1, Table 3
and the worked example.
Note: An alternative approach for sizing discharge
pipes would be to follow Annex D, section D.2 of
BS 6700:2006 Specication for design, installation,
testing and maintenance of services supplying
water for domestic use within buildings and their
curtilages.
3.59 Where a single common discharge pipe serves
more than one system, it should be at least one pipe
size larger than the largest individual discharge pipe
(D2) to be connected.
INSTALLATION DISCHARGE

8
3.60 The discharge pipe should not be connected to
a soil discharge stack unless it can be demonstrated
that the soil discharge stack is capable of safely
withstanding temperatures of the water discharged,
in which case, it should:
(a) contain a mechanical seal, not incorporating
a water trap, which allows water into the branch
pipe without allowing foul air from the drain to be
ventilated through the tundish;
(b) be a separate branch pipe with no sanitary
appliances connected to it;
(c) if plastic pipes are used as branch pipes
carrying discharge from a safety device they should
be either polybutalene (PB) to Class S of BS 7291-
2:2006 or cross linked polyethylene (PE-X) to Class
S of BS 7291-3:2006; and
(d) be continuously marked with a warning that no
sanitary appliances should be connected to the pipe.
Note:
1. Plastic pipes should be joined and assembled
with ttings appropriate to the circumstances in which
they are used as set out in BS EN ISO 1043-1.
2. Where pipes cannot be connected to the
stack it may be possible to route a dedicated pipe
alongside or in close proximity to the discharge stack.
Termination of discharge pipe
3.61 The discharge pipe (D2) from the tundish
should terminate in a safe place where there is no
risk to persons in the vicinity of the discharge.
3.62 Examples of acceptable discharge
arrangements are:
(a) to a trapped gully with the end of the pipe below
a xed grating and above the water seal;
(b) downward discharges at low level; i.e. up to
100mm above external surfaces such as car parks,
hard standings, grassed areas etc. are acceptable
providing that a wire cage or similar guard is
positioned to prevent contact, whilst maintaining
visibility; and
(c) discharges at high level: e.g. into a metal
hopper and metal downpipe with the end of the
discharge pipe clearly visible or onto a roof capable
of withstanding high temperature discharges of
water and 3m from any plastic guttering system that
would collect such discharges.
3.63 The discharge would consist of high
temperature water and steam. Asphalt, roong felt
and non-metallic rainwater goods may be damaged
by such discharges.
Worked example of discharge pipe sizing
Fig.5:showsaG1/2temperaturereliefvalvewitha
dischargepipe(D2)having4No.elbowsandlength
of7mfromthetundishtothepointofdischarge.
FromTable3:
Maximumresistanceallowedforastraightlengthof
22mmcopperdischargepipe(D2)fromaG1/2
temperaturereliefvalveis9.0m.
Subtracttheresistancefor4No.22mmelbowsat
0.8meach=3.2m
Thereforethepermittedlengthequatesto:5.8m
5.8mislessthantheactuallengthof7mtherefore
calculatethenextlargestsize.
Maximumresistanceallowedforastraightlength
of28mmpipe(D2)fromaG1/2temperaturerelief
valvesequatesto18m.
Subtracttheresistanceof4No.28mmelbowsat
1.0meach=4.0m
Thereforethemaximumpermittedlengthequatesto:
14m
Astheactuallengthis7m,a28mm(D2)copperpipe
willbesatisfactory.
WARNINGS:
Undernocircumstancesshouldthefactorytted•
temperature/pressurereliefvalveberemovedother
thanbyacompetentperson.Todosowillinvalidate
anyguaranteeorclaim.
Thecoldwatercombinationvalveassemblymust•
bettedonthemainswatersupplytothecylinder.
Nocontrolorsafetyvalvesshouldbetamperedwith•
orusedforanyotherpurpose.
Thedischargepipeshouldnotbeblockedorused•
foranyotherpurpose.
Thetundishshouldnotbelocatedadjacenttoany•
electricalcomponents.

