I’ve never heard of “HTL”, but I’m certainly impressed that
”.... The factory flew out a technician to Panama to replace the control modules and they worked for a couple of days then failed again. We have had other marine air con. technicians work on them in New Zealand and Singapore as well ...”
Less impressive is the persistence of you’re A/C problem.
What exactly do you mean by "Control Module" ? Is this the Pump
Relay, usually mounted on/near the A/C Unit, or the Wall Mounted Ambient Temperature Control (Thermostat) ?
What explanation does the factory offer?
High Heat & Low Voltage are probably the two most common causes of "Controls" (especially electronic) failures.
Regards, & good luck,