10 Water Level Control
Mk8 MM Manual Page | 199
10.10.3 Test Outputs and Shunt Switch
The test input terminal TST can be used to check the auxiliary alarm outputs or the shunt switch operation
when the burner is firing. The table below shows the expansion options for the test input.
Shunt switch – time to 1
st
low
Shunt switch – time to 2
nd
low
When the test input is set for auxiliary alarm outputs checks, hold the test input continuously to cycle through
the alarm outputs every two seconds.
For shunt switch test, there is time delay for the burner to reach 1
st
low set in expansion option 22, allowing
the operator to decrease the water level to check the 1
st
low alarm. If the water does not drop to 1
st
low within
this time, the shunt switch test will be cancelled, and the MM will revert to normal operation. There is
additional delay set in expansion option 23 to allow the operator to decrease the water to 2
nd
low to check
the 2
nd
low alarm. If the water level does not drop in this time, the MM will leave shunt switch mode and the
burner will turn off.
A timer is displayed on the screen when doing these tests as shown below. After reaching 2
nd
low, if the
water level does not rise to control point within 10 minutes, alarms will be triggered.
The alarm outputs and shunt switch can also be checked via the Water Level Status screen on the MM.
Figure 10.10.3.i Trigger Shunt Switch
Press to cycle the alarm outputs every 2 seconds. Press to check the water level
alarms as described above.
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