Honeywell 7800 Series Manual page 14

CR7890B 7800 SERIES INTEGRATED BURNER CONTROL
Procedure for Zero Meter Reading
If you cannot obtain a meter reading, replace the CR7890.
IMPORTANT
At the completion of Troubleshooting, be sure to
perform the Adjustments and Checkout procedures.
WARNING
Electrical Shock Hazard.
Can cause serious injury or death.
Open the master switch to disconnect power before
removing or installing the CR7890 or its cover. More
than one disconnect may be involved.
Fault Code
Code 11 Low ac line voltage
*Low AC Line detected.
Voltage*
Code 12 Excessive noise or device
*AC Quality running on slow, fast, or ac
Problem* line dropout detected.
Code 21 Flame sensed when no
*Unexpected Flame flame is expected during
Signal* STANDBY or PURGE.
Code 22 No-flame time present at
*Flame Signal the end of the Pilot Flame
Absent* Establishing Period; lost
during the Main Flame
Establishing Period or
during Run.
Code 23 Flame signal value is too
*Flame Signal high to be valid.
Overrange*
Code 42 Pilot (ignition) valve
*Wiring Problem/ terminal, Main valve,
Internal Fault* Ignition or Pilot Valve 2
was on when it should
have been off.
Code 43 Flame not sensed, or
*Flame Amplifier sensed when checked.
Problem*
Code 61 CR7890B self-test failure.
*Internal Faults*
65-0259—1
Table 7. CR7890B Fault Codes and Recommended Troubleshooting.
System Failure
1. Check the CR7890B and Keyboard Display Module connections.
2. Reset and sequence the CR7890B.
3. Check the power supply and make sure that frequency and voltage
4. Check the backup power supply, as appropriate.
1. Check that flame is not present in the combustion chamber; correct any
2. Check the wiring and correct any errors.
3. Reset and sequence the CR7890B.
4. If the fault persists, replace the CR7890B.
1. Measure the flame signal. If one exists, verify that it meets
2. Inspect the main fuel valve(s) and valve connection(s).
3. Verify that the fuel pressure is sufficient to supply fuel to the combustion
4. Check the CR7890B sighting position; reset and recycle. Measure the
5. If the fault persists, replace the CR7890B.
1. Reset and sequence the CR7890B.
2. Check the CR7890B sighting position; reset and recycle. Measure flame
3. If the fault persists, replace the CR7890B.
1. Remove system power and turn off fuel supply.
2. Check wiring, correct any errors.
3. Inspect Pilot Fuel Valve(s), both places, and connections.
4. Reset and sequence the CR7890B.
5. If the fault persists, replace the CR7890B.
1. Check wiring, correct any errors.
2. Reset and sequence the CR7890B.
3. If the fault persists, replace the CR7890B.
1. Reset and sequence the CR7890B.
2. If fault reappears, remove power from the CR7890B, reapply power,
3. If the fault persists, replace the CR7890B.
Fault Codes
In addition to the above checks, the CR7890B POWER LED
provides fault identification when the CR7890B locks out on
an alarm. Fault identification is a series of fast and slow
blinking LED lights. The fast blinks identify the tens portion of
the fault code (two fast blinks is 20) while the slow blinks
identify the units portion of the fault code (one slow blink is the
number one). Two fast blinks followed by one slow blink would
be fault code 21. This identifies a flame sensed during
STANDBY.
The LED code repeats as long as the fault exists. To clear the
fault, press the RESET button.
See Table 7 for a list of fault codes.
Recommended Troubleshooting
meet specifications.
errors.
specifications.
chamber. Inspect the connections to the fuel pressure switches. Make
sure they are functioning properly.
flame signal strength. Verify that it meets specifications.
strength. Verify that it meets specifications.
WARNING
Electrical Shock Hazard, Fire or Explosion Hazard.
Can cause serious injury, death or equipment damage.
Remove system power and turn off power supply.
then reset and sequence the CR7890B.
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