Onan NH User manual

•i1.''
OPERATOR'S MANUAL
AND
PARTSCATALOG
FOR
NH
SERIES
ELECTRIC GENERATING SETS
ft
940-0301
4AF74
PrintedInU.S.A.

INTRODUCTION
THIS OPERATOR'S MANUALCONTAINSINFORMATION
PERTAINING TOTHEINSTALLATION,OPERATION,AND
MAINTENANCEOFYOURONANUNIT.A PARTS CATALOG
IS ALSO INCLUDEDINTHISMANUAL.
WE SUGGEST THATTHISMANUALANDTHEWIRING
DIAGRAMWHICHACCOMPANIES EVERY ONAN UNIT BE
RETAINED AND REFERRED TOWHENMAKINGEQUIP-
MENT ADJUSTMENTS OR ORDERING PARTS. ADDITIONAL
COPIES ARE AVAILABLE FORA NOMINAL CHARGE FROM
YOUR ONANDISTRIBUTOR.
I,'
WHENORDERING PARTS REMEMBERTOINCLUDETHE
ONANMODEL,SPECIFICATION LETTER, AND SERIAL
NUMBER LOCATED ONTHENAMEPLATEOFYOURONAN
UNIT.THISIS ESSENTIAL TO ENSURE THE CORRECT PART
IS SHIPPEDTOYOU.
FOR MAJOR REPAIR SERVICE, CONTACTYOURONAN
AUTHORIZED DISTRIBUTOR.
WARNING
]
ONAN RECOMMENDS THAT ALL SERVICE INCLUDING
INSTALLATION OF REPLACEMENT PARTS BE DONE BY
QUALIFIED ELECTRICAL AND/OR MECHANICAL SER-
VICEMEN. FROM THE STANDPOINT OF POSSIBLE INJURY
AND/OR EQUIPMENT DAMAGE IT IS IMPERA TIVE THA T
THE SERVICEMAN IS QUALIFIED.

GENERAL INFORMATION
Thismanualcontainsinstallationandoperationin-
structionsaswellasinformationrequiredforproper
maintenance,adjustmentandrepairoftheNH
generatingset.Becausethefirstandmostimportant
partofrepairworkisthecorrectdiagnosisofthe
trouble,thismanualincludes a troubleshootingchart.
Studyandfollowtheinstructionscarefully.Proper
serviceandmaintenancewillresultinlongerunitlife
andbetterperformance.
HowtointerpretMODELandSPECNO.
6.5NH- SCR/IF
1. 2 45
1. Kilowattratingoftheunit.'
2. FactorycodeforSERIESidentification.
3.Combineswithnumber 1 and2 toidentifymodel.
Indicatesmodel,outputvoltage,methodofstar-
ting:
E- ELECTRICstarting;R - REMOTEelectric
starting.
4. Factorycodefordesignatingoptionalequipment.
5.Specificationletter(advanceswhenfactory
makesproductionmodifications).
WARNING\ Onan uses thissymbol
'throughoutthe text towarnof
possible injuryordeath.
This symbolis used towarnof
possible equipmentdamage.
MANUFACTURER'S GENERAL
WARRANTY
Manuraccurerextends(otheoriginalpurchaserofGoodsforuse.ihefollowing
warranties,subjecttothequalificationsindicated:
HIManufacturerwarrantssatisfactoryperformancefora periodofone(I)yearfromthe
dateeachproductisplacedinservice,solongassuehproductisinstalled,operatedand
servicedinaccordancewithManufacturer'swritteninsinjctions.THISWARRANTY
ISINLIEUOFALLOTHERWARRANTIES.EXPRESSEDORIMPLIED.
INCLUDINGFITNESSFORA PARTICULARPURPOSE.
<b) Manufacturer'sliabilityandpurchaser*'soleremedy fora failureofGoodstoperform
aswarranted,andforanyandallotherclaimsarisingoutofthepurchaseanduseofthe
Goods,includingnegligenceonthepartofManufacturer,shallbelimitedtotherepair
orreplacementofGoodsreturnedtoManufacturer'sfactoryoroneofitsAuthorized
ServiceStations,transportationprepaid.Thecostofanylaborincludedshallbeas
specifiedinManuracturerswritteninstructions.MANUFACTURERSHALLIN"
NOEVENTBELIABLEFORINCIDENTALORCONSEQUENTIAL
DAMAGES.
