Dunkirk Q95M-200 Modulating Condensing Boiler - Manual (Page 16)

16
Boiler Not Firing And: Check For: Step Corrective Actions:
Control display blank
120 vac at terminals L1 and L2 of line
voltage strip?
1 NO - Check external line switch and fuse or breaker.
2
Determine if red light on line voltage monitor is flashing
indication fault. If there is fault verify input voltage dial
is properly set in accordance with steps in installation
manual. If fault does not clear after ten minutes replace
line monitor.
120 vac on both sides of fuse F1? 1
NO - Turn off power to boiler and replace fuse if
necessary. Inspect boiler interior wiring to determine
cause of fuse opening.
Wiring correct, in good condition, and
securely attached?
1
Correct if needed. Replace any damaged wiring or
components. Replace control module if problem persists.
Display first digit shows
0; last digits show 2 or
3-digit number (boiler
outlet water temp.)
Room thermostat and DHW aquastat
satisfied?
1
YES - Boiler off, no call for heat. Turn up thermostat or
aquastat. Boiler should start.
Thermostat or aquastat calling for heat
but boiler not firing.
1
Check voltage on both sides of low voltage fuse F3. (Turn
OFF external power before removing cover.) If necessary,
replace fuse. Determine reason for fuse failure if possible.
2
Check/set boiler parameters 2 and 3. Make sure space
heat or DHW is turned on. Turn on if necessary.
3
Turn off power to boiler. Temporarily jumper low voltage
terminal strip terminals T1 and T2 or DHW T1 and
DHW T2. Retry. If boiler operates, check CH and DHW
thermostat and wiring. Replace if necessary. Remove
temporary jumper(s).
4
Turn off power to boiler. Check wiring against wiring
diagram; verify all wiring in good condition and secure.
5 Replace wire harnesses and retry.
6 Replace control module.
Display first digit shows number from 1 to 8; last digits show 2 or
3-digit number (boiler outlet water temp.)
1 Boiler in normal operating mode.
Display flashes “9,” then “b.” Last two digits show code number. 1
See User Interface Quick Reference and Soft Lockout
Troubleshooting for more information on soft lockout code.
Display shows U 1.25
continuously
Transformer unplugged or not
functional
1 Plug transformer in.
2 Replace transformer.
F3 24V 4 Amp fuse is not functional 1 Replace fuse.
9 - TROUBLESHOOTING