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TECHniCAl BUllET in nUMBEr 281

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Inland Waterways Boat Findings

Inland Waterways Boat Findings

Listed below are the main reasons found for premature failure of diesel heaters on inland waterway boats.

These are listed in order of importance:

1. Poor installation.

2. Operator error.

3. Poor fuel / fuel system.

4. Poor voltage.

1. Main Problems with Installation

a) Poor plumbing on the water and fuel systems.

b) Heaterfittedinengineroomandrunningtoohot(poorengineroomventilation).

c) Incorrectheaterspecificationi.e.Fittinga10kWwhena5kWwouldbesufficient.

2. Main Problems with Operator Error

a) Shutting all the radiators down at night except the one in the bedroom.

b) Not servicing the heater on a regular basis.

c) Using the heater for hot water only without a secondary circuit i.e. Towel rail, etc.

d) Using the heater as a frost watch heater.

3. Main Problems with Fuel

a) Bad quality red diesel from the pump.

b) Fueldegradinginthetankovertime(Cetanedropping).

c) Fuelbug.

d) Standpipefittedlowerthantheenginepickupinthetank.

4. Main Problems with Voltage

a) Short cycling running the battery down.

b) Powercable’soutofspecification(toothin).

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Inland Waterways Boat Findings

Main Problems with Installations, Operator Error, Fuel and Voltage in More Detail

Water Plumbing

Shortcyclingaroundthecalorifierloop(see Figure 1).

Onmostinlandwaterwayboats,thefirstpartintheplumbingsystemisthecalorifier.

Thiscanmakeashortcircuitbetweenthemainflowandreturnpipes.

Itisextremelyimportantthatthispartofthesystemisbalancedproperly,iftoomuchwaterisallowedtoflowthroughthis circuit the heater will detect that the system is up to temperature and start to shut down.

As the heater shuts down it will detect the cooler water returning from the radiator circuit and start up again.

Whenthishappensonaregularbasistheheaterwillsufferforthefollowingreasons.

1. Stoppingandstartingtheheaterdoesnotallowtheburnerchambertoheatupsufficientlytoburnoutany carbon produced during start up.

2. Stoppingandstartingtheheaterbringstheglowpininonbothoccasionsusing10Ampseachtime,thiscan achieve a low voltage problem within a relatively short period of time.

3. Ifthesystemisuptotemperatureandtheheaterisfiringupandshuttingdownwhenhot,thecoolingeffectofthecombustionaircanbeeffected.Thiscausesthelatentheatbuilduptotravelbackfromtheburner chamber and dry out the front combustion air blower bearing. It may also lead to over heating of theICU.

Figure 1

Heater 18mm Hose 22mm Pipe

22 X 15 X 22mmTee

22 X 15 X 22mmTee

22 X 15 X 22mmTee

22 X 15 X 22mmTee

22 X 15 X 22mmTee

22 X 15 X 22mmTee

22 X 15 X 22mmTee

22mm Pipe22mm Pipe

22mm Pipe

22mm Pipe

15m

m P

ipe

15m

m P

ipe

15m

m P

ipe

15m

m P

ipe

15m

m P

ipe

Optional Close Off Service Valves

FLOW

22mm Pipe

Optional Summer Close Off Valves

Calorifier

Twin port header tank acts as an auto bleed sytem,Mixes antifreeze and adds a body of coolant to evenout heater run time.

Calorifier loop causingshort cycling

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Inland Waterways Boat Findings

Rectification

Asimple,cheap,tamperproofregulatingvalvefittedintothecalorifierloop(see Figure 2).

Oncethevalveisfittedthesystemshouldbebalancedasfollows.Ideallythisshouldbedonewhenthesystemiscold.

Shuttheregulatingvalveinthecalorifierfeedpipe,starttheheater.

Whentheradiatorloopbecomeshotslowlyopentheregulatingvalveforthecalorifierkeepingonehandonthereturnpipe, the pipe should remain warm.