(clAllclaimsshallbebroughttoManufacturer'sattentionwithinThirty(30)daysafter
discoverythattheGoodsfailedtoperformaswarranted,butinnoeventshalla claim
beacceptedafterone(1)yearfromthedatesuchproductisplacedinservice.
Nopersonisauthorizedtogiveanyolherwarrantyortoassumeanyotherliabilityon
Manufacturer'sbehalfunlessmadeorassumedinwritingbyanOfficerof
Manufacturer,andnopersonisauthorisedtogiveanywarrantyorassumeany
liabilitiesontheManufacturer'sbehalfunlessmadeorassumedinwritingbysuch
Manufacturer.
NNESOTASS4I2
TABLE OF CONTENTS
GeneralInformation1
Specifications2
Installation3
Operation14
Maintenance17
Adjustments21
PartsCatalog27

SPECIFICATIONS
Nominaldimensionsofset(inches)
6.5NH(PriorSpecD)-...20-13/16"H x 20-9/16"W x 29-9/16"L
6.5NH(BeginSpecD)20-13/16"H x 20-9/16"W x 29-5/8"L
6.5NH(ContractorModel)31"H x 28"W x 36"L
Numberofcylinders(horizontallyopposed)2
Cubicinchdisplacement60
Cylinderbore(inches) 3.562
Pistonstroke(inches) 3.000
RPM(60hertz)1800
RPM(50hertz)1500
Compressionratio7:1
Oilcapacity(quarts)4
withfilter4.5
Ignition
RemotestartingBattery
ElectricstartingFlywheelmagneto
Batteryvoltage12
Batterysize72AH
Batterychargerate(amperes)PriorSpec.D 5-Hi
BeginSpecD 1.5to6
ContractorModel1.5to2
VentilationRequired(cfm1800rpm)
Engine(Pressurecooling)570
Engine(Vacu-Flocooling)650
Generator100
Combustion25
ACvoltageregulationin±%7
ACfrequencyregulationin% 5
Rating(outputinwatts)
50hertz(Generalutilityrating)5500
60hertz(Generalutilityrating)6500
SparkPlugGap— Gasoline 0.025
SparkPlugGap— GaseousFuel0.018
NOTE: Hertzisa unitoffrequencyequaltbonecyclepersecond.
TUNE-UP SPECIFICATIONS
SparkPlugGap
Gasoline025"
Gaseous018"
BreakerPointGap020"
IgnitionTiming220
TappetAdjustment(enginecold)
Intake003"
Exhaust010"

INSTALLATION
Considereachinstallationindividually. Use these
instructions asa guide in obtaining a safe and
efficientinstallation.Consultyourlocalbuilding
inspector for information on localbuildingcodes,fire
ordinances,etc.beforeinstallingyourgeneratingset.
Someimportantinstallationconsiderations are:
•Location and Mounting
•Sufficientventilation and cooling
•Fuel and electricalconnections
•Exhaust gas discharge
LOCATION AND MOUNTING
Provideaprotectedlocationthatisdry,dust-freeand,
preferably,heated in coldweather.Allow at least 24
inchesaround the installation for service and
maintenance ofthe unit.Figure1 illustratesatypical
installation fora pressure-cooledgenerating set.
Permanentinstallationsneedasturdy,levelmounting
base of concrete,heavywood,structuralsteel or
othersturdysupport at least 12 incheshigh toaid
routinemaintenance,operation and service.
LOCATEBASE TO ALLOW
ATLEAST •24" SPACE ON
ALLSIDES
FIGURE1.TYPICALINSTALLATION
CARRIAGEBOLT
SQUARE NUT
LOCKWASHER
FLATWASHER
SNUBBER
GENERATOR OR
OILBASEMOUNTING
FOOT
CUSHION
MOUNTINGSPACER
BUSHING
FLATWASHER
FIGURE2.VIBRATIONISOLATOR
Assemblethevibrationisolatorsasshown in Figure2.
