Kenmore UltraSoft 400 not cycling through valve positions


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Old 08-11-08, 12:11 PM
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Kenmore UltraSoft 400 not cycling through valve positions

I have a Kenmore UltraSoft 400 water softener. It is displaying an "Err3" on the PWA. When I try to manually advance through the cycles (by pressing the ON/OFF-HOLD button), it only displays Serv on the PWA screen. The cam continues to spin through all positions a number of times until it finally stops but only "Serv" is ever dispalyed. The final position of the valve when the cam stops seems to be random. I am not sure how it knows what valve position it is in since I don't see any kind of cam gear position indicator, just an on/off microswitch triggered by the cam. The only input to the PWA is power, turbine sensor, the cam position switch and power for the motor. My guess is it uses a combination of the the switch and turbine speed (possibly something else) or it just relys on the position switch and uses an internal step counter and everthing must be in the correct phase.

Anyway, my concern is that I can't step through the differnet valve positions manualy to do any diagnostics. I press the ON/OFF-HOLD button and the valve/cam just keeps spinning (as described above). My guess is that either the PWA is faulty (which would explain the lack of cycling through the on-screen valve position indicators) or there is a rotor/seal issue. Since I can't figure out how the physical valve position is communicated to the PWA I am not sure how the error is being figured by the PWA (unless the actual flow rate is computed in determining the valve position).

Any help would be greatly appreciated.
Thanks!!
 
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Old 08-11-08, 03:22 PM
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Most probably the error code indicates either the motor is defective or other wiring issues. Is your unit more than 4-5 years old? The plastic gears on these motor get damaged due to high torque of cam and it can skip various cycles.

One way to check if your valve is operating properly is to remove the motor from the cam and rotate it with hand. You should be able to rotate it with moderate hand pressure to cycle it through the fill/brine/rinse/backwash/service cycles. If the valve is hard to rotate, then, you may require replacement of the valve, seals and possibly new motor.

The sticky above this forum list mortonsalt site that has excellent interactive graphics and shows the various parts of the valve, seal, venturi and float. There are plenty of discussions in the past in these forum on how to replace seals and rotor in Kenmore units.
 
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Old 08-11-08, 04:37 PM
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The motor appears to be turning the cam without issue but it is not running through the cycles accoring to the PWA. Only "serv" is appearing on the PWA. If I knew how the PWA determines what cycle it is on, it would be a big help in diagnosing the issue. I will pop off the motor and turn the unit by hand and see what happens. Thank you for your help.
 
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Old 08-11-08, 09:15 PM
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Update - I was able to manually spin the cam by hand without too much effort. Even though the cam/valve spins through the cycles, the cycle position (fill/brine/rinse/bw/service) still does not show up on the PWA (it always displays service).
Any ideas what the issue might be?

I am still thinking the PWA itself or the valve rotor and valve seal.

Thanks!!
 
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Old 08-12-08, 09:09 AM
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If you look at the cam, you will see some notches on the OD. The arm from the microswitch rides on them and opens and closes based on the position of the notch and this tells the control unit to stop or continue to next cycle.

See if the arm from microswitch is properly making the contact with the cam through the cycles. Also check the output of microswitch with a volt meter to make sure it opens and closes as it supposed to at various positions on the cam.
 
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Old 08-12-08, 03:32 PM
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Yes, the cam opens and closes the microswitch just fine. When the switch closes, the valve closed symbol displays on the PWA, when it opens, the valve opened symbol displays on the PWA. I also opened and closed the switch with a small screwdriver, and the same result showed up on the PWA. I would think there would have to be some other input for the PWA to determine the valve cycle as the microswitch just tells the PWA that it is on or off. I guess the PWA could step through an internal counter everytime the switch closes and determine what valve cycle it is on. I would think that would leave lots of potential for it to get out of phase, but I guess it's possible. At any rate, the PWA still doesn't display any valve cycle on the PWA except for "serv". Another interesting thing, you mentioned there was a bar on the microswitch (the manual says the same thing as well), however, there is no bar on the microswitch, the cam hits the little button on the microswitch directly. This seems a little odd, but I guess it works all the same. Again, thanks for all your help.
 
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Old 08-14-08, 04:39 PM
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I re-read through one of the sites linked from the stiky. It "kind of" indicated that it used the microswitch and an internal counter in the PWA to determine the valve position. My guess is that it measures the time between each detent on the cam to determine position. One full revolution would be enough to determine its position if it did get out of phase. It could potentially be sophisticated enough to measure the delta between clicks, normalize those times and then determine position (by relative time differences) at any rotational speed. I doubt that it is that sophisticated. More likely what really happens is if the time doesn't match the pre-determined value (plus or minus some tolerance), then it throws an error code. This is just a guess on my part, but it seems to make the most sense. I took the motor off and turned it by hand. It does not seem to take a lot of torque to get it to go (I can turn it with three fingers grasping pretty firmly). Gusman1, can you by any chance tell me about how long the cam should take to make an entire revolution (while being turned with the motor)? That would help me to determine if it is spinning at the correct speed. At this point, I will probably just start repacing parts until it either works or I have to call someone who knows what they are doing. Third option would be to buy a new unit (this one is 7 years old).

I will probably start with a new motor/gearbox and seal/o-ring kit as these are the two issues listed in the manual when an error code of 3 is displayed. The motor/gearbox is about $45 and the seal/o-ring kit is about $47. Not too much of an investment to see if it will work again.

Any additional input would be appreciated.

Thanks!!
 
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Old 08-18-08, 03:34 PM
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The cycle times for each position should be listed in your manual. Typically it is 2-8 minutes for Fill, about 100 minutes for Brining, 4-5 minutes for Rinse and 2-3 minutes for Backwash.

If you push your 'Regenerate Now' button, the motor should move to first Fill position and then advance to next position when you push the button again. If yours goes through the complete cycle with one push, the microswitch is not giving the proper signal to the controller to stop. Therefore, I would first trouble shoot the switch, its wiring and its connection to the circuit board. Make sure it is connected to the right terminal.

If you are able to rotate the cam freely, your valve and seals should be OK. In the past, I had to get a new motor to eliminate the Err 3 code. So, if I were to going to change parts, it will be the motor and microswitch first. You can get motors and parts from eBay and other sources cheaper than Sears.
 
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Old 09-05-08, 01:11 AM
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Update

I ordered the parts and replaced the motor/gearbox and the seals/o-rings inside the valve body. It has been working just fine now.

Thanks for all your help!!
 
 

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