Tuesday, June 18, 2013

Irrigation Pump Failure

Every October I pull in our irrigation pump due to pipes freezing and cracking and also high creek water flooding the pump area occasionally. Then in about May I reconnect the pump. This year after reinstalling the pump which takes about an hour the pump motor did not start or even hum.

After inspecting the pump pressure switch I found it in terrible condition. Lots of corrosion likely due to entry of rain water all last year. I was able to clean it up much to my amazement and it is likely as good as new. Two lug screws were so damaged I replaced them with some ground screws which I do not use down there by the creek. (I don’t want a better ground down there than at the house which may draw too much current for the #12 wiring.) After reassembling the pressure switch, the pump still did not power up or even hum.

I found a little one inch round device that sort of looked like a time delay for a start coil on the motor. This device was corroded and was a likely culprit. (The device is labeled Klixon CET54CY 12A with 3 connections.) I did measure the resistance of the two windings in the motor and they both had continuity. So I used the web mail at Center Electric and asked if they had a replacement. No answer for 4 days so I called them this morning. The guy did not even know they had web mail. Oh-well, he knew right off what the device was. It is an over current protection device. (12 Amps). It has a heating element that under an over current condition, heats up a disk which makes the disk convex rather than concave which opens up the power to the motor. Interestingly the Center Electric person says these devices take about 6 month to order and cost about $60. He recommended just joining all 3 wires together effectively bypassing the protection.

I tried joining the logical 2 wires together and no luck. When I joined all 3 wires together the motor ran fine.

This pump is an old dog with a separate jet plumed with it. (A. O. Smith Corporation motor SKGET54CY mod C48K2FB4. I use it to pump creek water to the lawn and for other non-domestic uses. I was able to get it all running today and watered the lawn.

Over Current Protector

Disk from Over Current Protector
Notice flame for testing.
I was curious how it worked.

This old pump with jet.

Over Current Protector installed.

Note - The AC start capacitor also was damaged and I was able to get a new one from and outfit called Jafco for $2. However a minimum order of $10 plus shipping. So I ended up with a few extra items ordered.