9
Table3:Sizingofcopperdischargepipe(D2)forcommontemperaturereliefvalveoutletsizes
NOTE:Theabovetableisbasedoncoppertube.Plasticpipesmaybeofdifferentboreandresistance.Sizesand
maximumlengthsofplasticshouldbecalculatedusingdatapreparedforthetypeofpipebeingused.
VALVE OUTLET
SIZE
MINIMUM SIZE OF
DISCHARGE PIPE D1
MINIMUM SIZE OF
DISCHARGE PIPE D2
FROM TUNDISH
MAXIMUM RESISTANCE
ALLOWED, EXPRESSED
AS A LENGTH OF
STRAIGHT PIPE (I.E. NO
ELBOWS OR BENDS
RESISTANCE CREATED BY
EACH ELBOW OR BEND
G 1/2 15MM 22mm
28mm
35mm
UP TO 9M
UP TO 18M
UP TO 27M
0.8M
1.0M
1.4M
G 3/4 22MM 28mm
35mm
42mm
UP TO 9M
UP TO 18M
UP TO 27M
1.0M
1.4M
1.7M
G 1 28MM 35mm
42mm
54mm
UP TO 9M
UP TO 18M
UP TO 27M
1.4M
1.7M
2.3M
Fixed grating
Discharge below
fixed grating
(Building Regulation
G3 section 3.61 gives
alternative points
of discharge)
Trapped
gully
Discharge pipe (D2) from tundish,
with continuous fall. See Building
Regulation G3 section 3.56, Table 1
and worked example
300mm
minimum
600mm maximum
Metal discharge pipe (D1) from
Temperature relief valve to tundish
Tundish
Safety device
(e.g. Temperature
relief valve)
Fig.5:Typicaldischargepipearrangement(extractfromBuildingRegulationG3Guidancesection3.50)

10
Fig.6:Typicalinstallation-schematic
EXPANSION
VESSEL
T&P RELIEF
VALVE
TO HOT
OUTLETS
MAINS
WATER
SUPPLY
ISOLATING
VALVE (NOT
SUPPLIED)
TUNDISH
DISCHARGE
PIPE
DRAIN COCK
(NOT SUPPLIED)
PRIMARY
RETURN
PRIMARY
FLOW
ELEMENT /
CONTROLS
HOUSING
INLET SECONDARY RETURN
TAPPING (IF REQUIRED)
NOT SUPPLIED
COLD WATER
COMBINATION
VALVE
(2-PIECE)
BALANCED
COLD WATER
CONNECTION
(IF REQUIRED)

11
SAFETY
DISCONNECTFROMTHEMAINSELECTRICAL
SUPPLYBEFOREREMOVINGANYCOVERS.
Never attempt to replace the immersion heater(s)
other than with the recommended immersion
heater(s).
DO NOT BYPASSTHETHERMALCUT-OUT(S)
INANYCIRCUMSTANCES.Ensurethetwo
malespadeterminationsontheundersideofthe
combinedthermostatandthermalcut-outare
pushedrmlyontothecorrespondingterminations
ontheelementplateassembly.
Incaseofdifcultycontactservicesupport;contact
detailsavailableatthebackofthisbooklet.
ELECTRICALSUPPLY
Allelectricalwiringshouldbecarriedoutbya
competentelectricianandbeinaccordancewiththe
latestI.E.EWiringRegulations.
Each circuit must be protected by a suitable fuse
and double pole isolating switch with a contact
separation of at least 3mm in both poles.
Theimmersionheater(s)shouldbewiredin
accordancewithFig7.Theimmersionheaters
MUSTbeearthed.Thesupplycableshouldbe
1.5mm23coreHOFRsheathedandmustberouted
throughthecablegripprovidedwiththeoutersheath
ofthecablermlysecuredbytighteningthescrews
onthecablegrip.
DO NOT operate the immersion heaters until the
cylinder has been lled with water.
Ensurethethermostatandthermalcut-outsensing
bulbsarepushedfullyintothepocketsonthe
elementplateassembly.
PLUMBINGCONNECTIONS
Directcylindersrequirethefollowingpipework
connections.