Thespacerbushingpreventscompression ofthe
snubber or upperrubbercushion. Two vibration
isolators arefor theengine-endonlyand twoarefor
thegenerator-endonly.Usethem in theirrespective
positions to avoidundesirablevibrationresulting
fromimpropercushioning. The spacing forthe
mountingbolts is 18-5/16" x 12" prior to Spec D;
beginSpec D, spacing is 17-5/16"x,12".
VENTILATION AND COOLING
Aircirculation is needed to dissipateheatproduced
by the engine and generator in normaloperation.
Outdoorinstallationscanrely on naturalcirculation,
butindoor or housedinstallationsneedproperly
sized and positionedvents for requiredairflow. See
Specifications fortheair requirements.
Ventsizesdepend on variableconditions:
1. Size of enclosure
2. Ambienttemperature
3.Electricalload
4. Runningtime

5.Restrictionsimposed
shutters or filters byscreens,louvers,
6.Prevailingwinddirection.
Rememberthat a requiredvolume ofair mustreach
theunit,absorb the heat, andbe dischargedaway
from the installation.Pressurecooledunitsneed an
inletventwith an unrestrictedopening ofat leasttwo
squarefeet.Useauxiliaryfans to increase air flow to
unitsinstalled in small,poorlyventilatedrooms. The
fansize and locationshould be suchthatthe air inlet
to the enginedoes not exceed120° F whenrunning at
fullrated load.
IFEXHAUSTLINEMUST BE PITCHED
UPWARDCONSTRUCT A TRAP OF PIPE
FITTINGS AT POINT OF RISE
AVOIDSHARPBENDS
4DRAINCONDENSATIONTRAP
PERIODICALLY
]
FIGURE 4. CONDENSATIONTRAP
PressureCooling:Theseunitsneed an unrestricted
airinletopening of2-1/2 squarefeet.Install a
separateduct to accommodatethedischargeair.The
dischargeductmust beat least as large asthe inlet
vent. Ifa screen is used in theduct,increasetheduct
sizeproportionately tothe screen'srestriction. Use
large, radiuselbows for bendsandincrease the duct
size for runs of over 5 feet. A canvassection inthe
ductpreventstransmission of vibration. A slight
upwardpitch inthe ductletsheatescapewhen the
unit is stopped and minimizesvaporlock.SeeFigure
1.
Vacu-FloCooling:Provide anair inletarea of 2-1/2
squarefeet.Duct the heated air from the Vacu-Flo
scroll. It should be at leastaslargeasthescrolloutlet
(Figure 3).
WARNING DonotusedischargeVacu-Flo
air forheating
because it may containpoisonousgases.
WARNING Plan
the exhaustsystemcarefully.Exhaust
gases are poisonous!
CANVAS SECTION
DUCTTOCONVEY
HEATED AIR OUT
FIGURE 3. VACU-FLOCOOLING
Vent all exhaustgasesoutside. The exhaustoutlet
mustnotterminatenear air inletventsorcombustible
materials.Avoidsharpbends anduse largeradius
elbows in the exhaustpiping. If thepipingcannot be
pitcheddownward,install a condensationtrap inthe
systemwhere a risebegins(Figure4). The exhaust
lineconnects toa 1-inch NPTFoutlet at the engine.
Exhaustpipingmustnotcomecloserthan9-inchesto
combustiblematerial.Where the systemleaves the
building or enclosure,install a thimble(Figure 5).
SINGLETHIMBLEDIAMETER 12 "
LARGER OR DOUBLE
VENTILATEDTHIMBLE
'•WDIAMETER 6 " LARGER
THANEXHAUSTLINE
HOLES INEND
INNERSLEEVE
EXHAUST LINE PASSING THROUGH
|l WALL ORPARTITION
FIGURE 5. EXHAUSTTHIMBLE
AutomaticEmergencyStopping: The optional
emergencystoppingsystemincludes two separate
devices, the hightemperaturecut-off andlowoil
pressurecut-off.Bothdevices are optionalequip-
ment.
TheHighTemperatureCut-offSwitch(optional) is
locatedintheoptionalairshutterorairduct.Normally
closed, it openswhen theair temperaturereaches
240° F ±6and closesagainwhen the temperature
drops to 195°F ±8.The enginecannot be started
againuntil the switchcloses.

