B7 - high water temperature limit switch, B8 - checking the flow switch, High water temperature limit switch – LAARS NeoTherm NTV (Sizes 150–285 MBTU/h) - Service Manual User Manual
Page 32: Checking the flow switch, See procedure b8, B7 b8, High water temperature limit switch (optional), Checking the flow switch (optional)
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Service Manual NeoTherm 80 - NeoTherm 285
High Water Temperature Limit Switch (optional)
Laars does not provide this switch. It is installed only where required.
This is a normally-closed (NC) switch. If the water temperature rises
above the pre-set limit, the switch opens.
Some types of switches must be reset manually. To reset this type of
switch, press the button on the control. Other switches will reset auto-
matically.
Correct the cause of the problem and/or replace the switch.
Checking the Flow Switch (optional)
B7
B8
Flow present?
No
Yes
Check for line voltage at the circulator pump
terminals 1-2 on TB5.
Momentarily jump switch
(TB8-6 to TB4-1)
Boiler fires?
Yes
Replace switch.
Check for actual water flow.
Circulator pump running?
No
Warning!
Do not leave the room while unit is
operating with the flow switch bypassed.
Remove the jumper as soon as the test is
complete.