AO Smith 3/4 HP Full Rate Two Speed - B2973T Fault 12

Herkdriver

Member
Aug 21, 2014
17
Biloxi, MS
I recently installed the 3/4 HP Full Rate Two Speed Motor W/ Timer 115V - Round Flange - B2973T to replace a failed single speed motor. Here’s the retailer link: A.O. Smith 3/4 HP Full Rate Two Speed Motor W/ Timer 115V - Round Flange - B2973T - INYOPools.com

It works fine on low speed. On high speed, after 2 minutes of runtime, it throws a “fault 12 overload” code. After a few minutes of being shutdown with power removed, the code is cleared and the motor runs fine on low speed.

The retailer has no experience with this code. They sent a lower HP impeller, but to no avail. Fault 12, the same problem, still occurs after 2 minutes.

Does anyone have any knowledge of how to resolve this? Thanks, much appreciated!
 

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JamesW

TFP Expert
Mar 2, 2011
24,835
What impeller is currently on the pump?

Do you have a picture of the old motor?

What is the voltage as measured line to line?
 

Herkdriver

Member
Aug 21, 2014
17
Biloxi, MS
It is caused by motor overload:


When changing the motor did you make sure the seal was installed in the correct direction?

If unsure, post pictures of both sides.

thanks for the reply...I’m pretty sure I installed it correctly, as per the instructions. But I’ll pull the motor again and snap a picture. Standby...
 

Herkdriver

Member
Aug 21, 2014
17
Biloxi, MS
What impeller is currently on the pump?

Do you have a picture of the old motor?

What is the voltage as measured line to line?

The current impeller is the Hayward SPX2605C. The retailer suggested I try this one to cure the fault 12. Initially after upgrading to the new 2 speed pump, I was using the Hayward SP2607C.

A pic of the old motor is below. Voltage is 115V.
 

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JamesW

TFP Expert
Mar 2, 2011
24,835
The SP2607C impeller should have been fine.

The motor was made in 2016, which seems odd.

Check to see if the shaft spins easily.

If the shaft is not binding, check the voltage and current while the pump is on to see if they are correct.
 

Herkdriver

Member
Aug 21, 2014
17
Biloxi, MS
Okay I think I’ve wired it incorrectly. I have a blue, white and green wire coming from the timer. I’m thinking (after some research) that I should have another wire for the 115v two speed motor. Unfortunately the new motor did not come with wiring instruction, but it’s my bad for not digging deeper to get it right, or hire an electrician! Here are pictures of what I have:
 

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JamesW

TFP Expert
Mar 2, 2011
24,835
It looks like the L1 wire is making contact with the L2 screw causing a short.

There's probably a nick in the insulation.

You can see the black burn marks on the screw.

Otherwise, it looks correct.

In my opinion, the terminal arrangement is poorly designed and likely to cause this type of problem.
 
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Herkdriver

Member
Aug 21, 2014
17
Biloxi, MS
Okay, yeah I see what you’re saying. So only an L1 (blue wire) and L2 (white wire) plus the green ground wire? I’ll open it up and reroute that blue wire. Thank you!
 

Herkdriver

Member
Aug 21, 2014
17
Biloxi, MS
Blue wire rerouted, well clear of the white/L2 terminal. Motor works fine on low speed. Works on hi for 2 mins, then Fault 12. I’ll pull the impeller today and look at that seal, and report back w/ pics
 
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