I have a Bosch SM036 water geothermal HVAC system. The configuration is open loop with incoming well water that discharges downhill into a pond. This past week the weather was very windy and sub-zero and the discharge line apparently froze. The back pressure in the line caused a compression fitting in the discharge line located above the basement ceiling to fail and the unit kept running and flooded my basement. My question is does the unit have an automatic feature that will shut it down when it reaches a certain threshold of back pressure in the discharge line? If so, could it be that the compression fitting blew out before the unit reached that threshold? I will direct my HVAC guy to run a new line that has no compression fittings at all in the ceiling, but I'm concerned that it could happen again.