To Next Page

To Previous Page

ADVANCEDBACK

0 days 0 hr 0 min ago

Error Code: 175-0

Flow Not Detected

Flow was not detected when in

heating state.

Press the Advanced button for

more information

Figure 16. Flow Fault Detected Warning Message

Figure 17. Pump Terminal Wiring

Whenever the water ow is not detected during the heating cycle, the water heater is turned off with “Flow Not Detected” error

displayed, take the following steps to trouble-shoot & x the problem:

1. Turn the water heater on and wait for the ame icon displayed on UIM.

2. If 120VAC voltage is NOT detected at the pump’s wiring terminal L & N when the ame icon is displayed on the UIM, check the wiring

connections between the CCB & the pump and the pump relay mounted on the CCB. See Figure 17.

3. If the 120VAC volt is detected at the pump wiring terminals but the pump is not running ( a faint pump vibration can be sensed by

touching the pump motor when it’s running), the pump needs to be replaced.

4. If the pump is conrmed to be running during the ame icon displayed on UIM, check the following items:

• Conrm the check valve inside the pump’s outlet is installed correctly if it’s a new heater /installation;

• Conrm the ow switch is installed vertically with ow arrow pointed upward;

• Conrm the ow switch’s vane can swing freely;

• Check the blockage inside the pump and the secondary HEX, a minimal ow rate required to activate the switch is 5GPM per

design.

13. FLOW SWITCH STUCK CLOSED

A water ow switch is installed at the outlet of the secondary HEX to conrm water owing through the secondary HEX whenever the

heater is on. The ow switch is set at “Normally Open” during the standby (no water ow) and closes when water ows. If the ow

switch is closed during the standby mode, the “ow switch stuck closed” warning will display on UIM, but the heater will keep operating

normally. Take the following steps to remove the warning sign.

ADVANCEDBACKACCEPT

0 days 0 hrs 0 mins ago

Error Code: D6 -8

Flow Switch Stuck Closed

Flow switch should be open

when heater is in standby state.

1. Conrm the pump is not running during the standby cycle. If the pump runs during the standby mode, it indicates that the pump’s relay

is stuck closed, a new CCB will be required;

2. Conrm the ow switch is preset at “Normally Open” by observing the “NO” letter visible on the ow sensor (factory default);

A.O. Smith Cyclone XL 100 Series User Manual

Questions and Answers: