Dunkirk 95M-200 Control Manual And Troubleshooting Manual page 17

SOFT LOCKOUT (Display fl ashes "9" and then "b" in fi rst position; last two digits on steady (code))
Code Reason For Soft Lockout
0.14" Pressure switch contacts
08
open
High Limit Operation: Burner
18 off until outlet water temperature
drops below 180 °F
High Limit Operation: Burner
19 off until return water temp. drops
below 190 °F
High Limit Operation: Return
24
temp. is higher than supply temp.
High limit operation: Outlet
water temp. increased too quickly.
25
Non-adjustable default setting
9.8°F/sec
Aquastat contacts open
or
26 LWCO contacts open
or
3.5" Switch open
9 - TROUBLESHOOTING
Corrective Actions (pressing RESET should restart boiler immediately):
Check pressure switch for proper operation. Replace pressure switch if moisture has
1
entered switch. Check venting for blockage. Clear if present.
Happen when heat demand is lower than lowest fi ring rate of boiler, such as
operation of single, small zone. Check system for:
• Verify boiler and system are full of water.
1
• Verify system does not have trapped air.
• Inspect and verify system piping and components.
• Verify piping agrees with boiler manual recommendations.
Use contact thermometer to check outlet water temp. Compare to temperature
shown with display in "INFO" mode ("1" in fi rst digit). Replace return temperature
2
sensor if results are not close. Replace control module if sensor replacement doesn't
solve problem.
Check system for:
• Verify boiler and system are full of water.
• Verify system does not have trapped air.
1
• Inspect and verify system piping and components.
• Verify water fl ow is not reversed or pipes crossed.
Use contact thermometer to check return water temp. Compare to temperature
shown with display in "INFO" mode ("2" in fi rst digit). Replace return temperature
2
sensor if results are not close. Replace control module if sensor replacement doesn't
solve problem.
• Verify boiler and system are full of water.
• Verify system does not have trapped air.
1
• Inspect and verify system piping and components.
• Verify water fl ow is not reversed or pipes crossed.
Use contact thermometer to check return water temp. Compare to temperature
shown with display in "INFO" mode ("2" in fi rst digit). Replace return temp. sensor
2
if results are not close. Replace control module if sensor replacement doesn't solve
problem.
Indicates fl ow rate too low. Check system for:
• Verify boiler and system are full of water.
1 • Make sure system does not have trapped air.
• Inspect and verify system piping and components.
• Verify piping agrees with boiler manual recommendations.
Verify operation of boiler circulator:
• Check voltage at circulator junction box to ensure 120 vac when boiler
operates. If no voltage, check wiring and wiring connections.
• High voltage terminal strip terminals 5 and 6 should show 120 vac for space
2
heating; terminals 3 and 4 should show 120 vac for DHW. Replace circulator if
powered but not operating.
• Replace line voltage wire harness if necessary. Replace control module if wire
replacement doesn't resolve.
Verify proper setting of control.
1
Water temp too high, wait for temperature to drop below 180 degrees.
Check water level in boiler, fi ll if low.
Press LWCO reset switch on display panel
2
If problem still exists, check LWCO probe and board according to manufacturer's
instructions. Replace if necessary.
Check pressure switch for proper operation. Replace if moisture has entered switch.
3
Check venting for blockage. Clear if present.
17