Thread Number: 56570
1976 Superba constantly running timer issue |
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Post# 788986 , Reply# 4   10/14/2014 at 12:14 (3,474 days old) by DADoES (TX, U.S. of A.)   |   | |
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Post# 789031 , Reply# 6   10/14/2014 at 18:42 (3,474 days old) by DADoES (TX, U.S. of A.)   |   | |
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The arm support shaft should *not* turn. Don't wrench a wrench or pliers on it lest it break loose. The arm rotates on the shaft via the water spraying out of it, same as does a rotary lawn sprinkler.
No water, first step is check the fill valve where the incoming water line is connected. To be 100% sure the supply line is OK, disconnect it from the valve and run it into a bucket. Then test the valve solenoids with a meter. |
Post# 789078 , Reply# 7   10/15/2014 at 05:55 (3,473 days old) by combo52 (50 Year Repair Tech Beltsville,Md)   |   | |
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Hi Steve, I think your thoughts on the orignal problem are right on the money.
The non filling issue could be a clogged tube going to the over-fill switch, a bad over-fill switch and of coerce a bad fill valve. At this point you have to test to see if a 120 volts is getting to the fill valve, if so replace the fill valve. On a DW of this age it is a good idea to replace this valve even if it seems to work. John L. |
Post# 795012 , Reply# 14   11/19/2014 at 21:53 (3,438 days old) by barcoboy (Canada)   |   | |
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I believe your diagnosis is correct in either the pressure switch or timer being at fault, with my hunch being the pressure switch. It would depend on how the 17 normally operates that would determine which is to blame. If the 17 works the same way as an 18 does, with the obvious difference in that the 18 uses a float switch instead of a pressure switch, the timer normally controls the duration of the fill, and the switch is only to shut off the fill valve in case the timer for whatever reason keeps the water on too long and the water level gets too high. The other way that the 17 might work is that the timer sends power to the fill valve for multiple increments and the pressure switch is used to determine the level to turn off the valve. In either case, the pressure switch should be wired in line between the timer and fill valve. Since your fill valve is new, I doubt that it is to blame, and if the timer was faulty, the pressure switch would also have to be faulty for the timer to continue to be able to send power to the fill valve. The sure way to find the culprit would be to test the pressure switch with a multimeter, either by doing a continuity check when the dishwasher is both empty and full of water (switch should be closed when empty, and open when full), or by taking voltage readings at the switch and make sure the voltage drops down to 0 when the dishwasher is full of water. Of course if you aren't comfortable doing this, don't... find someone to help you.
Of course not ever having seen a 17 or a wiring diagram for one, the fill system could work completely different than an 18... someone will soon confirm or dis-confirm what I have written, as well as tell us which way the fill works. |
Post# 795085 , Reply# 15   11/20/2014 at 08:49 (3,437 days old) by Creed ()   |   | |
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Thanks barcoboy! I'll give it a try with the multimeter to see what I get. |
Post# 795087 , Reply# 16   11/20/2014 at 08:56 (3,437 days old) by DADoES (TX, U.S. of A.)   |   | |
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Could be that the flow rate of the replacement valve is a bit high. Fill periods are timed, with a flow-washer in the inlet valve to moderate the GPM flow over a range of household supply pressures. The pressure switch is only for overfill protection. A small amount of leaking can occur if the tub level reaches the pressure switch trigger point ... but typically that doesn't happen (per my experience with a KDI-17a) unless the machine is paused and restarted with a maximum fill, if the spray arm sloshes some water out of the door vent. |