Just talked to Master Flow and they said it wouldn't work with the older SLRT1 Model, but it would work on the newer SLRHT1 Model which is newer, cheaper, and controls humidity and temperature.
This is for use with Master Flow Solar Attic Fans only. Only for use with the 24 volt motor. If you have any other inquiries about our Master Flow products please call Technical Services at 800-211-9612.
Thank you for contacting MasterFlow ... The PT6 thermostat is designed to operate one device. Please call Technical Services Group at 800-211-9612.
Thank you for contacting MasterFlow ... We recommend a humidity setting of 70%. The 60% setting may be causing the device to operate longer than desired. When set at 60%, the fan will operate until the attic humidity is below 60%. Please call Technical Services at 800-211-9612, M-F 8A-5P ET, with any additional questions.