1 68-0063—3
J. H. • Rev. 6-95 • ©Honeywell Inc. 1995
L8104A,B,C,D
Electronic Water
Heater Controllers
The L8104A,B,C,D Electronic Controllers pro-
vide temperature control and ECO limit action for
gas water heaters.
L8104B with
Potentiometer
Remote
Potentiometer
Sensing
Bulb
■ L8104A,B are used in standing pilot and electronic
ignition systems.
■ L8104C,D are used only in electronic ignition sys-
tems.
■ Includes electronic module, one or two sensing bulbs,
and setpoint potentiometer (remote- or board-
mounted).
■ Sensing bulb contains thermistor sensor and ECO
switch. Second bulb in L8104B,C contains ther-
mistor only.
■ L8104A has single sensing bulb.
■ L8104B has two sensing bulbs available with upper
and lower bulb sensing authority allocated in ratios
of 1:1, 2:1, 3:1, and 4:1. Two sensing bulbs provide
temperature averaging.
■ L8104C has two sensing bulbs and manual reset
pushbutton.
■ L8104D has one sensing bulb and manual reset
pushbutton.
68-0063-3
■ Temperature range is factory-set to meet application
requirements. Maximum setting temperature is 200°F
(93°C).
■ ECO limit setting is factory-set to meet application
requirements.
■ For L8104A,B, standing pilot must be manually re-
lit or ignition module must be reset when ECO shuts
off gas control.
■ For L8104C,D, ignition module must be reset using
pushbutton switch mounted on electronic control
module when ECO shuts off gas control.
■ Control circuit is accurate within ±3.5°F (1.9°C) at
maximum setpoint (200°F [93°C]; setpoint controls
are accurate within +7°F [+3.8°C], -0°F [-0°C]).
CONTENTS
Specifications ................................................. 2
Ordering Information ..................................... 2
Installation ..................................................... 5
Setting and Checkout.................................... 10
Operation ..................................................... 11
Troubleshooting ........................................... 12
Material Safety Data Sheets ......................... 15