I've got two Liebert Challenger 3000's and a MiniMate 1-ton.
All three units exibit the following behaviour when the outdoor ambient goes up close to about 60-65... The humidity level goes up past the setpoint, making the unit go into dehumidification mode. It stays in this mode until the temp drops the below temp. setpoint & the room is too cold. Apparently the re-heat is not working or not turned on.
These units don't have any fresh-air intake; how is the level of humidity so greatly correlated to the OD ambient? Our building is not full of holes; its well-insulated.
Then, to maintain the temperature setpoint, I end up raising the humidity setpoint to match ambient humidity - at least it allows the compressor to shut off. A third Challenger 3000 does <b>not</b> exibit this behaviour; it maintains temp & humidity just fine no matter what the OD ambient.
Are these units in bad need of sensor calibration, or should the senors be replaced?