Ifthereturnpipeishot,toomuchwaterisflowingthroughthecalorifierandtheheaterwillshortcycle.

Ifthereturnpipeiscold,notenoughwaterisflowingthroughthecalorifierandthedomesticwaterwilltaketolongtoheat up.

If the heater is to be used for hot water only and all the radiators have been shut down a secondary water circuit must befitted.NotethetowelrailcircuitinFig2hasnovalves.

Note: IfasystemisalreadyfittedwithavalveinthecalorifiercircuitDON’Ttakeitforgrantedthatthesystemisbalanced,pleasecheckit.

Attention: Ifthesystemhassummervalvesfittedwithnobypassloop,removethevalvesandmakesureenough water can still circulate around the system without causing the heater to overheat. The radiators can be shut down instead of using the summer valves.

Check the main flow and return pipes are 22mm.

Figure 2

Heater 18mm Hose 22mm Pipe

22 X 15 X 22mmTee

22 X 15 X 22mmTee

22 X 15 X 22mmTee

22 X 15 X 22mmTee

22 X 15 X 22mmTee

22 X 15 X 22mmTee

22 X 15 X 22mmTee

22mm Pipe22mm Pipe

22mm Pipe

22mm Pipe

15m

m P

ipe

15m

m P

ipe

15mm Regulator Valve

15m

m P

ipe

15m

m P

ipe

15m

m P

ipe

Optional Close Off Service Valves

FLOW

22mm Pipe

Optional Summer Close Off Valves

Calorifier

Regulator Valve

Twin port header tank acts as an auto bleed sytem,Mixes antifreeze and adds a body of coolant to evenout heater run time.

6

Inland Waterways Boat Findings

Fuel Supply Plumbing

ItisextremelycommononinlandwaterwayboatstofindthattheenginefuellinehasbeentappedintotofeedtheEberspacherheater.Thisisgenerallythecasewhenthetopofthetankisnotaccessible.

ANarrowboatstandpipekit(PartNo.29.2199.01.7785)shouldbefitted.

Alargediameterfuelstandpipe(i.e.12–15mm)orfuelsystemcancausetwoproblems.

1. Itwillalterthefinelycalibratedfuellingbeingdeliveredtotheheaterduetothefuelmeteringpumphavingtofightagainsttheweightoffuelinthepipes.

This in turn will cause a poor burn and premature carbon build up.

2. In some cases the weight of fuel hanging in the stand pipe can overcome the one way ball valve in the fuelmeteringpumpandoveraperiodoftimethefuelwillstarttosiphonbacktothetank.Thiswillcausetheheatertotakeoneortwoattemptstostart.

Itisalsoacommonproblemthatalargeenginetypefuelfilter/watertraphasbeenfittedintotheheatersfuelline.

Theconsequenceoffittingafilter/watertrapisdamagetothefuelpumpsplungerduetoexcessivelylongfuelprimingtimes(itcantakeover50startattemptstoprimetheaverageenginefuelfilter)duringthistimethepumpisrunningwithoutsufficientlubrication.Thiscanaffectpumpcalibration.

Withboththesecasestheheatermaystartandappeartorunfine,butusuallywithin6to12monthsprematurefailure will result due to carbon build up caused by incorrect fuelling.

If the fuel metering pumps plunger has been severely damaged by running ‘dry’ the fuel metering pump may fail totally.

ThecorrectspecificationfuelsystemandstandpipeMUSTbefitted.

The Engine Room

Inlandboats(NarrowboatsandWidebeams)tendtohaveverypoorventilationintotheenginebay,thiscanleadtorelativelyhighengineroomtemperaturesinexcessof60°C.Themaximumcombustionairintaketemperaturefortheheateris25°C.

It is extremely IMPORTANT that this temperature is not exceeded.

