Dunkirk Q95M-200 Modulating Condensing Boiler - Manual (Page 13)

13
Troubleshooting Tools
Tools needed for troubleshooting your boiler:
• Voltmeter that can check 120 VAC, 24 VAC, and 12
VDC
• Continuity Tester
• Contact Thermometer
• Inclined Manometer or Pressure Gauge with 0-6.0”
range (0.01” scale) for measuring suction pressures at
pressure switch
• U-Tube Manometer or Differential Pressure Gauge
with 0-14” range (0.1” scale) for measuring inlet and
manifold gas pressures
Initial Service Checks
Prior to troubleshooting:
1. Verify circuit breaker is ON or fuse is okay at electrical
panel.
2. Verify service switch is ON.
3. Verify 120 VAC (minimum 102 VAC to maximum 132
VAC) to boiler.
4. Verify thermostat is calling for heat and contacts
(including appropriate zone controls) are closed. Check
for 24 VAC between thermostat wire nuts and ground.
5. Verify all external limit controls are either installed (and
closed) or temporarily jumpered for testing.
6. Verify gas is ON at gas meter, at all appropriate manual
shutoff valves, and at gas control valve. Gas pressures
should be maximum of 10” w.c. (natural gas) or 14”
w.c. (for LP gas) with no flow (lockup) or with boiler on
and minimum of 5” w.c. with gas flowing (verify during
boiler startup with boiler at high fire).
7. Verify wire connectors at boiler control and at
originating control are securely plugged in or
connected.
8. Verify all hoses are securely connected and are not
plugged in or damaged.
8 - SERVICE HINTS
WARNING
Fire, Explosion, Shock Hazard. Revision,
modification, substitution or elimination of factory
equipped, supplied or specified components could
result in death or serious injury.
!
Important Service Information
• If any component does not function properly, make
sure it is correctly installed and wired before replacing
it.
• Static electricity discharge can damage the integrated
modulating boiler control (IMBC). Touch metal surface
to discharge static electricity before touching control.
• Boiler control cannot be repaired. If it malfunctions it
must be replaced.
• Only trained, experienced service technicians should
service boiler control systems.
• After troubleshooting, follow “Detailed Sequence of
Operation” Section 7 page 12, for normal light off
procedure.
• All controls are factory tested,a defective control is
generally least likely cause. If you suspect you have a
defective boiler control, read “Troubleshooting” Section
9 before you replace it.
• It is unlikely that two consecutive controls are
defective. Chances are that either there is nothing
wrong with the control or it is damaged by some other
problem (for example, an electrical short burning out a
transformer).