Halstead Ace High, Инструкции по установке и обслуживанию, Страница: 27 / 40

25
FAULT FINDING
8
8.1 GENERAL
8.2
DIAGNOSTIC INDICATOR LED’S
8.3 IGNITION FAULTS
8.4
DHW FAULT FINDING
8.5
CENTRAL HEATING FAULT FINDING
Before looking for a fault condition, check that:
The mains electrical supply is turned on.
The clock and / or room thermostat (if fitted) are calling for heat
(CH 'faults' only)
The gas service cock is open.
The DHW and CH isolation cocks are open.
The system is at design pressure.
Before attempting any electrical fault finding, always conduct the
preliminary electrical system checks as described in the Instructions
for the British Gas Multimeter or other similar instrument.
On completion of any service or fault finding operation involving
making or breaking electrical connections always check for EARTH
CONTINUITY, POLARITY, and RESISTANCE TO EARTH.
Detailed procedures for replacing faulty components are described
in section 9 (Parts Replacement)
The LEDs on the fascia panel (Fig. 30) show the status of the boiler
as described below:
Power ON LED illuminated. (Green): Boiler is in service. If no
other LEDs are illuminated, the appliance is awaiting a demand for
heating or hot water.
Burner ON LED illuminated (Green): Burner is alight.
Hot Water LED illuminated (Green): Boiler is in DHW mode.
Heating LED illuminated (Green): Boiler is in Heating mode.
Safety Lockout LED illuminated (Red): Burner has failed to light
and gone to ignition lock-out and possibly overheat cut-out. Re-set
the appliance by turning the mains switch through to the Reset
position (spring return) and if necessary, re-set the button on the
overheat thermostat (left hand underside of casing).
NOTE: There may be a fault condition preventing ongoing
operation of the appliance. Follow fault finding procedure.
In the event of the boiler failing to light, investigate the problem by
following the flow chart.
When the hot water tap is turned on, the controls should carry out
a set of start up checks (flow chart 1) followed by an ignition
sequence (flow chart 2)
If the control has powered up correctly but does not respond to a
DHW demand, investigate in the following order:
Check for 0V d.c. across pins 10 and 11 on X4. If 5V is present
across pins 10 and 11 check water flow switch and wiring.
If 0V is present, check DHW thermistor and wiring. If DHW
thermistor and wiring are OK, replace PCB.
If DHW temperature heavily fluctuates during a long draw off
and occasionally goes in an overheat Lock-out condition, check
the secondary plate heat exchanger for debris and replace.
Upon a demand for Central Heating, (closure of the time switch
and room thermostat if fitted) the appliance should respond to the
demand.
If the control does not respond to a CH demand, investigate in the
following order:
If 230 Va.c. is present across pins 1 and 2 on X1 but no start up
procedure occurs ensure that the control is not in anti-cycle mode
by removing power from the control and restoring it after a delay
of 10 seconds, or open a hot water tap for a few seconds.
If the control still does not carry out start up checks, check CH
thermistor (pins 12 and 13 on X4) and wiring.
If CH thermistor and wiring are okay, replace PCB.
NOTE: Whenever a CH demand is removed, either by the
timer, the room thermostat or the boiler internal
temperature control, an anti cycle mode is initiated which
prevents the boiler firing in CH mode for 3 minutes.