Fault Finding; Introduction; Logical Fault Finding Procedure - Vaillant turboMAX pro 24/2 E Instructions For Installation And Servicing

10 Fault Finding

10.1 Introduction

The turboMAX pro has built in diagnostic indicator lights
to assist you with fault finding in the unlikely event of a
boiler malfunction. The lights will illuminate in sequence,
indicating the operational status of the boiler. Should a
fault develop in the boiler the indicators may flash high-
lighting the possible fault e.g.
Power on indicator (green)
Illuminates when the electricity supply to the boiler is
on, the main on/off control is set to position (I) and the
internal boiler fuses are o.k.
(A flashing indicator shows that the overheat thermost-
at has cut out.)
Hot water demand indicator (yellow)
Illuminates whenever there is a demand for hot water
i.e. a hot water tap is opened.
Central heating demand indicator (yellow)
Illuminates whenever there is a demand for central hea-
ting i.e. the radiator temperature control is turned on
and the external heating controls are calling for heat.
Note!
If the external controls are not calling for heat
(i.e. the room thermostat has reached
temperature) this indicator will go out. This is
perfectly normal.
Fan operation indicator (yellow)
Illuminates to indicate that the fan is operating and has
been checked by the fan pressure switch.
(A flashing indicator shows that the air pressure switch
has not made.)
Ignition indicator (yellow)
Illuminates when gas valve, operator and ignition trans-
former are energised. This indicator remains on during
burner operation.
(A flashing indicator shows lack of water or poor water
circulation in central heating system.)
Flame indicator (yellow)
Illuminates when flame is recognised by the flame moni-
toring system.
(A flashing indicator shows that an NTC sensor is bro-
ken, not connected or shorted to earth.)
Burner lockout indicator (red)
Illuminates if the burner fails to light within 10 seconds
of illumination of the ignition indicator after the 3rd igni-
tion cycle.
(A flashing indicator shows a failure in the electronic
boards.)
Instructions for Installation and Servicing turboMAX pro R3
To reset the appliance after a lockout (either burner
lockout illuminated or any other indicator light flas-
hing), turn the central heating control to the reset positi-
on and release.

10.2 Logical fault finding procedure

Preliminary Checks
These checks must be carried out before attempting to
use the fault finding guide:
1) Carry out electrical safety checks.
2)Check that the external electricity supply to the boiler
is on, and a supply of 230 V~ is present
between boiler terminals „L" and „N".
3)Check that gas supply to the boiler is on and that it
has been correctly purged.
4)Ensure the heating system is full of water and charged
to approx. 1 bar. If not refill the system and vent
system. Ensure boiler flow and return service valves
are open.
5)Check that boiler main on/off control is set to position
(I)
6)Ensure that the Maximum Radiator Temperature and
Maximum Hot Water Temperature controls are set to
high position.
7)Check that all the external controls are on and calling
for heat (if no external controls are fitted, boiler termi-
nals 3 and 4 must be linked). Check that boiler anti-
cycling „economiser" control is not engaged.
Procedure
Note!
Always check the operation of the boiler for
central heating first before checking hot water
operation. Do not open a hot tap unless
instructed to by the fault finding guide.
Fault Finding 10
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