Version 1.4
90 NCB-E Service Manual
Scenario2
Check the flame rod
Power OFF the unit
Check connector
Check that gas valve is open or
check LP supply
Check the voltage between #1 and #2 of CN 16:
22-24 VDC
Check the voltage between #1 and #3 of CON 4:
22-24 VDC
(see page 18 for Wiring Diagram)
In case of LP gas model, low gas pressure can cause
“Ignition Failure”.
* Normal gas pressure: 8.0 - 13.5" w. c.
NO
NO
NO
Yes
Yes
Yes
Is gas valve operating
normally?
Does the main
gas valve have proper
voltage?
Is gas valve open?
Scenario3
Access the Service Information Display to
check Item (K) for Flame State (see Page 44)
Restart unit
Check connector
(#1 of CN2)
Clean or replace the flame rod
Check whether ground circuit is
properly installed.
Check the current #1 of CN 2: DC 1 - 20μA
(see page 60 for Wiring Diagram)
NO
NO
Yes
Yes
Is the flame detection
device normally
operating?
Is the flame current
detected?