The effects of hot combustion air are extremely detrimental to the heater in 2 ways:

1. The air/fuel ratio will change, the burn becomes dirty and will produce excessive carbon.

2. The combustion air helps cool the internal components that are situated directly behind the combustion chamber.ThisistheblowermotorandtheICU.

If these components become excessively hot they will fail prematurely.

Rectification

Drawthecombustionairfromoutsidetheengineroomoratworstdirectlyfromtheengineroomvent.(Combustionairshouldnotbetakenfromanylivingarea)

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Inland Waterways Boat Findings

Wrong Heater Specified

Thisisafairlycommonproblem,buildersandcustomerswillspecifyabigheaterbecausetheythinkitwillworklessandheatupquicker.Infacttheoppositeistruetheheaterwill‘shortcycle’orspendmostofitstimeontickover.Theboatwillonlyheatupasquickastheheatbeinggivenoffbytheradiators.

Iftheheatersitsontickoverforprolongedperiodsoftimeitwillnotburnoutthecarbonproducedduringthiscycle.

Example: A70ftNarrowboatwillhaveaheatlossofapproximately3kWwhentheambientairtemperatureis0°C.Theaveragetotalcombinedradiatoroutputofthistypeofboatis2.5kWto3.5kW

Youwillseefromthefiguresabovethatifthemaximumheatthatcanbeextractedis3.5kWplusforexample1.5kWforacoldcalorifier,fittinga10kWheaterwillhavenobenefittotheboatandadetrimentaleffectontheheater.

Operator Error

Thisisverycommonaspeopleexpecttouseadieselfiredheaterinexactlythesamewayastheyusetheirgasboilerathome.Thisisnotthecase,howeverwithalittleeducationitcanberunefficientlyinasimilarway.

Using the heater for hot water only will again cause the heater to ‘short cycle’ if the heater is left on once the water isuptotemperature.Eachtimeasmallamountofwaterisremovedfromthetanktheheaterwilltryandreplacethatlostheat.With10,5oreven4kW’sagaintheheaterwillstartupandshutdownalmostimmediately‘shortcycle’.

Iftheownerswitchestheheateronuntilthetankishot,thenswitchestheheateroffuntilthehotwaterhasbeenused, next time the heater is run it will run for longer thus burning more carbon from the burner chamber.

Ifaflowandreturnplumbingsystemhasbeenused,theremustbeatleastonepipecircuitthatcannotbeclosed.Ideally this will be a towel rail or small radiator in the bathroom. This will act as a bypass if all the radiators are shut down or closed off for summertime use (see Figure 2).

Usingtheheaterasafrostwatchheaterisnotadvisable.Ifitmustbedone,keeptheradiatorsturnedupsotheheaterrunsinitshighheatmode,ratherthanstartingupandrunninginlowheat,i.e.tickingover.

Switchoperation.Thisisacommonproblemonhirefleets,peoplewillswitchtheheateron,becausetheycannothearanythingtheyswitchtheheaterbackoffbeforeithasstarted,thenswitchbackonastheheateristryingtogointo cool down cycle, so of course it will not start again.

Wehaveproducedalabelthatcanbefittedbytheswitchifyoususpectthisscenarioishappening. LabelPartNumber17946.

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Inland Waterways Boat Findings

Fuel

“Reddiesel”ontheinlandwaterwaysisnowultra-lowsulphurgasoil,afuelusedspecificallyfor‘offroadmachinery,agriculturalequipmentandinlandwaterways.ThisfuelcancontainalowpercentageofFAME(FattyAcidMethylEster)commonlyknownasbiofuel.

Although this fuel is generally far better quality than the previous high sulphur gas oils that were used it still needs to belookedafterandkeptcleanandfresh.

Fuelconditionisextremelyimportanttoadieselfiredheater.Example:Ifaheaterissufferingfromoneoftheproblems we have just covered, the carbon build up can be accelerated by the condition of the fuel.

