VaillantTraining/LogicalFaultFindingGuidefor allCOMBlcompact and THERMOcompact models

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Contents

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GuidanceNotes

IICD

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RoomSealedFan FluedModels(RSF)COMBlcompactVCW 242E,282ETHERMOcompactVC112E,142E,182E,242E,282E

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.BalancedFlue&OpenFlueModelsCOMBlcompactVCW221,240,280THERMOcompactVC110,180,240,221.

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[!]Guidance Notes(should be readbeforeusing this faultfinding guide)

1. Check you are using correct guide for your appliance.See index and check model number.

2.Always start at the beginning of guide and workthrough one step at a time.

3.AII guides deal with central heating (C/htg) first, thenhot water (D.HW.)Do the same when following guides.

4. When checking 240v AC mains voltage use terminal 1on appliance terminalstrip as the neutral test point.

~ 5. When checking D.C. voltage use terminal9 onappliance terminalstrip as the negativetest point.(All D.C. voltages are low voltage).

10

56

1

Q7

Note 1 It is law*that any work carried out on a gasappliance must be carried out by a competent personwho is registeredwith CORGI (Council for RegisteredGas Installers).Note 2 All work involvingelectricitymust be carriedout by a competent person who is responsible forelectrical safety checks.

*Gas Safety (Installationsand Use) Regulations 1984Gas Safety (Installationsand Use) AmendmentRegulation 1990

6.ln order to use this fault finding guide ensure thattheoperating mode of circulatingpump is set to operatingmode (I) (selector plug adjacent to appliance terminalstrip makes electrical connection to contact one) seediagram.T

IISI0Gro GroG

7. Note that illustrationsand pictures are shown onlyonce and are not duplicatedagain in this guide.Each illustration/picturehas been given a referencenumber.

93

FRONT CONTROL PANEL

Key1. Yellow neon indicatingpower to operator.2. Green neon indicatingoperation of Diaphragm pump.As voltage decreases to diaphragm pump so neon losesluminosity.3. 0.16 amp anti surge fuse.4. Time delay adjustment (factoryset 5 minutes,adjustable 1-12 minutes).5. Fault suppression button(ignition lockout).6. Indicatingneon (lockout).7. 2 x 2 amp fuses (L&N).8. Variable potentiometercontrollingcentral heatingflowtemperatureonly.9. Red neon rocker switch for power on.10. Central heating rocker switch (not fittedon VCappliances).

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Room Sealed Fan Flued Models (RSF)

guidancenote6)

Q.

11

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(c) Check appliance not in time

delay (isolatepower, wait 5seconds and restore).

(d) Check anti surge fuse(0.16 amp)....

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Inoe. pU\pPrun1

tYES,

[ Goill 4

~CheckhydraulicoperationOK ?1.HydraulicdivertervalvemovesleftclosesmicroswitchM2(VCWonly)T

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2. Differentialvalveopens.T Pic14

[Goto5

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~NO"(a)Check240vACacrosspumpterminalsT Pic10

(b) Checkpumpfreeto rotateandnotstuckT Pic11

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I tvIf(a)and(b)areOK.- changepump.

I~NO

(a)Checkapplianceandsystemfull,pressurisedandventedofair.

(b) Checkservovalveis inC/htgposition,returnspringholdscarndown(VCWonly).T

(c) Checkfordirt,sludge,fluxor inhibitorcausTngfrothinginsystemaffecting:-1. Pumpperformance2. Hydraulicdivertervalve(VCW only)3. Servovalve(VCW only)4. Connectingtubes5. Mainheatexchanger6. Differentialvalve

Pic12

M3OPEN G

Rearview

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~DoesapplianC1ignition?T

~(yellowneonglowingfrontcontrolbox)

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YES

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~VaillantHEATING,CONTROLS,HOTWATER.

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I~O~ (a)CheckmicroswitchM2(20vDC)ismakingcontactandclosedcircuit(VCWonly).T

(d)Checkcombustionchamberseals.(e)Cneckairswitcn"tubeskinkedandSl

., topcoverplateclear.T

Pic15

(b)Checkfanpressureswitchoper9tes(240vAC:frombothsidesof switchtoneutralterminal1)ifnotcheckC to FT Pic16

(c) Checkflueinstallation:-Joints correctlylocated- Fluenotblocke(- Terminalposition

(1)Checkfanworkingcorrectly.If allaboveOK changefanpressureswitch.

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Does burner light and

remain alight?

~YES

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~VaillantHEATING,CONTROLS,HOTWATER.

~NO~ N;B. For lockoat (Blackbutton & Red Neon)problems when no flame isvisible check A to F.T

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\)~rnenflame is visible priorto lockout checkFto H only(a).Check gas supply toappliance live and purged.(b).Check differentialvalveopen (if no returnto Q4).(c).Check20v DC acrossgas operator, if availablebut operator fails to open(audible click) changeoperator.T

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(d).Check central heating'overheat thermostatand

connection (should beclosed circuit, if openchange component).T b" Pic22

71

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~YES

~Goto8

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YES

~VaillantHEATING,CONTROLS,HOTWATER.

I~O~(a)Checkstandingandworkinggaspressureatapplianceinlet.T Pic25

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(c) Checkvoltageacrossdiaphragmpump(approx6vDC)withNTC disconnected.T Pic27

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(b) Checkdiaphragmpumpoperatingtubesandthrottlejetclear.T Pic26

NO~ (a)TestNTC/Elebtronicboard.PulloffNTC wire(fromD.H.W.overheat)touchitonchassis,if burnergoesoff,changeNTC.T Pic29

(d) Checkburnerpressuresettingslowandhighfirerate.T Pic28

(e)Checkand/orreplacegasoperator.

If burnerstaysonchangeelectronicboard.

(Thegasoperatormaybestuckopenegdebris.Thissymptomis veryunlikelybutcanbecheckedbypullingoffthewiretooperator.Ifburnerremainsalightthenchangeoperator).

~VaillantHEATING,CONTROLS,HOTWATER.

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(a) Check demand for hotwater-tap open and supplypipes correct way round.(b) Check water sectionmoves servo valve cam - if

not check venturi/diaphragmof water section...

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~YES

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Pic 30

(c) Check microswitChM3(20v DC) is making contactand closed circuit... Pic31

(d) Check hyvalve movesmicroswitch r

open no eTecthrough switch)...

M3CLOSED ~

(e) If Dcheckgas -pressure at& burner pr'Pic 25 & Pic 28.

(1)If water fl