Vaillant COMBlcompact VCW240 - Burner Modulation to Low Fire and Shutdown

~ Vaillant
HEATING,CONTROLS,HOTWATER.
@
(a) Check demand for hot
water-tap open and supply
pipes correct way round.
(b) Check water section
moves servo valve cam - if
not check venturi/diaphragm
of water section.
..
~o~
~
YES
!
Pic 30
(c) Check microswitCh M3
(20v DC) is making contact
and closed circuit.
.. Pic31
(d) Check hy
valve moves
microswitch r
open no eTec
through switch).
..
M3
CLOSED
~
(e) If D
check gas
-
pressure at
& burner pr'
Pic 25 & Pic 28.
(1) If water fl<
insufficientc 0
adequate cold water mainO,
supply and/or blockage in
water section or DHW
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