Degradation:Gasoilwillstarttodegradeafterapproximately6monthsthisiswheretheoxidationinthefuelcausesheavymoleculestoseparateinthefuelandbegintosinktothebottomofthetankforming‘sludge’andvarnishes.Waterwillalsostarttoseparatefromthefuelandcollectwiththewatergeneratedbycondensation.Thecetanevalueofthefuelwillbegindropping.Thisprocessstartstohappenbeforethefuelevenleavestherefinery.FuelisgenerallyrefinedabroadandthentransportedbytankershiptotheUKwhereitsitsinthemainstoragedepotstankuntilitistransportedbyroadtankertothesmallerdistributiondepots,fromhereitistransportedtothemarinasfueltank,thenfinallyintotheboatstank.Thatisnormallythelasttimethatthefuelwillgetmixedorshakenbecauseunlikeseaboatsorroadvehicles,theinlandwaterwaystendtobecalmsothefuelisallowedtositandseparate.

Eventually there will come a point when the cetane value of the fuel falls so low the fuel will no longer ignite in the heater.DONOTtakefuelforgrantedoroverlookitwhenfaultfindingtheheater.Ifafueladditivehasbeenaddedmakesureitismixedinandnotjusttippedintoatankandallowedtositthere.

Dieselbugwillcauseproblemswithaheater.Itwillnormallybefoundasablacksludgeinthepumpfilter.Thiswillalterthefuellingattheheaterbyrestrictingthefuelfilter,ultimatelytothepointwheretheheaterwillnolongerrun.Ifadditiveshavebeenaddedcheckthefuelhasbeenagitatedregularly.Somefueladditiveswillseparateoutifthefuelisnotstirredorshakenupregularly.

Tip: Iftheheatersstandpipeiskeptatleast25mmshorterthantheenginespickupitwillstandabetterchance of pulling slightly cleaner fuel. Also if the heater has used the last of the fuel it can reach, there willstillbeenoughleftinthetanktoruntheengine.

Ifitiswintertime,checkthatfuelhasbeenwinterisedtostopwaxingatlowtemperatures.Gasoilwillnotbeautomaticallywinterisedatthepumpsandwillstartwaxingfrom0°C.

Runtheheateratleastonceamonthfor15–20minutestokeepfuelfreshinthelines,copperfuellinesoxidizeanddestroy diesel.

Rectification

Goodhousekeepingisoneofthemainpoints,keepfueltankscleanandkeepfuelingoodcondition.

Useallthefuelinthetankandreplacewithfreshasoftenaspossible.

Fueladditiveswithstabilizersandanti-oxidantswillhelpslowdownthedegradationprocess.

9

Inland Waterways Boat Findings

Voltage

Voltage problems are common on inland boats for several reasons.

1. Each time the heater starts the glow pin or glow plug depending on the heater comes into circuit. Between10Ampsand22Ampsaretakenfromthebattery,thisalsohappenswhentheheatershutsdownastheglowpin/plugcomesbackintocircuitforselfcleaning.

If this is happening on a regular basis, i.e. Short cycling of the heater, the battery can be drained in a relatively short period of time.

2. Powercablesaretoothin.Theseshouldbekeptwithinthemanualsspecification.

3. Flatbatteries,ownerscaneasilyunderestimatetheamountoftimeittakestorechargealargebankofbatteries.

4. Loose connections or fuses.

5. Corrosionorverdigrisbuilduponconnectionsorfuses.

Rectification

Againgoodhousekeeping,lookingafterthebatteries,checkingterminalsetc.

Tip: VoltageshouldbecheckedatthebatteriesANDattheheaterastheheaterisstartingupandtheglowpin/plugisincircuit.Withthesystemunderloadanyfaultswillbeeasiertospot.

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Inland Waterways Boat Findings

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eberspächer (uk) Ltd

Climate House

Yeoman road, ringwood

Hampshire BH24 3fA

Tel: 01425 480151

fax: 01425 480152

enquiries@eberspaecher.com

www.eberspacher.com