Sunday, September 29, 2013

PUMP IT UP: Repairing a FloJet 4300 Series Washdown Pump. Part Two

After diagnosing the problem with BIANKA's FloJet washdown pump and losing and then finding the replacement pressure switch. I was finally able to start the repair. The first issue to surface was to find which replacement pressure switch kit to use as there are several available. I contacted FloJet customer service who requested the model number and serial number for my pump. It turns out I need the  Flojet 02090118 40 PSI Pump Switch Kit for my model 4305-143 FloJet pump. Included with the replacement pump kit is a list of FloJet models and there replacement switch part numbers:

My FloJet pump has been on the boat since I bought it in 1995 and probably longer perhaps as far back as 1986. In the time since FloJet has changed the design of the pressure switch and as a result there are less parts involved and some that are eliminated altogether. The instructions show which parts need to be removed and how to install the new ones:

Here is what my pumped looked like after I removed the old pressure switch and the parts I would be discarding:

Here is what comes with the new replacement pressure switch kit:

Much less parts to deal with than the old pump. There are three pump diaphragms that come with the new kit:

As explained in the instructions which one you use depends on the liquid that will be flowing through the pump. They are labeled V, B and E. Which stand for Viton, Buna and EPDM. For potable water and seawater the instructions say to use the diaphragm labeled E for EPDM. There are some subtle changes in the replacement diaphragms too.  Here is a new Buna diaphragm on the right compared to the old diaphragm removed from the pump on the left. Notice that the lip on the new diaphragm is a little different. So it is best to discard the old one and not keep it around as a spare:

Here is the new EPDM diaphragm installed on the pump:

The new  Flojet 02090118 40 PSI Pump Switch  comes with black wires attached:

I swapped them with the red wires (also included in the replacement kit) since the switch will be switch the + 12 volt voltage:

Once the EPDM diaphragm was installed on the pump body one carefully aligns the switch module so that the diaphragm is not pinched  and screw holes are aligned and screws one screw snug and then the other to about 9-10 inch pounds. I just snugged them by feel and had no leaks.

In addition to replacing the switch I also took the opportunity to add Anderson Powerpole connector to the pump and switch wires. This will make it easier to troubleshoot the switch or even by pass the switch completely:

With the new pressure switch installed and Powerpole connectors installed the pump is ready to be reinstalled:

I was curious about the defective pressure switch. I had to cut the plastic off of the switch area and took a look at it after it was removed and it was a little more complicated than I imagined:

There are springs and two contacts that connect to each of the terminals. The failure of the switch seemed to be a combination of corrosion and bad contacts. Still it lasted eighteen plus years without a problem. Hopefully the replacement will last just as long.

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