®- 9°° ELBOW ®
^ ~ »—NIPPLE®
JL^REDUCINGBUSHINOQ
(OPTIONAL!
GASREGULATOR @
GASHOSE (fi)
HALFPIPENIPPLE©
EARLIERMODELS
HADADDITIONAL
OUTLETHEREWITH
3A"PIPEPLUG.
^PIPEPLUG
8
-ADJUSTINGSCREW ©
VENT©-INSTALLAFTERADJUSTMENT
MANUALSHUT OFF
GASSOLENOIDVALVE 4GASSUPPLYLINE
• DRY FUEL
FILTER
FIGURE 6. CONNECTIONS FORGAS LINE
The LowOil PressureCircuit(optional)includes a
non-adjustable lowoil pressureswitch and cen-
trifugalswitchlocated onthe engineand a latching
relay inthe controlbox.Thecircuitshutstheengine
down ifoil pressuredropsbelow 7 ± 1 psiand
prevents it fromrestartinguntiltheoperatorpushesa
resetbutton onthe control box.
If lowoil pressureoccurs,thepressureswitchcloses,
completingtherelaycoilcircuit.Therelaypullsinand
latchesafter15 to 20seconds.Thecentrifugalswitch
isrequired to preventthecircuitfromlatchingduring
theenginestartingcycle,before oil pressurebuilds
up.
FUEL
FuelConnection:Forgasoline-fueledgeneratingsets
otherthan the contractorandportablemodelswhich
havetheirownfueltank,connectafuellinetothefuel
pumpinletwhich is threaded 1/8-inch NPTF
(NationalPipeThreadFemale). Usea flexibleline
next to theunit to preventtransmission of vibration to
thefuelline.
Forgaseous-fueledgeneratingsets,checkwithyour
localsupplier forgas regulationsandpressure. See
Figure6.Providea manualgasshutoffanda"drygas"
filter inthe line.Electricsolenoidshutoffvalves are
usuallyrequired for indoorautomatic or remote
startinginstallations (see"Gas SolenoidValve"
following).Alsoinstall a demand-typeregulator ac-
cording to instructions and locate it near the
generating setto aidstarting(regulatorlinepressure
must be within 2 to8 ounces).
AlwaysuseflexibletubingbetweentheengineandgSs-demand
regulator.Usetheshortestpossiblehosebetweentheregulator
andcarburetorforbeststarting.
Seal gas lineconnectionswithshellac or someother
compoundapproved for use in gaseousfuelsystems.
Thread-sealingcompoundswith a leadbase arenot
satisfactory.
GasSolenoidValve:Connect one wirelead to ter-
minal 6 of theprintedcircuitboardusingnumber 18
wire. See Figure 7.Ifnot groundeddirectly tothe
generatingset,connect a commonwiregroundlead
from the solenoidvalve tothe generating set.
GasVacuumSwitch(WhenUsed): If avacuumswitch
isused in conjunctionwith thegas solenoidvalve,
firstconnectonewire of thegassolenoid to ground of
thegenerating setandthe othersolenoidlead to
terminal"VALVE" ofthe vacuumswitch (on intake
manifold). See Figure 7.The terminalmarked
^
1 ^
GASVACUUMSWITCH
GASSOLENOID
VALVE
PRINTEDCIRCUIT
BOARDTERMINALS
FIGURE 7. VACUUMSWITCHCONNECTIONS

"START" of the vacuumswitchconnects to terminal 8
of the generating set control.Terminal"IGN" ofthe
vacuumswitchconnects to terminal 6 (ignition
circuit) ofthe generating set control.
GasolineTank: Ifa separatefueltank is used,install
thetank soits bottom is lessthan 4 feetbelowthefuel
pump. The tank top mustalso be belowthefuelpump
level to preventsiphoning. If the fueltank is shared
withanotherengine, use a separatefuelline.
If the fuel pump lift exceeds four feet, install an
auxiliary electric fuel pump at the fuel supply (not
used with contractor and portable models). See
"Connol Board Remote Wiring."
Anauxiliaryreservoirfueltank is oftenused for
standbyinstallations. For theseinstallations, the fuel
lineconnectionsmust be changed(Figure 8).
