Light Commercial Thermidistat Accessory

LIGHT COMMERCIAL

THERMIDISTAT ACCESSORY

General — A Light Commercial Thermidistat Accessory (part number TSTATCCPLH01-B) or PremierLink™ control- ler with humidistat is required for each unit for field installation to control the energy recovery section. See Fig. 13.

The Light Commercial Thermidistat is a 7-day programma- ble, wall-mounted, low-voltage control which combines tem- perature and humidity control in a single unit. It provides separate set points for heating and cooling, and adds dehumidi- fication with separate set points for occupied and unoccupied periods. Different heating and cooling set points and times are programmable for up to 4 periods per day and 7 days per week. The dehumidification output provides direct control of humidity. During power loss an internal memory stores pro- grams and settings for unlimited time, and the clock continues to run for at least 8 hours. Batteries are not used.

Power — Note that this control does not require batteries and is not “power stealing.” It does require 24 vac (R and C terminals) from the RTU’s low-voltage transformer to be con- nected to it for proper operation. The control will not operate without these 2 connections. See Fig. 14.

Dehumidification Equipment and Connec- tions — The dehumidification output terminals on the Light Commercial Thermidistat must be connected to the dehumidify input terminals on the energy recovery section. Additionally, if the RTU is equipped with optional MoistureMi$er™ Dehumid- ification accessory, a relay in the energy recovery section energizes the MoistureMi$er solenoid to activate the enhanced dehumidification mode.

Step 1 — Select Light Commercial Thermidis- tat Location — Light Commercial Thermidistat should be

mounted:

•Approximately 5 ft (1.5 m) from floor.

•Close to or in a frequently used room, preferably on an inside partitioning wall.

•On a section of wall without pipes or ductwork.

The Light Commercial Thermidistat should NOT be mounted:

•Close to a window, on an outside wall, or next to a door leading to the outside.

•Exposed to direct light and heat from a lamp, sun, fire- place, or other temperature-radiating object that may cause a false reading.

•Close to or in direct airflow from supply registers and return-air registers.

•In areas with poor air circulation, such as behind a door or in an alcove.

HEIGHT (in.)	WIDTH (in.)	DEPTH (in.)
41/4	71/2	13/8

Fig. 13 — Light Commercial

Thermidistat Accessory

FOR MOISTUREMI$ER UNITS ONLY

LIGHT

COMMERCIAL

THERMIDISTAT

ACCESSORY

OPTIONAL

HUMIDISTAT (HL38MG029)

Fig. 14 — Light Commercial Thermidistat

Accessory Low-Voltage Connections

Step 2 — Set DIP Switches — There is a 4-section DIP switch within the Light Commercial Thermidistat which must be properly set by the installer. It is easiest to set these 4 switches before the Light Commercial Thermidistat is mounted to the wall, so complete the following steps first:

1.Open hinged Light Commercial Thermidistat cover.

2.Remove cover completely by gently snapping it apart at the hinge.

3.Switches are located in upper right corner of circuit board. To change switch position, use corner of a small screwdriver to slide switch to opposite position.

4.After switches have been set, do not reassemble the 2 halves. The rear plastic will be first mounted to wall.

SWITCH 1 — Not used SWITCH 2 — Not used

SWITCH 3 — SMART/CONVENTIONAL RECOVERY — Selects between conventional or smart recovery from setback. Conventional recovery changes to new set point at prepro- grammed time. Smart recovery, which is active in both heating and cooling, starts selected cycle 90 minutes earlier and smoothly adjusts set point so room will arrive at programmed temperature at programmed time.

NOTE: The occupied output is only energized at the prepro- grammed time.

To Set:

OFF — for smart recovery. This is factory default. ON — for conventional recovery.

SWITCH 4 — INSTALLER TEST OFF/ON — Selects a special installer test mode that assists with checkout and troubleshooting. See Step 5 — Conduct Light Commercial Thermidistat Start-Up and Checkout.

To Set:

OFF — for normal operation. (Factory default setting.) ON — for Installer Test mode.