Hofully someone can point me in the right direction here...
I have a recently acquired a 2003 550X spa and was aware that there was, and still is, an issue where it shuts down and reads 'OH'.
There doesn't seem to be much of a pattern to this occurring but its fair to extremely consistent.
Initially the spa heats up to anywhere around 34 with no issue at all, then cuts out. Re-sets straight away and continues to heat a little more (display set to 38).
I can get the spa to full temp by resetting each time but then it seems to shut down more frequently.
I initially replaced the hush pump - This was needed for more than one reason.
I believe the original owner tried replacing both temp sensors.
And I have checked for air blockages and the filter is new.
Any help with what to try next would be much appreciated!
One thought... can I test or possibly clean the flow switch easily? Is that worth trying?