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Put CH tem p erature
se lec tor to maximum
Ensure extern al
controls are calling
for h eat
Is F3 failure code
shown on lc d ?
YES
Check and if
nec essary repl ace
CH supply / return
sen sor
W as F 8 failure cod e
shown on lcd befo re
re set? Is F 8 shown
after 1 minute?
YES
Check X 4 connectors
for ex amining
switching and fee d back
signals on m ain b oa rd
by osilos cop e.
Check cab le
connections of fan, and
if n ecessary rep lace
fan
or repl ace main
PCB
.
39
Check Central Heating Operation
Is F1 failure code
shown on lc d ?
NO
Does pump run?
YES
NO
Go to Chart IV
NO
Is 24 V dc pres ent on X4-
1-3 terminals?
NO
Check, an d if necessary
repl ace m ain PCB
Chart II
YES
NO
Is 23 0 V AC present on
ter m inal s of pum p and
Chart III
Fan Operation
Re set control if
neccesary
Does fan run?
Re set C ontrol
Check and if necessary
replace ov erheat
thermostat , check pump
Check CH supply sensor
main P CB?
Check External CH
control input s and
YES
Check and if
nec essary repl ace
Main PCB
YES
W as F 8 failure code
shown on lcd b efor e
re set? Is F8 shown
after 1 minute ?
YES
Check fan's cab le
connections
Check cleaning of
fan, and if necessary
replace fan
NO
wiring
Check, and if
necessary replace
main P CB
NO
Go to Chart I
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