Introduction; Logical Fault Finding Procedure - Vaillant TURBOmax Pro 28 Instructions For Installation And Servicing

Fault finding

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
highlighting 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 ( ) and the
internal boiler fuses are o.k.
(A flashing indicator shows that the
overheat thermostat 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 heating 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 transformer 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 monitoring system.
(A flashing indicator shows that an
NTC sensor is broken, 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
ignition cycle.
(A flashing indicator shows a failure
in the electronic boards.)
To reset the appliance after a lockout
(either burner lockout illuminated or
any other indicator light flashing),
turn the central heating control to the
reset position ( ) and release.

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.
FAULT FINDING
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 ( )
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
terminals 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.
57