Q539 Subbases provide cooling anticipators, and mounting for T87F Thermostats. Q539 Subbases also provide system and fan switching for heating, cooling, and heating-cooling thermostats. For subbase specifications, refer to Tab Model:Q539 Page: 4 Model:Q539A Page: 20 Note: For opening this Honeywell Thermostat Q539 User Manual, your computer need Adobe Reader. You can get the Adobe … Continue reading Honeywell Thermostat Q539 User Manual