LAARS NeoTherm NTV (Sizes 150–285 MBTU/h) - Service Manual - Manual (Page 26)

16
Service Manual NeoTherm 80 - NeoTherm 285
Checking the Safety Interlocks
B3
24V AC is
present?
(all switches closed)
Yes
No
Safety interlock chain is OK
Check for 24V AC between
TB8-1 and TB4-1.
Check for 24V AC between
TB8-2 and TB4-1.
24V AC is
present?
Yes
See procedure B4 -
“Checking the Low Water Cutoff Switch”
No
Check for 24V AC between
TB8-4 and TB4-1.
24V AC is
present?
Yes
Check the optional external
high limit switch:
1. Check for actual high outlet
temp. condition (manual reset)
2. Check temp. setting on switch
3. Replace switch No
Check for 24V AC between
TB8-6 and TB4-1.
24V AC is
present?
No
See procedure B8 -
“Checking the Flow Switch”
Yes
Continued