Installer setup (ISU) (continued)
ISU Setup Number and Description
303 = Auto Changeover Differential
340 = Backup Heat Droop
(TH3210U only)
350 = Upstage Timer to Backup Heat
(TH3210U only)
365 = Compressor Cycle Rate (Stage 1)
370 = Heating Cycle Rate (Stage 1)
375 = Heating Cycle Rate Auxiliary Heat
(TH3210U only)
387 = Compressor Protection
Options (factory default in bold)
0 °F to 5 °F
0 °C to 2.5 °C
Note: Differential is NOT deadband. Differential means how far past the
setpoint before switching to the mode selected. Deadband setup is not
an option. An advanced algorithm fixes the deadband at 0 °F. This is
more advanced than previous thermostats.
0 = Comfort
2 = 2 °F
3 = 3 °F
4 = 4 °F
5 = 5 °F
6 = 6 °F
7 = 7 °F
8 = 8 °F
0 = Off
1 = 30 minutes
2 = 45 minutes
3 = 60 minutes
4 = 75 minutes
1 - 6
Note: This ISU is only displayed when Cool /Compressor Stage is set to
1 stage. Cycle rate limits the maximum number of times the system can
cycle in a 1 hour period measured at a 50% load. For example, when
set to 3 CPH, at a 50% load, the most the system will cycle is 3 times
per hour (10 minutes on, 10 minutes off). The system cycles less often
when load conditions are less than or greater than a 50% load.
1 - 12
Note: This ISU is only displayed when Heat Stage is set to 1 stage. Cycle
rate limits the maximum number of times the system can cycle in a 1
hour period measured at a 50% load. For example, when set to 3 CPH,
at a 50% load, the most the system will cycle is 3 times per hour (10
minutes on, 10 minutes off). The system cycles less often when load
conditions are less than or greater than a 50% load. The recommended
(default) cycle rate settings are below for each heating equipment type:
Standard Efficiency Gas Forced Air = 5 CPH; High Efficiency Gas Forced
Air = 3 CPH; Oil Forced Air = 5 CPH; Electric Forced Air = 9 CPH; Fan Coil
= 3 CPH; Hot Water Radiant Heat = 3 CPH; Steam = 1 CPH.
1 - 12
0 = Off
1 - 5 minutes
Note: The thermostat has a built in compressor protection (minimum
off timer) that prevents the compressor from restarting too early after
a shutdown. The minimum-off timer is activated after the compressor
turns off. If there is a call during the minimum-off timer, the thermostat
shows "Wait" in the display. This ISU is displayed if ISU 220 is set to at
least 1 stage.
8
9 = 9 °F
10 = 10 °F
11 = 11 °F
12 = 12 °F
13 = 13 °F
14 = 14 °F
15 = 15 °F
5 = 90 minutes
6 = 2 hours
7 = 3 hours
8 = 4 hours
10 = 5 hours