Checking the Coil, the DIN Connector, and the Power to the DIN Connector

Inspecting the Danfoss EDV Valve and the Danfoss 3/2 Valves with EDV for signs of malfunction, should first include an inspection to make sure the DIN Connector and Power Cord are functioning correctly.  The following is a description of checking the DIN Connector with an image below showing four DIN Connectors connected to Zone Danfoss 3/2 Valves with EDV (drain) function built in.

Checking the coil, theDIN connector, and the power to theDIN connector is suggested as follows:

Initially, if you place your fingers on the coil and turn the pump on, you should feel the internal piston ‘clicking’ into position which means the coil, theDIN, and the valve are probably working as needed.  You can also sometimes hear the clicking (if it is a relatively quiet pump).

If you cannot determine the valve function using this simple test, check the coil by simply looking at it to make sure there are no protrusions (caused by a short in the coil and a resulting ‘explosion’ that changes the outer profile of the coil body).  You will typically see a bulging side or an actual hole in the coil body.

If the coil looks bad, it will need to be replaced.  To determine the cause (which is not always determinable), remove the coil from the valve stem and inspect the valve stem to see if there is any discoloration or rust or the presence of water that would cause the coil to short.  If there is, the valve stem will need to be replaced.  We have seen some of these stems fail at the point of the weld around the circumference of the stem allowing water to leak out which then causes the coil to fail.

If the coil does not look bad, remove the small Phillips screw from the front face of theDIN connector (the connector is the component that is attached to the three prongs on the coil) and remove theDIN connector from the coil.  Check the prongs for discoloration (usually carbon buildup as a result of a short circuit).  If there is obvious damage, the dDIN will need to be replaced.  This failure can be caused by moisture but more likely caused by the connections in theDIN connector being crossed or two of the wires touching.

If none of this leads to an answer, I would next place theDIN back on the coil leaving enough room to get the prongs from a multi meter between theDIN and the coil so that you can touch each prong to one of the top two prongs check to make sure the coil is actually getting the power from the source.  If there is no power at these prongs, then the power source for the coil is not being energized.

This is a standard DIN connector used with the Humidity Control Pump Station System.  It is used to provide the power supply to the valve coil (the blue component on the Danfoss valve and the black component on the Granzow [solenoid] valve).