Technical data

53
Storage tank has overheated.
This is a serious fault.
Call Service Engineer.
FAIL POINT I
Is flue correctly
installed and free of
blockages?
FAIL POINT J
Yes
Replace flue gas safety
device (TTB).
If this fails to solve the
problem then replace
control board.
Flue gas detected inside
boiler.
Note 1:
It is possible that during
extreme weather
conditions this fault may
occur intermittently.
Note 2:
Lights will flash until
detector thermostat self
resets.
Yes
Check air/gas
channels in
gas/water heat
exchanger. Are they
free of restrictions?
No
Unblock/rectify
fault.
No
Clean or replace heat
exchanger.
FAIL POINT K
If the boiler has developed
erratic or poor
performance and the
above information has not
satisfactorily located the
fault, the following
information may be useful:
Temperature sensors:
These are critical to
provide temperature
information for the control
system.
Check they are fitted
securely with conductive
paste. May be out of
tolerance.
Control board:
May have component
failure.
Gas Valve:
Modulating valve may be
sticking.
Burner:
May not be cross-lighting
effectively.