TQ DGH - FC8, FC17 and FC18 Condensate detected
Fault code history can be accessed:
SETTINGS/SERVICE/GAS HEATER 01/7378 CONT/FAULT LOG
YouTube Video - MagIQtouch Heater Fault Log
If the FC18 issue still persists after confirming that the unit is level, there are no blockages in the condensate pressure switch hoses, and the unit is draining correctly, try replacing the condensate pressure switch (Part #639826). Over time, the microswitch on the 18pa pressure switch, despite sounding operational, may have contamination on its electrical contacts, causing sticking issues.
Check the silicon tube from condensate pressure switch to the condensate drain tray isn't excessive in length to create a low
point that can cause condensate to block to tube and trigger a FC18
Below image shows an incorrect routing of the silicon tube
Check the silicon tube from condensate pressure switch to the condensate drain tray isn't excessive in length to create a low
point that can cause condensate to block to tube and trigger a FC18
Below image shows is the correct routing of the silicon tube
Check the small breather hole on the pressure switch 18 Pa (for condensate) circled in red below is clear and is not covered by silicon/rubber pressure switch hose. This hole must not be blocked or covered!!!
If the FC18 issue still persists after confirming that the unit is level, there are no blockages in the condensate pressure switch hoses, and the unit is draining correctly, try replacing the condensate pressure switch (Part #639826). Over time, the microswitch on the 18pa pressure switch, despite sounding operational, may have contamination on its electrical contacts, causing sticking issues.