On arrival, tech found no standing water in crawlspace, but on any spots with missing moisture barrier, the ground was packed mud. Moist mud. Not wet mud. Dehumidifier was running with evaporator frozen. Tested drain and found it clear. Set up 3 psychrometers and found an average of 67% RH in crawlspace. Foundation vents are properly sealed. There is visable light shining between brick foundation and wooden walls. This was documented on November 19th. Tech melted ice from evaporator coil and started dehumidifier back up without media filter. Prefilter only to increase airflow and prevent freezing. Turned humidistat down slightly to perhaps reduce length of run cycles and prevent coil freezing. Allowed dehumidifier to run 20 minutes and measured about a 5% reduction in RH in that time. Spoke to Adam and let it run an additional 15 minutes. Verified drain is dripping steadily. RH in crawlspace is currently hovering around 60%.