10 Water Level Control
Mk8 MM Manual Page | 196
10.9.9 Operational Checks
Once the capacitance probes/external level sensor have been commissioned, the water level operation must
be checked for safety and alarms, then the burner can be commissioned, and the water level probes re-
commissioned when there is heat in the boiler.
• Water level operation must be checked after commissioning or after modification of any setups.
These operational checks are for boilers without a shunt switch, see section 3.10.3 for shunt switch.
• Set the system to RUN mode and allow the burner to fire. With the boiler supplying steam at a
steady rate check that the water level is maintained at the control point for modulating control. For
on/off control, check that the boiler feed water pump turns on and off appropriately at the
commissioned points. Ensure that all audible and visual alarm indicators are inactive.
• Reduce the level of the water (by blowdown or other suitable means), check that a 1st low alarm
occurs, and the burner stops firing when the water level is just below the commissioned 1st low level.
• Ensure that the 1st low audible and visual indicators are active. If fitted, press the external
mute/reset button and check that the audible alarm is muted.
• Reduce the level of the water further and check that the 2nd low alarm is displayed when the water
level is just below the commissioned 2nd low level; the burner should remain off.
• Ensure that the 2nd low audible and visual indicators are active. If fitted, press the external
mute/reset button and check that the audible alarm is muted.
• All 1st Low/2nd low alarm conditions must be cleared before proceeding to test the high water. To
test high water, it is necessary to increase the water level to just above that of the commissioned
high water position. If there is no means to manually increase the level of the water, it is possible to
select Water Level Commission mode and increase the level of the water manually. The MM can
then be restarted by de-selecting and re-selecting the fuel. The unit will restart in RUN mode and
should report a high water alarm. Check the burner operation runs or stops according to expansion
option 9.
• Ensure that the high water audible and visual indicators are active. If fitted, press the external
mute/reset button to check that the audible alarm is muted.
• Check the operation of the TB output terminal if using a contactor with solenoid valve.
• Once the water level control has passed these operational checks, the burner can now be
commissioned with a fuel to air curve, after which the probes are re-commissioned at boiler
pressure.
Note: All local & national codes for safe operation of boiler plant must be adhered to. If in any doubt
contact your local specialist authority.
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