FRONT
REMOTECONTROL,
TERMINALBLOCK
ATPLANT
MOMENTARYCONTACT
SWITCH
WIRE
SIZE DISTANCE
#18 to
125 ft.
#16 to
200 ft.
#14 to
300 ft.
#12 to
500 ft.
FIGURE 9. REMOTESWITCHCONNECTIONS
VENT CAP
(Install at least 3 feet
abovereservoirtank)
5/16"VENTLINE
TOEXTERIOR OF BUILDING
\
"l-rV—RESERVOIRTANK
(Mountabovecarburetor
bowllevel)
5/16"FUELLINE
FROMFUELPUMP
5/16"LINE TO
ENGINECARBURETOR
•-3/8" RETURNLINE
TOMAINFUELTANK
SOLID STATE CONTROL SYSTEM —
BEGIN SPEC D
The NH electricgeneratingsetsbeginningwithSpec
Dhave a solidstatecontrolsystemlocated ontop of
thegenerator(Figure 10)for starting,stopping,
batterycharging, andlow oil pressureshutdown.
Theelectricgenerating set control,comprised
basically of a printedcircuitboardabout4inches by 7
inches, has two controlswitches.Start-stopswitch is
located onthe rightside of the control.ROPESTART
switch(calledHANDCRANK — ELECTRICorNON-
FUNCTIONAL on somemodels) is located onthe left
side.
FIGURE 8. AUXILIARYRESERVOIRFUELTANK
REMOTE START-STOP CONTROLS
Standardstart-stopcontrols for Onanremotestarting
generating set consist of asingle-pole,double-throw,
momentarycontactswitchconnected by threewires
to the set'sremotecontrolterminalblock.Pushing the
switch up engages the starter; the centerswitch
position isfor running;pushingswitchdownstops
theplant.
Tocontrol the generating set fromseverallocations,
installseparateswitches and wirethem in parallel
(Figure 9). Any number of switches may be used.
ROPE START
SWITCH
P.C. BOARD
TERMINALS
I THROUGH9
START-STOP
SWITCH
c
GENERATING
SETCONTROL P.C.BOARD
TERMINALS
10THROUGH 18
FIGURE 10. GENERATOR SET CONTROLASSEMBLY

Thestart-stopswitchispressedtoSTARTuntilthe
generatorsetstarts.TheswitchispressedtoSTOP
untilthegeneratorsetstops.Modelswithswitch
indicatedasROPESTARTorHANDCRANK—
ELECTRIC,usetheswitchformanualropestarting
(modelswithropesheave).Terminals 1 through9 on
theleftsideofthecontrolconnecttothefollowing
components:
a.IgnitionPoints— 6
b.IgnitionCoil— 6
c.StartSolenoid— 9
d. LowOilPressureShutdown— 4
e.Choke— 2
f.BatteryChargingResistors— 7 and8
Terminals10through18ontherightsidearefor
controlconnectionsofa remotecontrolstation
including:
a.DCVoltmeter— 13and15
b.DCBatteryChargingAmmeter— 17and18
c.RunningTimeMeter— 10and13
d. Generator"ON"Light— 10and15
LOAD WIRECONNECTIONS
Thegeneratingsetnameplateshowstheelectrical
outputratingofthesetinwatts,voltsandhertz.The
contractorandportablemodelsareprewiredand
havea receptacleboxwithtwoduplex120-volt(15
ampere)groundingreceptaclesandtwo240-volt(20
ampere)twistlockreceptacles.Fortheother
generatingsets,thewiringdiagramshowstheelec-
tricalcircuitsandnecessaryconnectionsforthe
availableoutputvoltage.TheACoutputboxhas
provisionstoaccommodateloadwiresandislocated
ontopofthegenerator(beginSpecD).SeeFigure11.
Meetallapplicablecoderequirements.A qualified
servicemanorelectricianshouldmaketheinstalla-
tionandtheinstallationshouldbeapprovedbyyour
localbuildinginspector.
Useflexibleconduitandstrandedloadwiresnearthe
settoabsorbvibration.Usesufficientlylargein-
sulatedwires.Striptheinsulationfromthewireends
asnecessaryforcleanconnections.Connecteach
loadwiretothepropergeneratoroutputleadinside
theACoutputbox.Insulatethebareendsofun-
groundedwires.Installa fusedmainswitch(orcircuit
breaker)betweenthegeneratingsetandthe load.
