1
69-0778—1
T4798S
Programmable Electric
Heat Thermostat
J. H. • Rev. 12-93 • ©Honeywell Inc. 1993 • Form Number 69-0778—1
TRADELINE
Application
The T4798S Programmable Electric Heat Thermostat
provides automatic line voltage control of electric resis-
tance heating equipment. The T4798S Thermostat senses
light and motion to choose the appropriate setpoint based on
four operating modes:
—Occupied-light
—Occupied-dark
—Unoccupied-light
—Unoccupied-dark
Thermostat has an adjustable light level threshold for
light sensing:
—most sensitive-dark
—less sensitive-dim
—least sensitive-light
Uses wide-angle passive infrared motion detection.
Thermostat retains programming during power failure.
Proportional, integral plus derivative microprocessor con-
trol provides accurate temperature control; triac-based
switching. The T4798S Thermostat can be used as a ther-
mometer; display can convert between Fahrenheit and
Celsius temperature. Allows easy two-wire installation.
Suitable for residential or commercial electric baseboard
heating applications. Not for use in central electric heating
systems or with inductive loads.
TEMPERATURE SETTING RANGE: 44
°
to 80
°
F [7
°
to
27
°
C].
PROPORTIONAL BAND (REGULATION): 0.9
°
F [0.5
°
C].
ELECTRICAL RATINGS:
Voltage/Frequency: 208 to 240 Vac, 50/60 Hz.
Power Rating:10.5A maximum (2200 to 2500W); non-
inductive resistive load.
Power Consumption (Off): 560 mW.
WIRING CONNECTIONS:
Two 6 in. [150 mm] copper leadwires (suitable for con-
necting to aluminum wiring if approved CO/ALR
connectors are used).
APPROVALS:
Underwriters Laboratories Listed: File No. E136167,
Guide No. XAPX.
Canadian Standards Association Certified: File No.
LR91801-1.
Canadian Standards Association Performance Certified:
Standard C273.4A.
Installation
WHEN INSTALLING THIS PRODUCT...
1. Read these instructions carefully. Failure to fol-
low these instructions could damage the product or cause a
hazardous condition.
2. Check the ratings on the product to make sure the
product is suitable for your application.
3. Installer must be a trained, experienced service
technician.
4. After installation is complete, check out product
operation as provided in these Instructions.
WARNING
HIGH VOLTAGE CONTROL.
ELECTRICAL SHOCK HAZARD.
Follow local codes and ordinances when install-
ing this thermostat. Improper handling may cause
serious injury or death.
CAUTION
1. Disconnect power supply to prevent electrical
shock or equipment damage.
2. If connecting with aluminum conductors, use
CO/ALR solderless wire connectors to avoid
fire hazard.
3. Keep the air vents on both the top and the
bottom of the thermostat clean and free from
obstructions to prevent overheating of the unit.
IMPORTANT: Do not use this thermostat with central
electric heating systems, or fan-forced heaters.
LOCATION
Mount this thermostat on a vertical outlet box. Install a
vertical outlet box about 5 ft [1.5m] above the floor in an
area with good air circulation at room temperature.
Do not install the thermostat where it can be affected by:
— drafts or dead spots behind doors, in corners or under
cabinets.
— hot air from convectors.
— radiant heat from sun or appliances.
— concealed pipes and chimneys.
— unheated (uncooled) areas such as an uninsulated
outside wall behind the thermostat.
!
!
This equipment is a Class B digital apparatus which com-
plies with Canadian Radio Interference Regulations, CRC
c.1374.
