51
Hoval STU Wood Pellet Boiler
Appendix - D
Operating, Cleaning and Fault - Finding Procedures
In The Event of a Fault Condition/ Power Interruption
1) In the event of a fault condition turn the
“Kindle/off/auto”
switch on the wood
burner control panel to the
“Off”
position.
This will remove the call for the boiler to run, but will keep the safety devices on the
boiler active.
2) Do
NOT
turn the motor isolators off; this will render the safety devices inactive.
3) Do
NOT
attempt to run the boiler again until a Suitably Qualified engineer has
investigated and rectified the fault.
The following Items will cause a Fault Condition and will record a message on the
LRP unit.
FAULT
CAUSE
First High Limit:
Boiler water temperature has reached
85°C due to circulation/heat
dissipation Problems resulting in
boiler creep.
Second High Limit
Boiler water temperature has reached
(Manual reset):
95°C due to Circulation Pump Failure
or a power interruption.
Burn-back
Fire has tracked back along the
Thermostat initiation:
conveyor tube. Possible causes are:
Conveyor motor tripped (see below)
or shear pin failure, burn back
thermostat malfunction or a prolonged
power interruption.
This can also be caused by leaving
the ID fan running continuously on the
AUTO/ID FAN ONLY selector switch.
Motor Trip
:
One or more thermal over loads have
tripped preventing the motor(s) from
running.
Oxygen High:
Fire has gone out in the retort.
Oxygen Low:
Products of combustion are not being
removed from boiler.
Incoming Phase Fault:
Phases on incoming power supply
stoker control panel have been
changed up stream of panel.
Ignition system (where
Fault with the hot air ignition unit
fitted) fails to light
the
Alternatively, if the boiler flue gas
fire-bed:
temperature is greater than 50°C, the
system will not operate the ignition
unit.
Please refer to the boiler operating manual for further information on the above.
In addition the thermostatic valves on the boiler cooling coil and water dump devices
may have been activated depending on the type of fault or if a power interruption has
occurred.
