LAARS LT Water ALL MODELS- Error 29

LAARS LT Water ALL MODELS- Error 29

LAARS LT Tankless Water Heater-ALL MODELS -LT199NXX1 / LT199PXX1
LT199NRX1 / LT199PRX1

Error 29-Condensate Trap Blocked. Hard Lock Out.
Press the power button on the display to clear the error codes.
1. Check condensate line and termination for blockages.
2. Check exhaust vent for blockages. 
 
AFTER ASSURING all of the above has been checked thoroughly and correct, please check SFN # of the circuit board (Part # ST1139) to assure that the correct revision is 1.02. (Power off the unit from the rocker switch and power unit back on allowing the unit to initialize WHILE looking at the display for the SFN#. 
If the revision (SFN #) is anything less than 1.02 (i.e. 1.01 ) then replace the circuit board with a KNOWN revision of 1.02.