Water Pump Pressure Switch

[a64pilot]

This is the switch that my Jabsco pump uses. The factory switch has a wire soldered on one terminal and a spade on the other, a spade works fine for both and makes changing the switch easier.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[Kalimniosjohn]

Originally Posted by GordMay

Jabsco Par-Max 3 Water Pressure System Pump, 12Volt, 3.5 GPM, 40 PSI Switch
Item #1 - Pressure Switch #18916-1040
$29.87 USD @ Fisheries Supply

Wow I may have to switch from the v-flow pump to a par max pump and add an accumulator tank. I’ve read many threads on these things and never seen this before. Thanks!

[Kalimniosjohn]

Originally Posted by a64pilot

This is the switch that my Jabsco pump uses. The factory switch has a wire soldered on one terminal and a spade on the other, a spade works fine for both and makes changing the switch easier.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Hmm also good to know. I took my pump out and fiddled with it and it seems to be working fine now but still runs slowly after I open an outlet occasionally. Next time it starts acting up again I’ll take it apart and see if mine has something similar.

[Bruce K]

I changed both my pressure pumps to Marco UP3/E, which are variable speed gear pumps, they seem to be very reliable, and so quiet that I cam hardly hear them.

[CatNewBee]

Same here, pump does not turn off, the over pressure protection valve at the boiler releases the fresh water to the bilge and the bilge pump takes it over board...

Easy fix It was a loosen adjustment screw in the pressure switch that was protected by a red paint dot from loosening Now a pink dot of nail polish paint secures it for the next years... .

[Elie]

Long time ago I had this problem. Replaced 3 pumps only to discover later on that a small air leak somewhere into the tubing was the cause of the problem when the tank was alf empty. I fixed that leak, and the problem was solved. These diaphragm pumps are tough, but they don't like pumping air...

[deluxe68]

This subject came up a while back. If I remember right the culprit was the pressure sensor freaking out under low voltage. Some are very sensitive to the battery voltage. I cannot remember if the previous discussion was geared to a specific brand.

[eriknoed]

Originally Posted by CatNewBee

Same here, pump does not turn off, the over pressure protection valve at the boiler releases the fresh water to the bilge and the bilge pump takes it over board...

Easy fix It was a loosen adjustment screw in the pressure switch that was protected by a red paint dot from loosening Now a pink dot of nail polish paint secures it for the next years... .

Do I read, that loosening the adjustment screw increases the pressure?
Fair winds.
Erik

[jamhass]

Couple of thoughts:

1. Yes, inexpensive 120v pump pressure switches work just fine on 12 volt pumps.
2. If you are having arcing issues affecting contact pitting/corrosion/lifetime, simply add an automotive distributors capacitor across the points.
3. If your Jabsco (or other pumps) with built-in electronic speed controls fail, it is usually the internal circuit board that goes, not the sensor itself. Not too difficult to bypass the board and adapt to #1 above (or in a pinch bypass the internals and use an external manual switch or the circuit breaker until a proper fix can be implimented.

[raingolfer]

Originally Posted by Bill O

Most of the diaphragm pumps to be used for fresh water systems should already have a pressure switch built into the pump, so you should not need a separate pressure. Yes, you will need an accumulator tank. Depending on how well you want to dampen the pump pulses, look for one with a rubber diaphragm in it w/a Schrader valve to add air pressure behind it.

We used diaphragm pumps a long time ago, while very dependable tended to be much louder, pulsed more (even w/an accumulator) than the Flojet type pumps we currently use. Our pump has been in the system for years and been very dependable. Some of the symptoms of the continuous run sounds like a leak or air in the system, not allowing it do come to full pressure. Other causes could be debris getting past the filter (I assume you have a filter) getting into the pump head diaphragm or a clogged filter decreasing flow to the pump. We use a very large filter (similar to RO pre-filters) which have a very large capacity. A long shot could be your tank pick ups are clogged and starving the pump for water. If you have aluminum tanks and any chlorinated water been put in them, they could have a large amount of aluminum oxide chunks blocking the pick up.


Bill O.

What's involved in cleaning the pump head diaphragm? I replaced our pump recently, and it was quiet and working great. Recently it has started being noisy and running longer (like the previous pump), so I'm suspecting a clog. Especially, since we don't have a filter inline before the pump (yet, installing that now).

[Lepke]

Yes, a Square D switch will work. No, it's not rated for 12v, but will last for years. If your pump has the pressure switch in front of the pump housing, it uses a micro switch that looks similar to the one shown. The switch isn't rated for 12v, but it's cheap for the mfg to use. The contacts stick after awhile. It's easy to change. A couple screws.
About $5-6 on ebay or Amazon. Sometimes you can find a higher rated switch. Less if you buy in bulk.

[Bowdrie]

The Square D switches are a no brainer, and they are available most anywhere at "non marine store" prices.
The big gain is that both the cut-in/cut-out are adjustable, so that you can fine tune your system.
No matter the size of the lines or the capacity of the accumulator tank you can get settings that provide a reasonably steady flow.