Coldwatersupplytoandfrominletcontrols.•
Outlettohotwaterdrawoffpoints.•
Dischargepipeworkfromvalveoutletsto•
tundish.
INSTALLATION - DIRECT
Fig.7:Electricalconnections(directschematic)
NL
1.5mm² 3 Core
HOFR sheathed
cable

12
SAFETY
DISCONNECTFROMTHEMAINSELECTRICAL
SUPPLYBEFOREREMOVINGANYCOVERS.
Never attempt to replace the immersion heater(s)
other than with the recommended authorised
immersionheater(s).
DO NOT BYPASSTHETHERMALCUT-OUT(S)
INANYCIRCUMSTANCES.Ensurethetwo
malespadeterminationsontheundersideofthe
combinedthermostatandthermalcut-outare
pushedrmlyontothecorrespondingterminations
ontheelementplateassembly.
Incaseofdifcultycontactservicesupport;contact
detailsavailableatthebackofthisbooklet.
ELECTRICALSUPPLY
Allelectricalwiringshouldbecarriedoutbya
competentelectricianandbeinaccordancewiththe
latestI.E.EWiringRegulations.
Each circuit must be protected by a suitable fuse
and double pole isolating switch with a contact
separation of at least 3mm in both poles.
Theimmersionheater(s)shouldbewiredin
accordancewithFig8.Theimmersionheaters
MUSTbeearthed.Thesupplycableshouldbe
1.5mm2 3coreHOFRsheathedandmustberouted
throughthecablegripprovidedwiththeoutersheath
ofthecablermlysecuredbytighteningthescrews
onthecablegrip.
DO NOT operate the immersion heaters until the
cylinder has been lled with water.
Ensurethethermostatandthermalcut-outsensing
bulbsarepushedfullyintothepocketsontheelement
plateassembly.
PLUMBINGCONNECTIONS
Indirectcylindersrequirethefollowing
pipeworkconnections.
Coldwatersupplytoandfrominletcontrols.•
Outlettohotwaterdrawoffpoints.•
Dischargepipeworkfromvalveoutletsto•
tundish.
Connectiontotheprimarycircuit.•
Allconnectionsare22mmcompression.However,
3/4”BSPparallelthreadedttingscanbettedtothe
primarycoilconnectionsifrequired.
BOILERSELECTION
Theboilershouldhaveacontrolthermostatandnon
self-resettingthermalcut-outandbecompatiblewith
unventedstoragewaterheaters.
Whereuseofaboilerwithoutathermalcut-out
isunavoidablea“lowhead”openventedprimary
circuitshouldbeused.Thefeedandexpansion
cisternheadabovethecylindershouldnotexceed
2.5m.
PRIMARYCIRCUITCONTROL
The 2 port motorised valve supplied with the cylinder
MUSTbettedontheprimaryowtothecylinder
heat exchanger and wired in series with the indirect
controlthermostatandthermalcut-outttedtothe
unit.
Primary circulation to the cylinder heat exchanger
mustbepumped;gravitycirculationWILLNOT
WORK.
SPACEANDHEATINGSYSTEMSCONTROLS
The controls provided with the cylinder will ensure
thesafeoperationoftheunitwithinthecentral
heatingsystem.Othercontrolswillbenecessaryto
control the space heating requirements and times
thatthesystemisrequiredtofunction,seeFig.8
below.
Thecylinderiscompatiblewithmostheating
controls,examplesofelectricalcircuitsareshownin
Figs.9and10(Page13).However,othersystems
maybesuitable,refertothecontrolsmanufacturers’
instructions,suppliedwiththecontrolsselected,for
alternativesystemwiringschemes.
