Fault Finding; Figure 9.2 Water Flow Switch - Hamworthy F40V Installation, Commissioning And Operating Instructions

9.0 FAULT FINDING

The Fleet boiler is equipped with full self-diagnostic fault indication, with faults allocated a code, which is
displayed (flashes) on the display - refer to section 8.3.9 - Maintenance functions.
The common fault codes are detailed in section 8.3.9 - Maintenance functions.. Fault codes not detailed in this
manual should only be investigated by an Engineer.
Should a fault code appear which cannot be reset, or a fault code repeatedly occurs,
contact Hamworthy Heating for assistance. Do not continue to operate or use the boiler
as this may cause damage to the controls.
9.1 Safety Temperature Limiter (Limit Thermostat)
1. The electronic control thermostat has several safety levels built in such that a controlled shutdown should occur
before the safety temperature limiter is activated. Should these safety levels be overridden (say external pump
overrun failure after shutdown) the safety temperature limiter will trip initiating a boiler shutdown, preventing the
boiler from firing. The code (110) on the controls display will flash indicating that the safety temperature limiter has
tripped.
2. The safety temperature limiter is auto reset located on the top rear of the heat exchanger block. Once the
boiler has cooled to normal operating temperature, pushing the reset pushbutton on the display (refer to section
8.1.1 - Controls Operation) will reset the lockout. Should the lockout code not extinguish and the boiler does not
fire up, it is possible that the safety temperature limiter will not reset because the boiler is still too hot.
3. Always carry out an investigation to ascertain the reason for overheating. The most common cause of
overheating is lack of water flow rate through the boiler possibly caused by a faulty pump or blockage in the heat
exchanger circuit due to system debris.
9.2 Water Flow Switch
1. The water flow switch is located in the return pipe
before the pump (see figure 9.2) and will prevent the
boiler from firing should there be inadequate or no water
flow. This is to protect the heat exchanger from damage
in the absence of water (dry firing) which will cause cata-
strophic failure of the heat exchanger.
2. The operation of the flow switch can be checked by
closing one of the isolating valves connecting the boiler
to the system., this will generate error E164 on the LMU
display.
Figure 9.2 - Water Flow Switch
9.3 Ignition Controller
1. The flame is under constant supervision by the burner ignition controller. The controller monitors the flame's
ability to rectify an AC current. If the flame diminishes for whatever reason and the rectified current drops below
the controller's minimum detection current (3µA DC), the controller will de-energise the gas control valve within 1
second and commence a restart. Failure to establish and detect a flame during the light-up sequence will result in
burner shutdown and lockout within 5 seconds, requiring a manual reset to restart the ignition sequence. Refer to
section 8.3.9—Maintenance functions..
2. If the boiler continues to lockout, then an investigation must be made to ascertain the cause. Refer to figure
8.3.10 - Operating faults, for possible causes of lockout.
3. A false flame signal at the start and during pre-purge will cause the boiler module to restart its ignition se-
quence at the end of the pre-purge period. If this occurs 3 times in succession the controls will disable operation
of the boiler module, requiring reset of the module. Refer to section 8.3.10 - Operating faults
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HAMWORTHY HEATING LTD FLEET V series 500001213/G