Honeywell L8104B - Manual (Page 12)

68-0063—3 12
L8104A,B,C,D
TROUBLESHOOTING
DISCONNECT SENSOR LEADS FROM ELECTRONIC
CONTROL MODULE AND MEASURE RESISTANCE OF
SENSOR(S) WITH OHMMETER.
IS RESISTANCE BETWEEN 700K AND 30K OHMS
(SEE TABLE 1)?
SENSOR(S) OK. DISCONNECT ECO LEADS AND
MEASURE RESISTANCE WITH OHMMETER. IS WATER
TEMPERATURE GREATER THAN 210˚F AND ECO
RESISTANCE LESS THAN 10 OHMS (SHORTED)?
IS THE POTENTIOMETER REMOTE?
DISCONNECT POTENTIOMETER LEADS FROM
ELECTRONIC CONTROL MODULE. MEASURE
RESISTANCE OF POTENTIOMETER WITH OHMMETER.
IS RESISTANCE GREATER THAN 1000 OHMS AT MINIMUM
TEMPERATURE SETTING (CHECKS FOR SHORT)?
POTENTIOMETER OK. REPLACE ELECTRONIC CONTROL
MODULE. RECONNECT ALL LEADS AND CHECK OUT
SYSTEM.
SENSOR(S) MAY BE SHORTED OR OPEN.
CHECK FOR LOOSE, BROKEN OR SHORTED WIRES.
REPLACE SENSING BULB(S) IF NECESSARY.
REPLACE SENSING BULB WITH ECO LIMIT AND
CHECK OUT BALANCE OF SYSTEM.
REPLACE ELECTRONIC CONTROL MODULE.
RECONNECT ALL LEADS AND CHECK OUT SYSTEM.
REPLACE POTENTIOMETER.
RECONNECT ALL LEADS AND CHECK OUT SYSTEM.
START
NO
YES
YES
NO
NO
NO
YES
M134B
YES
L8104A, B, C, D
Troubleshooting
If water temperature is too hot, proceed as follows: