LAARS NeoTherm NTV (Sizes 150–285 MBTU/h) - Service Manual - Manual (Page 50)

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Service Manual NeoTherm 80 - NeoTherm 285
High Stack Temperature Fault
B20
Yes
No
Correct this immediately.
Blocked exhaust outlet?
Dirty heat exchanger?
If you have the current user interface,
set the stack temperature limit to 190°F.
Actual stack
temperature
problem?
Check the continuity on the wires from
the sensor to J9-4, J9-5, and J9-6 on the
control module.
Wiring to
sensor is correct? Good
connections?
No
Yes
Fault disappears?
No
Replace the control module.
Replace the sensor.
See Section B34
Problem
with circulator
pump?
Yes
No