LAARS NeoTherm NTV (Sizes 150–285 MBTU/h) - Service Manual - Manual (Page 34)

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Service Manual NeoTherm 80 - NeoTherm 285
Removing and Replacing the Flow Switch
The switch assembly includes two parts: a set of paddles
that extend into the water pipe, and a control box. See
Fig. B10-1.
Figure B10-2 shows the paddles that extend into the pip-
ing to detect the water flow.
The paddles are sized to match the amount of water
flowing through the system, so a flow switch installed in
a smaller system, with a smaller pipe, will have smaller
paddles, and a switch in a larger system will have larger
paddles. Keep this in mind if you need to replace one of
these switches.
Tools and equipment required:
• Medium-sized pipe wrench
• Sheet-metal shears - use a type that can make a
curved cut
• 100-grit sandpaper
• Pipe dope or Teflon® tape
Procedure:
1. Turn off power to the system. Use the main discon-
nect switch mounted above the front panel.
2. Isolate the boiler. Turn off the water shutoff valves
located upstream and downstream of the unit.
3. Drain the boiler. The drain valve is located near the
lower end of the heat exchanger.
4. Remove the cover from the control box for the
switch. Note the positions of the wiring connec-
tions, then disconnect the wires.
Fig. B10-1 - Flow switch installation (typical)
Fig. B10-2 - Metal paddles used to detect water flow
(typical)
B10