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Fig.74a

Fig.75

Fig.76

page68

15.2Air/GasValveSetupProcedure

Thepreferredmethodistouseamicromanometerasoutlinedbelow,howeverifamicromanometerisnotavailableacombustionanalysermaybeusedasdescribedbelow.

UsingaMicroManometertoadjustthevalveoffset.

ProceduretocorrectlysetnewAir/GasValveusingamicromanometer.Connectthemicromanometerwiththeapplianceofffannotrunningasbelow.

1.Loosenscrewintheinternalpressuretestpoint(PINT)andconnectto+(positive)sideofdifferentialmicromanometer.

2.Teethe(negative)sideofthemicromanometerintotheairsensetube(Fig.77).

3.EnsuremicromanometerisinPaormbarscaleandhaszeroedcorrectly.Ifindoubt,rezerotheinstrument.

4.UsethechimneysweepfunctiontoenableeitherEngineorSupplementaryminimumrate.Beforetheair/gasvalveopens,thepressureshownshouldbenegativeie.30Pa

or25Parespectivelyforeachburner.

5.Whentheburnerlightsseethatthereadingis5to6Paifoutsidethesevaluesusetheoffsetscrewtoadjustthe4mmhexheadunderneaththedustcover.

NOTE:Turningadjustmentscrewclockwisereducesnegativedifferential;anticlockwiseincreasesnegativedifferential.

A4mmhexagonkeyshouldbeusedtomaketheadjustment.

6.NowcheckthecombustionCarbondioxideandCarbonMonoxideatthemaximumrateforeachair/gasvalve.

UsingaCombustionAnalysertoadjustthevalveoffset.

Followtheprocedureasoutlinedinsection15.1.paragraph16toadjusttheCarbonDioxidepercentageatthemaximumrate.

ForthesupplementarytheCO2shouldbe9.0%±0.3

FortheenginetheCO2shouldbe9.0%±0.3

PropaneGasWheneitherburneristestedindividuallyatmaximumrate:TheCO2shouldbe10.2%±0.3.

1a.ToadjusttheoffsetchecktheCarbonDioxidepercentageattheminimumrate.Removetheoffsetadjustmentdustcoverusingaflatbladedscrewdriverandadjusttheoffset

usinga4mmhexdrivertogivethefollowingpercentages:

SupplementarytheCO2shouldbe8.7%±0.3(minimumrate)

EnginetheCO2shouldbe8.8%±0.3(minimumrate)

PropaneGasCO2atminimumrate:

TheCO2shouldbe9.6%±0.3forthesupplementary

TheCO2shouldbe9.8%±0.3fortheengine

2a.RechecktheCarbonDioxide%atmaxrate,adjustthethrottleadjustmentscrewifnecessary.

3a.Thedifferencesbetweenthemaximum/minimumpercentagesshouldbeascloseaspossibletothedifferencesintherangesquoted;theymustnotbeequalorless.