THX9321 & THX9421 Product Data

THX9321 PRESTIGE
®
2.0 AND THX9421 PRESTIGE
®
IAQ WITH EIM
68-0311—02 88
7. Delta T Diagnostics is only for non-zoned forced air
systems.
8. The thermostat does not provide Heat or Cool Delta T
Diagnostics when it is set to control an Economizer
module (ISU 2220).
9. The thermostat cannot be setup for Heat Delta T
Diagnostics when the thermostat is used with an external
fossil fuel kit (ISU 2190).
Setting up Alerts and Diagnostics
1. Set up the Return and Discharge Air Sensors by
selecting the check boxes on the screen. These sensors
are used to measure Delta T.
Fig. 148.
2. Select the terminals that are wired to the Discharge and
Return Air Sensors (terminals S1, S2, S3, or S4 at the
EIM).
IMPORTANT
Be sure to select the correct terminals for the dis-
charge and return air sensors. For example, if the
return air sensor is wired to S1, select S1 (see Fig.
149) for the return air sensor.
Fig. 149.
3. Select the Discharge and Return Air Sensor Type (10K).
IMPORTANT
10K sensors must be used for Delta T Diagnostics.
Fig. 150.
4. Turn on the Heat and Cool Delta T Diagnostics. Default
is On.
Fig. 151.
Fig. 152.