LAARS NeoTherm NTV (Sizes 399-850 MBTU/h) - Service Manual - Manual (Page 27)

17
Service Manual - NeoTherm 500
Checking the Safety Chain - continued
B3
cont.
24V AC is
present?
(other safety
switches closed)
Yes
No
Check for 24V AC at
terminal J6-1.
With boiler attempting to run,
check for 24V AC across
two leads on air pressure switch.
24V AC is
present?
(switch open)
Yes
See procedure B16 -
“Checking Condensate Trap Level Switch”
No
12185
See procedure B19 -
“Checking the Air Pressure Switch”
NT unit should be trying to fire.
If not firing, control panel should
be displaying an error code.
See Error Codes in Appendix.
2-12