INSTALLATION - INDIRECT
LN
1 2 3
Element Connections
1.5mm² 3 Core
HOFR sheathed
cable
Indirect control
wiring
Fig.8:Electricalconnections(indirectschematic)

13
Fig.9:Schematicwiringdiagram-Basic2x2portvalvesystem
Fig.10:Schematicwiringdiagram-3portmidpositionvalvesystem.N.B.Mustbeusedinconjunctionwith2port
zonevalvesupplied

14
FILLINGTHEUNITWITHWATER
Ensurethatallttingsandimmersionheatersare
correctlyttedandtightened.Animmersionheaterkey
is provided to aid tightening the immersion heater(s)
Checkexpansionvesselpre-chargepressure•
Thevesselissuppliedprechargedto0.35MPa
(3.5bar)tomatchthecontrolpressureof
thepressurereducingvalve.Theprecharge
pressureischeckedusingacartyregaugeby
unscrewing the plastic cap opposite the water
connection.
Checkallconnectionsfortightnessincludingthe•
immersionheater(s).Animmersionheaterkey
spannerissuppliedforthispurpose.
EnsurethedraincockisCLOSED.•
Openahottapfurthestfromthecylinder.•
Openthemainsstopcocktolltheunit.When•
waterowsfromthetap,allowtorunforafew
minutestothoroughlyushthroughanyresidue,
dirtorswarf,thenclosethetap.
Open successive hot taps to purge the system•
ofair.
SYSTEMCHECKS
Checkallwaterconnectionsforleaksandrectify•
asnecessary.
Turnoffmainswatersupply.•
Removethepressurereducingvalveheadwork•
toaccessthestrainermesh,cleanandre-t.
Manuallyopen,forafewseconds,eachrelief•
valveinturn,checkingthatwaterisdischarged
andrunsfreelythroughthetundishandoutat
thedischargepoint.
Ensurethatthevalve(s)reseatsatisfactorily.•
DIRECTUNITS
Switchonelectricalsupplytotheimmersion
heater(s) and allow the cylinder to heat up to
normalworkingtemperature(60°Crecommended,
approximatelygraduation4onthethermostat).
Ifnecessarythetemperaturecanbeadjustedby
insertingaatbladedscrewdriverintheadjustment
knobontopoftheimmersionheaterthermostatand
rotating.Theadjustmentrange1to5represents
atemperaturerangeof12°Cto68°C.Check
theoperationofthermostat(s)andthatnowater
hasissuedfromtheexpansionreliefvalveor
temperature/pressurereliefvalveduringtheheating
cycle.
INDIRECTUNITS
Filltheindirect(primary)circuitfollowingtheboiler
manufacturer’scommissioninginstructions.Toensure
thecylinderprimaryheatexchangerislled,the2
portmotorisedvalve(supplied)shouldbemanually
openedbymovingtheleveronthemotorhousingto
theMANUALsetting.Whentheprimarycircuitisfull
returnthelevertotheAUTOMATICposition.
Switchontheboiler,ensuretheprogrammeris
settoDomesticHotWaterandallowthecylinder
toheatuptoanormalworkingtemperature(60oC
recommended,approximatelygraduation4onthe
thermostat).Ifnecessarythetemperaturecanbe
adjustedbyinsertingaatbladedscrewdriverin
theadjustmentknobandrotating.Theminimum
thermostatsettingis12°C.
Theadjustmentrange1to5representsa
temperaturerangeof12°Cto68°C.
Checktheoperationoftheindirectthermostatand
2 port motorised valve and that no water has issued
fromtheexpansionreliefvalveortemperature/
pressurereliefvalveduringtheheatingcycle.
BENCHMARKLOGBOOK
Oncompletionoftheinstallationandcommissioning
proceduresdetailedinthismanualtheBenchmark
“Installation,CommissioningandServiceRecordLog,
pages22and23shouldbecompletedandsignedoff
bythecompetentinstallerorcommissioningengineer
intherelevantsections.Thevarioussystemfeatures,
locationofsystemcontrols,userinstructionsand
whattodointheeventofasystemfailureshouldbe
explainedtothecustomer.Thecustomershouldthen
countersigntheBenchmarkTMcommissioningchecklist
(page22)toacceptcompletion.TheServiceRecord
shouldbelledinwhenanysubsequentserviceor
maintenanceoperationiscarriedoutontheproduct.
