Starite 400N Service heater light, AFS and no fan start (at all) new board, and senso

[ljackski]

I've read thru A LOT of threads on this topic and I'm hoping someone can help. and I'm hoping it's not a repost.

My issue started with the Thermistor problem where the unit would start running, but temp would very quickly rise past 105 (shut off) and continue on to 126.
I replaced the thermistor and a new pad (it was toast).
When I buttoned it back up and powered on, the service heater light came on immediately and fan did not start turning at all.
I looked on the board and the AFS led was lit.
I replaced the AFS and still the same status. If i jump the AFS wires, the heater light comes on, but no fan.
Prior to ordering a new board, I rapped on the fan motor and hosing. No luck.
I can manually spin the fan in the housing and it would turn freely with the tip of a screwdriver.
I unplugged the motor and jumped (120v) the to see if it would run. It would run at a very low speed.
So, I replaced the board and I am still at the same status. Service heater light, AFS and no fan start (at all).
Your help is greatly appreciated.
Thanks!

 

[Pool Clown]

With a normally functioning heater, the service heater light will come on momentarily till the blower begins to spin and move enough air to close the AFS.

Look close at the windings of the blower motor. They should be a shiny copper color. If you see a streak of black or even a dark blue, get real close and smell. If it smells burnt at all, the blower is done.

 

[ljackski]

I dont see any obvious discoloration on the copper, although it is a quite a bit dusty and no smell of ozone or electrical burn. Also, when I look now in the ICM, the LED is blinking once.
It just seems odd that it quit after replacing the thermistor.

 

[Pool Clown]

One blink indicates air flow fault. We already know that!
You said you replaced the control board, so i'll skip that part.
Assuming the AFS is good, disconnect the IND wire from the ICM, and check the wire for 24VAC, this powers the ICM.
If you get power there replace wire and....
While the heater is in a call for heat state, check the F2 terminal on the fenwall. You should get 120 VAC. If no voltage, replace ICM (fenwall). If you get voltage, replace the wire, and inspect wire(s) to blower. If wires OK, replace blower.



Diagnostic flow courtesy Pentair 13-14 TTM