Don’t know if you can help a complicated situation, but possibly simple problem
Bought a second hand baxi 120 instant boiler, natural gas. Exported to Portugal, converted to propane using genuine baxi spare part. Fired up, went through ignition sequence OK, but and would not register flame and switched off.
OK bought new thermocouple then new board. Switched on, ran ok, and switched off to double check connections. That’s it, never even started again, always going straight into lockout when switching on
Started some fault finding with help from board manufacture.
Tested earth to neutral as the supply in Portugal is unearthed as overhead supply. So whole house is floating with no earth, but current out of balance breaker for safety
Found polarity was reversed due to non-polarised plug used for temp connection so neutral was 180 v above earth.
Sorted that out as manufacture said the board baxi use is very earth voltage sensitive. not more than 1.7volts. Even attached temp earth stake direct to boiler
But that board never went again even when installed grounded earth direct to boiler. So scraped that and have bought another board
Sorry to be so long winded but as I say complicated situation.
First no flame detect, new board, and then it locks out instant it’s switched on, though it did run ok just once
The crutch of the matter I don’t want to fit new board and blow that. How critical is the earth on baxi instant boiler, obvaseliy for safety better earthed. But purely from the point of operation. Contacted baxi UK for advice but would not comment due to not having corgi no
With no earth stake or earth connection supplied by Portuguese supply and on solid rock will take some fixing.
Earth and neutral now have voltage difference of. 0.7 volt, even without earth stake