COMMISSIONING

15
MAINTENANCEREQUIREMENTS
Unvented hot water systems have a continuing
maintenancerequirementinordertoensuresafe
workingandoptimumperformance.Itisessential
thatthereliefvalve(s)areperiodicallyinspected
andmanuallyopenedtoensurenoblockagehas
occurredinthevalvesordischargepipework.
Similarlycleaningofthestrainerelementand
replacementoftheairintheexpansionvesselwill
helptopreventpossibleoperationalfaults.
Themaintenancechecksdescribedbelowshould
beperformedbyacompetentpersonona
regularbasis,e.g.annuallytocoincidewithboiler
maintenance.
Afteranymaintenance,pleasecompletetherelevant
ServiceIntervalRecordsectionoftheBenchmark
ChecklistonPage22ofthisdocument.
INSPECTION
Theimmersionheaterbosscanbeusedasan
accessforinspectingthecylinderinternally.
SAFETYVALVEOPERATION
Manuallyoperatethetemperature/pressurerelief
valveforafewseconds.Checkwaterisdischarged
andthatitowsfreelythroughthetundishand
dischargepipework.Checkvalvereseatscorrectly
whenreleased.NOTE:Waterdischargedmaybe
very hot!
RepeattheaboveprocedurefortheExpansion
ReliefValve.
STRAINER
Turnoffthecoldwatersupply,boilerandimmersion
heaters.Thelowesthotwatertapshouldthenbe
openedtode-pressurisethesystem.Removethe
pressure reducing cartridge to access the strainer
mesh.Washanyparticulatematterfromthestrainer
undercleanwater.Re-assembleensuringtheseal
iscorrectlytted.DONOTuseanyothertypeof
sealant.
DESCALINGIMMERSIONHEATER(S)
Beforeremovingtheimmersionheater(s)theunit
mustbedrained.Ensurethewater,electricalsupply
andboilerareOFFbeforedraining.Attacha
hosepipetothedraincockhavingsufcientlength
totakewatertoasuitabledischargepointbelowthe
leveloftheunit.Openahottapclosetotheunitand
opendraincocktodrainunit.
DIRECTUNITS
Switchonelectricalsupplytotheimmersion
heater(s)andallowtoheatuptonormalworking
temperature(60ºCrecommended,approximately
graduation4onthethermostat).Ifnecessarythe
temperaturecanbeadjustedbyinsertingaat
bladedscrewdriverintheadjustmentknobontopof
theimmersionheaterthermostatandrotating.
Theadjustmentrange1to5representsa
temperaturerangeof12°Cto68°C.Checkthe
operationofthermostat(s)andthatnowater
hasissuedfromtheexpansionreliefvalveor
temperature/pressurereliefvalveduringtheheating
cycle.
INDIRECTUNITS
Open the cover(s) to the immersion heater
housing(s)anddisconnectwiringfromimmersion
heater(s)thermostat(s).Removethermostatby
carefullypullingoutwards.Removethermostat
capillarysensorsfromthepocketsontheimmersion
heater.Unscrewimmersionheaterbacknut(s)and
removeimmersionheaterfromtheunit.Akey
spannerissuppliedwiththecylinderunitforeasy
removal/tighteningoftheimmersionheater(s).Over
timetheimmersionheatergasketmaybecomestuck
tothematingsurface.Tobreakthesealinserta
roundbladedscrewdriverintooneofthepocketson
theimmersionheaterandgentlyleverupanddown.
Carefullyremoveanyscalefromthesurfaceofthe
element(s).DONOTuseasharpimplementas
damagetotheelementsurfacecouldbecaused.
Ensuresealingsurfacesarecleanandsealsare
undamaged,ifindoubttanewgasket
(partnumber95611822).
Replace immersion heater(s) ensuring the lower
(right angled) element hangs vertically downwards
towardsthebaseoftheunit.Itmaybehelpfulto
supporttheimmersionheaterusingaroundbladed
screwdriverinsertedintooneofthethermostat
pocketswhilstthebacknutistightened.Replace
thermostatcapillariesintopocket.Replacethe
immersionheaterthermostatbycarefullyplugging
the two male spade terminations on the underside
ofthethermostatheadintothecorresponding
terminationsontheelement.Rewire,check,close
andsecureimmersionheaterhousingcover(s).
