Test 11: Water Heater Shutting Off Below Setting - A.O. Smith SERIES 120 Service Handbook

TEST 11: WATER HEATER SHUTTING OFF BELOW SETTING

Conditions:
• Main burner ignited
• Stored water is below temperature setting more than 5° F (Tank Average).
• Power off
• Plug disconnected from heater control board receptacle E3 and E4
TEST 11
IF.........
Continuity check pin to pin of lower temperature
probe shows 1 or 0 (E4)
Continuity check red wire pin to red wire pin on
upper temperature sensor shows 1 or 0 (E3)
All above checks are okay
Servicing should only be performed by a Qualifi ed Service Agent
TROUBLESHOOTING
E3
E4
Figure 30
WATER HEATER SHUTTING OFF BELOW SETTING
(Water Temperature Circuit Check - Continuity)
then............
See Test 4.
• check wiring and plug connections to heater control board receptacle E4.
• replace lower temperature probe.
See Test 4.
• check wiring and plug connections to heater control board receptacle.
• replace upper temperature probe.
• Check wiring and plug connections to heater control board receptacle.
• Replace upper temperature probe.
37