Reconnectible,Single-PhaseGenerator:Voltage
selectiononreconnectiblesingle-phasegeneratorsis
foruseas120/240volts,3 wire;120volts,2 wire;or,
240volts,2 wire(Figure12).Usetheconnectionfor
two-wireservicewhenoneloadexceedsone-halfthe
ratedcapacity.Balancetheloadwhenconnectingfor
three-wireservice.Currentforanyoneoutputlead
mustnotexceednameplaterating.Serious
ACOUTPUT
BOX
FIGURE11.LOCATIONOFACOUTPUTBOXAND
GROUNDCONNECTION

120VOLT. 2 WIRE
UNGROUNDEDLOADWIRE
(BLACK)
120V.(Fullnameplaterating)
GROUNDEDLOADWIRE
Ml. M3
I(JOIN)
(WHITE)
(!)
O
<
UJ
_l
Q:
o
\-
<
|M2. M425
'(JOIN ANDZ
GROUND) UJ
r(D
240VOLT, 2 WIRE
UNGROUNDEDLOADWIRE ^
(BLACK)
240 V. (Fullnameplaterating) £
GROUNDEDLOADWIRE ^
(WHITE) ^
I M3
M1. M4
(JOIN)
M2
tn
a
<
u
_l
OL.
0
H
<
CC
UJ
Z
UJ
O
120/240VOLT. 3 WIRE
UNGROUNDEDLOADWIRE(BLACK)
NOTE: Onlyhalfnameplate
rating canbe taken off each . 240V.
120voltconnection.
T
120V.
Ml
GROUNDEDLOADWIRE(WHITE)
t
M2, M3 (JOIN)
120V.
1. UNGROUNDEDLOADWIRE(BLACK) ^
£m M4
FIGURE 12. SINGLE-PHASE,VOLTAGECODE"-3C"GENERATORCONNECTIONS
overloading can damage the generatorwindings.
Whentwo or moresingle-phasecircuitsareavailable,
divide the loadequallybetweenthem.
Anycombinationofsingle-phaseandthree-
phaseloadsmaybeusedaslongasthe
currentineachline'loadofthegeneratordoesnotexceedrated
current.
Three-Phase,Four-Wire, Wye' Connected
Generators: A three-phase,four-wiregenerating set
producessingle-phasecurrent ofone voltage and
three-phasecurrent of a differentvoltage.Thesingle-
phasevoltage isthe lowervoltage as noted onthe
nameplate, andthe three-phasevoltage is thehigher
nameplatevoltage. See Figure 13.
Terminalmarked MOis grounded. For single-phase
current,connect the neutral(white)loadwire tothe
MOterminal.Connect the "hot"(black)loadwire to
anyone of theotherthreeterminals. . .M1,M2orM3.
Threeseparatesingle-phasecircuits are available,
with not morethanone-third the ratedcapacityofthe
generating set from anyone circuit.
Forthree-phasecurrent,connectseparateloadwires
toeach ofthe generatorterminals Ml,M2andM3.
Single-phasecurrent is obtainedbetween anytwo
three-phaseterminals. If single-phase and three-
phasecurrent aretobe used atthe sametime, use
care to properlybalance the single-phase load.
120/240-Volt,Three-Phase,Four-WireDelta Con-
nectedGenerator:Three-phasedeltaconnected
generatingsets are designed to supply120-volt,
single-phasecurrent;240-volt,single-phasecurrent;
or240-volt,three-phasecurrent. See Figure 13.
Forthree-phaseoperation,connect the threeload
wires tothe threeterminals Ml,M2andM3. . . one
wire to eachterminal.MO is theneutralwireandisnot
used for three-phaseoperation.
Connectthe"hot"(black)loadwiretoeitherthe Mlor
M2terminal for 120-volt,single-phaseservice. Con-
nect the neutral(white)wireto.theMOterminal.Two
120-voltcircuits are available.
CAUTION
DonotuseMOandM3asa 120-voltcircuit.
Forsingle-phase,240-voltservice,connect the load
circuitbetween Ml andM2, or betweenM2andM3, or
between Ml andM3(threecircuitsavailable).TheMO