EXPANSIONVESSELCHARGEPRESSURE
Removethedustcapontopofthevessel.Check
the charge pressure using a tyre pressuregauge.
Thepressure(withsystemde-pressurised)should
be0.35MPa(3.5bar).Ifitislowerthantherequired
settingitshouldbere-chargedusingatyrepump
(Schradervalvetype).DONOTOVER-CHARGE.
Re-checkthepressureandwhencorrectreplacethe
dustcap.
RE-COMMISSIONING
Checkallelectricalandplumbingconnectionsare
secure.Closethedraincock.Withahottapopen,
turn on the cold water supply and allow unit to
rell.DONOTswitchontheimmersionheater(s)
orboileruntiltheunitisfull.Whenwaterows
fromthehottapallowtoowforashortwhileto
purgeairandushthroughanydisturbedparticles.
Closehottapandthenopensuccessivehottapsin
systemtopurgeanyair.Whencompletelyfulland
purgedchecksystemforleaks.Theheatingsource
(immersionheater(s)orboiler)canthenbeswitched
on.
MAINTENANCE

16
WARNINGS
IFWATERDISCHARGESFROMTHE
TEMPERATURE/PRESSURERELIEFVALVEON
CYLINDERSHUTDOWNTHEBOILER.DONOT
TURNOFFANYWATERSUPPLY.CONTACT
ACOMPETENTINSTALLERFORUNVENTED
WATERHEATERSTOCHECKTHESYSTEM.
DONOTTAMPERWITHANYOFTHESAFETY
VALVESFITTEDTOTHESYSTEM.IFAFAULT
ISSUSPECTEDCONTACTACOMPETENT
INSTALLER.
BENCHMARK
ThecylinderiscoveredbytheBenchmarkScheme
whichaimstoimprovethestandardsofinstallation
andcommissioningofdomesticheatingand
hotwatersystemsintheUKandtoencourage
regularservicingtooptimisesafety,efciencyand
performance.
Benchmarkismanagedandpromotedbythe
HeatingandHotwaterIndustryCouncil.Formore
informationvisitwww.centralheating.co.uk.
Pleaseensurethattheinstallerhasfullycompleted
theBenchmarkChecklist(Page22&23)ofthis
manual and that you have signed it to say that
youhavereceivedafullandclearexplanationof
itsoperation.Theinstallerislegallyrequiredto
completeacommissioningchecklistasameansof
complying with the appropriate Building Regulations
(England&Wales).
AllinstallationsmustbenotiedtoLocalArea
BuildingControleitherdirectlyorthrougha
CompetentPersonsScheme.ABuildingRegulations
ComplianceCerticatewillthenbeissuedtothe
customerwhoshould,onreceipt,writethe
NoticationNumberontheBenchmarkChecklist.
Thisproductshouldbeservicedregularlytooptimise
itssafety,efciencyandperformance.Theservice
engineershouldcompletetherelevantService
RecordontheBenchmarkChecklistaftereach
service.
TheBenchmarkChecklistmayberequiredinthe
eventofanywarrantyworkandassupporting
documentation relating to home improvements
intheoptionaldocumentssectionoftheHome
ImprovementsPack.
FLOWPERFORMANCE
Wheninitiallyopeninghotoutletsasmallsurgein
owmaybenoticedaspressuresstabilise.Thisis
quitenormalwithunventedsystems.Insomeareas
cloudinessmaybenoticedinthehotwater.Thisis
duetoaerationofthewater,isquitenormalandwill
quicklyclear.
TEMPERATURECONTROLS–DIRECTUNITS
IMMERSIONHEATER(S)
Acombinedadjustablethermostatandthermal
cut-outisprovidedforeachimmersionheater.The
thermostatisfactorysettogiveawaterstorage
temperatureofapprox.55°Cto60°C.Accesstothe
thermostatcanbemadebyopeningtheimmersion
heatercover-DISCONNECTTHEELECTRICAL
SUPPLYBEFOREOPENINGTHECOVER(S).
