Product Troubleshooting

FIVE FLASHES - TROUBLESHOOTING CODES
• Twin communications fault
• Occurs if the 24 VAC supply to the twins are not in phase with each
other, or power is removed from one of the twins.
• While a Twin Fault exists, the control does not respond to
thermostat commands and flashes "5" on the status LED. Open
limit and undesired flame response are still operational. The
control continually tries to establish communication and
automatically resumes normal operation when communication is
re-established. If a twin fault occurs during a heat cycle, both
furnaces terminate the call for heat immediately. The only chance
for blower mis-synchronization is if the blower off delays are set
differently on the twins. If a twin fault occurs during high speed fan
or continuous fan, both controls shut blowers off immediately.
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