53
®
FAULTS AND FAULT FINDING
The Fault Display
The unit carries out a number of internal and external checks during operation. If a fault is found, a fault
number is used to identify the type of problem. A list of fault numbers may be found later in this sec-
tion.
Depending on the type of fault, the unit may perform a safety shutdown of the burner and activate the
alarm relay.
For details of how to restart the burner after a fault has occurred, refer to “When a Fault Occurs”.
Description
Many of the faults detected and displayed by the unit will cause a safety shutdown of the burner. Other
faults will be displayed as a warning but operation of the burner will not be affected.
Each fault number is prefixed on the commissioning display by a letter. This letter describes the status
of the fault:
F
This means that a fault has occurred and is still present. The fault may be
internal or external to the unit.
C
This means that a fault did occur but has now cleared.
For example:
F60
Means fault 60 has occurred and still exists.
C73
Means fault or alarm limit 73 has occurred but has subsequently been recti-
fied. This is known as a cleared fault.
When A Fault Occurs
To cancel the alarm relay, briefly press the FAULT MUTE (reset) key on the user display. A separate
FAULT MUTE (reset) switch will be REQUIRED if no display is connected.
Using the NX550 display:
Use the Engineer’s select key
to view the
FAULT NUMBER
and look up the fault num-
ber(s) shown, to discover why the fault occurred.
If all faults which caused a safety shutdown have cleared, hold down the
FAULT MUTE
key for
approximately three seconds to remove the faults and re-start the burner.
The function of the
FAULT MUTE
key may also be achieved using the
FAULT MUTE
(reset)
input.
Using the LED Display:
If a fault is present, the red fault lamp will be illuminated and the fault ‘number’ will be displayed as a
code by the 7 green lamps on the control unit. Refer to Fault Listing to determine Fault Code.
If all faults which caused a safety shutdown have cleared, hold down the
FAULT MUTE
(reset) key for
approximately three seconds to remove the faults and restart the burner.
The function of the
FAULT MUTE
(reset) key may also be achieved using the
FAULT MUTE
(reset)
input.
Non-Volatile Lockout
If power is removed from the unit while a fault is still present, the fault will be stored in non-volatile
memory. When power is restored to the unit, the fault number will still be present and it will be nec-
essary to remove the fault before restarting the burner.
Fault Subsets
As an aid to fault finding, most faults also have a fault subset which gives additional information
about the type of fault or what the burner was doing when the fault occurred, these are only available
using the commissioning display or via Comfire. Where applicable, the subsets are given in the fault
listing.
To view a fault subset press the engineer’s key
.