Temperatureadjustmentismadebyinsertingaat
bladedscrewdriverintheslotontheadjustment
discontopofthethermostatandrotating.The
adjustmentrange1to5representsatemperature
rangeof12°Cto68°C(60°Cwillbeapproximately
position4).Ifinanydoubtcontactacompetent
electrician.
DONOTbypassthethermalcut-out(s)inany
circumstances.
TEMPERATURECONTROLS-INDIRECTUNITS
Thecylinderunitsarettedwithanindirect
thermostatandthermalcut-out.Thesecontrolsmust
bewiredinserieswiththe2portmotorisedzone
valvesuppliedtointerrupttheowofprimarywater
around the heat exchanger coil when the control
temperaturehasbeenreached.Thecontrolsare
located within the lower terminal housing along with
theimmersionheaterthermostat.Thethermostat
isfactorysettogiveawaterstoragetemperature
ofapprox.55°Cto60°C.Accesstothethermostat
canbemadebyopeningtheterminalhousing
cover-DISCONNECTTHEELECTRICALSUPPLY
BEFOREOPENINGTHECOVER.Temperature
adjustmentismadebyinsertingaatbladed
screwdriverintheadjustmentknobandrotating.The
minimumthermostatsettingis12°C.Theadjustment
range1to5representsatemperaturerangeof12°C
to68°C(60°Cwillbeapproximatelyposition4).Ifin
anydoubtcontactacompetentelectrician.
Animmersionheaterisalsoprovidedforuseshould
theindirectheatsourcebeshutdownforanypurpose.
The immersion heater control temperature is set
usingtheimmersionheaterthermostat.
DONOTbypassthethermalcut-out(s)inany
circumstances.
OPERATIONALFAULTS
Operationalfaultsandtheirpossiblecausesare
detailedintheFaultFindingsectionofthisbook.It
isrecommendedthatfaultsshouldbecheckedbya
competentinstaller.
The air volume within the expansion vessel will
periodically require recharging to ensure expanded
waterisaccommodatedwithintheunit.Adischarge
ofwaterINTERMITTENTLYfromtheexpansion
valve will indicate the air volume has reduced to
a point where it can no longer accommodate the
expansion.
USER INSTRUCTIONS

17
IMPORTANT
Afterservicing,completetherelevantService•
IntervalRecordsectionoftheBenchmark
Checklistlocatedonpage22and23ofthis
document.
Servicingshouldonlybecarriedoutby•
competent persons in the installation and
maintenanceofunventedwaterheating
systems.
AnysparepartsusedMUSTbeauthorised•
parts.
Disconnecttheelectricalsupplybeforeremoving•
anyelectricalequipmentcovers.
NEVERbypassanythermalcontrolsoroperate•
systemwithoutthenecessarysafetyvalves.
Watercontainedinthecylindermaybevery•
hot,especiallyfollowingathermalcontrolfailure.
Cautionmustbetakenwhendrawingwaterfrom
theunit.
SPAREPARTS
Afullrangeofsparepartsareavailableforthe
cylinderrange(Table5Page18).Refertothe
technicaldatalabelontheunittoidentifythemodel
installedandensurethecorrectpartisordered.You
willneedtoquotetheserialnumber,whichisprinted
onthedatalabel.
FAULT FINDING
Thefaultndingchart(Table4Page17)willenable
operational faults to be identied and their possible
causesrectied.Anyworkcarriedoutonthecylinder
unvented water heater and its associated controls
MUST be carried out by a competent installer for
unvented water heating systems. In case of doubt
contact servicesupport(seecontactdetailsonback
page).
WARNING
DO NOT TAMPER WITH ANY OF THE SAFETY VALVES
OR CONTROLS SUPPLIED WITH THE CYLINDER AS
THIS WILL INVALIDATE ANY GUARANTEE.
