Worcester HEATSLAVE 9.24 RSF

19 . TO REPLACE THE SPARK ELECTRODE CABlE
{See Fi gs. 44 a nd 4 5.)
(a! Pull the c ab le o ff !h e s pa j e connec tor on th e spa1k
e lect rod e.
(b I Remove th e sea ling cov er on the bo tt om of the boiler casing
held in p osit i on wi th one M5 screw . Feed the spark
electrode cable
th rough the hole in the boi le r casing.
(c) Pu llt hecableoff theelectricalco nn ecdononthesequence
co n trol board posi tio ned at the to p ri ght -hand comer.
Rem ove the cable threading it through the hole in the r ea r
of the
elect ric al pa nel.
(dl
Hin ge the e lect r ic al t ra y d ownwards by fo l lowi ng the
ge ne ra l notes pr ior to In st ruction 7.
(e) Rernove the cable cla mp sec:u ring the spark electrode cable
fr orn th e rear of the electrical pa n ~l.
(f ) Remove the cable threading it through the ho!e in the rear
of the ei ect rical pane l.
!gl Re mo ve the t wc prot ect ive sl eeves from th e spark
eiectrode cable.
lhl A ~ pl ace the new cab le i r. th .o:! rever se order and ens ur e:
i) The s ea ling cover is replaced ar.d seals the casing.
i
i) The electrical con n ect ion is made to the termin al on
the seque n ce cont rol boa;d ma rked HT 1md
positioned
at the top rig ll t-hand corner.
20 . TO REPLACE THE ELECTRONIC DRIVER BOARD
!See Figs. 4 3 and 44.)
(a} Rem ove the ta n pressure s witch as described in Part 18a ,
b !:!lid c.
f bl Release t he p tas tic ca tch on the end of each mounting p ost
pulling the printed ci rcuit board f orwar d approximate!y
3 rn m to preve nt the pia st ic ca tc h from returning.
fc} Pull the board offt he remainderof th emouming posts un ti l
it is free.
(d) Grasping the board
f irm ly pull off the electrical edge
connect ion, the tempera ture cor~trol connection and I he
two - way Mo l ex pl ug ..
tel Remove the plast ic pres su re adjust ment sp in dle from the
rear
of the driver an d insert int o the replacement dr iver
board.
{f ) l.ocute the elec tr ical edge con nect or in place and push on
to the printed ci rCU it b oa rd. The edge cor"~necto r has three
ribs
wh ich lo c at e into three m atc hing slots in the board so
ensuring correct
orientatio n.
Similarly reco nn ect the temperature con trol and th e two -
w ay
Mol ex plug.
(g) Locate
the new board over the fo ur mountin g posts and
push back
squarely until the plastic cat ch on the end of each
pos t clicks in to place.
(h) R
ea ssemble the fan pressure switch in th e reverse order
as de.scribed in Pa rt 18 d.
21 . TO REPlACE THE TRANSFORMER
(Figs. 44and 45 .)
(a) Follow the wires from th e t ra nsformer to the main term inal
blo ck and di sc onne ct the blue. br own , oran ge an d black
wire s from ter minals N, 6, 12 and 13 respectively.
(hi R emove the two M4 t ap tit e sc r ews securing the
transformer inside t Me elec tr ic11 l cover.
(c) Rem ove the transf orm er a nd the paxol in insul at ion.
(d) Re
fit a new tra ns fo r mer in the rever se ord er . The ho les in
t
he paxolin in iu l ation are off centre and the insulati on
40
shou ld be replaced w i th the wide sect i on un der the
transformer
el ec trical co nn ec tions.
22 . TO REPLACE THE SUPPRESSOR
(fij g, 44 .)
{a) Th e suppressor is located to t he le ft of the term in al bl oc ks
and
held by a 'P' clip sec ur ed by a scr ew . Re move the screw
a
nd ease t he sup pr essor clear of the bracket.
{b) Di
sconnect the suppressor lea ds fr om t ermina!s N 2 an d 4
on the te rminal strip and remove.
(c) Replace with a new suppress or and reassemble i r. re verse
order.
23 . TO REPLACE THE SEOU ENCE CONTROL BOARD
(F i gs . 44 a nd 45.)
(a) R emove the transfor me r as described in Part 2 1 b a nd c.
(b) Pull the spark electrode cable oit the electrical connection,
at
the t op right h and corner oft he sequence control board,
ma rked HT .
(c) Disconnect the f our Moiex plugs noting their pu!iition:;.
ldl Release the plast ic catch on the end of each mo unt ing po st
pulling the p ri nted cir cu it boa rd forward ap pr oximately
3 mm to pre vent the pl astic eaten from r e tu rn f r ~ g.
iel Pu ll the board of f the re mainder of th e mou nt i ng p ~a te unt it
it is free.
m L oca te the new boi!lrd ov er the f t>ur mount ing po sts and
push back squa rel y until the plast ic catch on the end of eac tl
post clicks into place.
(gl Reassemble in the re verse order and ensure:
i) The spark electrode cable is connect ed to t he terminal
ma rked HT at the top r igh t -h and co r ner of the
sequence control board.
iil The
Mo lex plugs are fitte d to the correct termi na ls.
Plugs are not interchangeable and w ill only f it the
socket th ey wete removed from.
24 . TO REPLACE THE 3·POSITION SWITCH
(a) Remove the push-on co n ne ct io ns from the rear of the
switch taking no te of th ei r posit io ns.
(b ) Squee ze togeth er the t wo plastic re tai ni ng lugs and remove
the swi tch from the f ront of th e faci a.
(c) Snap in the replaceme nt switch and with the aid of the
wiring difigram . See Fi g. 27. Co nn ect the push -on
connectfon s.
25 . TO REPLACE THE PROGRAMMER ASSEMBLY
lal R emove the clampi ng bracket f rom each end of th e
progr(lmmer
by unscrewing the four M4 tapt ite screws
retaining
them to the facia.
{bl Re move the old programmer comp l ete w ith it s wi ring
harness and
front b ez el.
(c) R ei it the new programmer in the reverse order complete
w
it h it s new bezel and w f ri ng harness using the old
cla mp ing brackets and screws.
26 . TO REPLACE THE CENTRAL HEAT I NG SENSOR
Ch ec k that the e lect ri ci ty supp ly has been turned off.
(a) Turn o ftthe CH f low and re turn connections to t he boiler
and drain the
appliance.
lbl Pu ll oH t ne two wires from the sensor and un screw the
sensor.
{c) Fit
the n ew sensor and reconnect the two wires.
{d)
Open the v11lves an d reffll the system venting as necessary.