TESTING SUBMERSIBLE PUMP
Many times when your pump fails, the control box is the culprit. Testing the control box for 1/2 hp up through 1 hp is fairly simple. First thing to determine is whether you have a CRC or QD control box. The CRC has a start and a run capacitor, and the QD control box has just a single capacitor. Most 1/2 hp through 1 hp control boxes will be the QD type, with the blue relay.
We will concentrate on the QD style control box, which is most popular. Be sure to turn off the power to the control box before doing any testing.
The Triac test is done with your meter set to R x 1000. Connect between CAP and B terminals on the relay. The correct test reading should be infinity.
Test the coil by setting your meter to R x 1. Connect to L1 and B on the relay. The correct reading should be zero ohms.
Testing of the Capacitor is done by setting your meter to R x 1000 and after disconnecting leads from one side of the capacitor, connect meter leads to the capacitor terminals, and the pointer of your meter should swing toward zero, then drift back toward infinity.
If you are having pump problems, and the testing is not conclusive, we recommend that you replace the control box. Control Boxes are inexpensive, and are a better way to fix the problem, than changing out parts. A new part, in with old parts, can make the control box work, but still have weak parts, which can lead to later failures.
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