FAULT FINDING & SERVICING
Table4:FaultFindingChart
Fault Possible Cause Remedy
Nohotwaterow
Mainssupplyoff Checkandopenstopcock
Strainerblocked Turnoffwatersupply.Removestrainerand
clean
Coldwatercombinationvalveincorrectly
tted
Checkandretasrequired
Waterfromhottap
is cold
Direct immersion heater not switched on Checkandswitchon
Directimmersionheaterthermalcut-out
has operated
Check,resetbypushingbuttononthermostat
Indirect programmer set to central heat-
ing only
Check,settodomestichotwaterprogramme
Indirectboilernotworking Checkboileroperation.Iffaultissuspected
consultboilermanufacturer’sinstructions
Indirectthermalcut-outhasoperated Check,resetbypushingbuttononthermostat
Checkoperationofindirectthermostat
Indirect motorised valve not connected
correctly
Checkwiringand/orplumbingconnectionsto
motorised valve
Waterdischarges
fromexpansion
valve
INTERMITTENTLY
Expansion vessel charge pressure has
reducedbelow3.5bar,orsettohigh
SeeMaintenancesectionforre-chargingof
expansion vessel procedure
CONTINUALLY
coldwatercombinationvalvepressure
reducernotworkingcorrectly.
Expansion valve seat damaged
Checkpressurefromcoldwatercombination
valve.Ifgreaterthan3.5barreplacepressure
reducing valve
Removeexpansionvalvecartridge,check
conditionofseat.Ifnecessarytnewexpansion
valve
Waterdischarges
fromT&Prelief
valve
Thermalcontrolfailure
NOTE: water will be very hot
Switchoffpowertoimmersionheater(s)and
shutdownboiler.
DO NOTturnoffwatersupply.Whendischarge
stopscheckallthermalcontrols,replaceiffaulty
Milkywater
Oxygenated water Waterfromapressurisedsystemreleases
oxygenbubbleswhenowing.Themilkinesswill
disappearafterashortwhile

18
SPARES
Table5:Spares
Fig.11:IndirectCylinderSparesDiagram
14 9 12
625 13
5 1 6 13
9 12
14
4 6 13
5 1 6 13
9 8 11
Item
Number
Description PartNumber
1 Immersion heater (Bent) 95606984
2Immersionheater(Straight) 95606986
3 Solarpocketplateassembly 95607064
4 Blankingplateassembly 95605881
5 Immersionheatergasket 95611822
6 Immersionheaterbacknut 95607869
7 Immersionheaterkey
spanner
95607861
8Indirect thermostat &
thermalcut-out
95612716
9Direct thermostat & thermal
cut-out
95612717
10 Solarthermalcut-out 95612698
11 6Wayterminalblock 95607933
12 3Wayterminalblock 95607932
13 Terminal cover 95614095
14 Temperature/Pressure
reliefvalve
95605810
15 Tundish 95605838
16 Expansionvalve-complete
-0.6MPa(6Bar)
95607030
17 Coldwatercombination
valve-complete
95605047
18 Motorised2portvalve 95605049
19 AccessoryKit-Indirect
(without expansion vessel)
95607968
20 AccessoryKit-Direct
(without expansion vessel)
95607969
21 Expansionvessel-12litre
(120&150litremodels)
95607863
22 Expansionvessel-18litre
(170&210litremodels)
95607864
23 Expansionvessel-24litre
(250&300litremodels)
95607612
Fig.12:DirectCylinderSparesDiagram

19
Table6:Standingheatlosses(basedonanambientair
temperatureof20°Candastoredwatertemperatureof
65°C)
Productsaremanufacturedfrommanyrecyclable
materials.Attheendoftheirusefullifetheyshouldbe
disposedofataLocalAuthorityRecyclingCentrein
ordertorealisethefullenvironmentalbenets.
InsulationisbymeansofanapprovedCFC/HCFCfree
polyurethanefoamwithanozonedepletionfactorof
zero.
HEAT LOSS ENVIRONMENTAL
Nominal
Capacity
(Litres)
StandingHeatLoss
per day
(kWh/24h)
per year
(kWh/365d)
120 1.47 537
150 1.70 621
170 1.92 701
210 2.10 767
250 2.22 811
300 2.52 920

20
NOTES