A better way to wire a Washdown pump?

HenryD · Jan 2, 2015

happy new year,

I have a Jabsco Par-Max 7.0 washdown pump that is wired to the 12v bus with a 40amp breaker. To turn on/off the pump, I first need to go into the engine room and power on that breaker.
The pump also has an on-demand pressure switch, which has a 12v wire to the helm station switch.
My normal procedure is to open the thru-hull and turn on the breaker before leaving the dock, and then use the helm switch to activate the pump as needed - washing the bow or cleaning the anchor chain, etc.
I have had two of the pressure switches fail and recently it failed - ON, meaning the pump continue to run for several hours after the washdown had been used. I am trying to figure a way to wire the pump perhaps with a relay or a solenoid so the 36amp draw is from the battery bus, and the lighter wire to the helm controls the on/off.
Can I jumper the pressure switch so it always is on, and then use a relay or solenoid to send power to the pump as needed?
Suggestions?

O C Diver · Jan 2, 2015

Maybe I'm misunderstanding you, you already have a switch at the helm that controls the pump? If so, turn the pump on to use it, and off when done.

Ted

HenryD · Jan 2, 2015

Ted,
The switch at the helm completes the circuit for the on demand pressure switch. The pressure switch has been replaced twice. I would like to take it out of the system and have the helm switch control the power to the pump.
Thanks - hjd

koliver · Jan 2, 2015

Must be bad equipment.
20 years ago, I added a washdown pump. I had a spare thruhull, to which I plumbed the pump. I piped the water to both ends of the boat, valves and garden tap fittings. Now, when I want salt water at the bow or at the stern, I switch on the pump, open one of the valves, and I have water. At the bow I have both a hose bib and a pipe directed at the anchor chain so when a muddy chain is being hoisted aboard, it can be sprayed, or I can use the hose. Good equipment originally, and no hiccups whatsoever in 20 years.

N4712 · Jan 2, 2015

What about one of these?
http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=1F6P447XQEPVTT2XGMY5

and Yes I Would just jump the pressure switch.

ksanders · Jan 2, 2015

HenryD said:
happy new year,

I have a Jabsco Par-Max 7.0 washdown pump that is wired to the 12v bus with a 40amp breaker. To turn on/off the pump, I first need to go into the engine room and power on that breaker.
The pump also has an on-demand pressure switch, which has a 12v wire to the helm station switch.
My normal procedure is to open the thru-hull and turn on the breaker before leaving the dock, and then use the helm switch to activate the pump as needed - washing the bow or cleaning the anchor chain, etc.
I have had two of the pressure switches fail and recently it failed - ON, meaning the pump continue to run for several hours after the washdown had been used. I am trying to figure a way to wire the pump perhaps with a relay or a solenoid so the 36amp draw is from the battery bus, and the lighter wire to the helm controls the on/off.
Can I jumper the pressure switch so it always is on, and then use a relay or solenoid to send power to the pump as needed?
Suggestions?

Now I get it!

Your pump draws 36 amps and you want to control it from your helm station.

Use a relay

HopCar · Jan 2, 2015

I think there is a problem with your installation. The pressure switch shouldn't fail that often. A restricted output will cause quick cycling of the switch and destroy it very quickly. The Par Max 7 puts out a lot of pressure and volume. If the plumbing, hose or nozzle are too small it can cause the switch to fail. You could try a smaller pump or install an accumulator tank.

Another thing that can cause problems would be undersized wiring. It sounds like you've got a pretty long wiring run. That pump draws a lot of amps and will need a pretty big wire.

Instead of trying to work around the problem, I think you should fix the problem.

O C Diver · Jan 2, 2015

HenryD said:
Ted,
The switch at the helm completes the circuit for the on demand pressure switch. The pressure switch has been replaced twice. I would like to take it out of the system and have the helm switch control the power to the pump.
Thanks - hjd

Need to have a pressure or don't close off the oulet of the pump. You could use the helm switch to activate a relay to activate the pump.

In general, pressure switches are very reliable. Think about the pressure switch on your domestic water system. What amazes me is the amp draw of that pump. If I had to guess, the huge amp draw of that pump was welding the contacts on those pressure switches. Might want to consider a smaller pump. The Jabsco par 5 (5 gallons per minute @ 50 psi) only draws only 12 amps, not the 28 amps your 7 GPM pump draws at @ 80 psi. Just a thought.

Ted

C lectric · Jan 2, 2015

For a 36A load your panel switch will be the next thing to go.
Do not get rid of the pressure switch. Those switches are simply not rated for the current level or for direct motor control of that size.. They will give YEARS of reliable service but the whole circuit needs to be done properly. It's not as it is now.

You need to add a H.D. relay such as from Cole Hersey.
http://www.colehersee.com/home/grid/cat/168/

Then the pressure switch should control the HD relay using only an amp or two.
The panel switch is in series with the pressure switch so the pressure switch can be deenergized killing the circuit and thus the pump. You still keep the 40A breaker in line with the power to the relay

I made up a quick schematic but I cannot post it. Lousy internet where I am.

Send me an e-amil through ths site and I should be able to send you the schematic that way.

C lectric · Jan 2, 2015

OK,
I think I got it posted. Take a look at the link.
There are a couple additions that will help the circuit last even better BUT I don't have the p/n available now.

Darn near forgot to put in the pressure switch. Please excuse the squiggly crossed out line.

Too much rush. The dashed rectangular line is the relay case..

Yup, too much rush. Ignore the 'alternate ctrl sw". There is a better way but I'm done fo rthe night. This will show the guts of a circuit that will last.

FF · Jan 3, 2015

A second option might be to sell the 36A DC pump , and replace it with a common house water system pump.

These are cheap enough and will put out 60 PSI thru a 1 1/2 pipe , enough to get most of the mud off anchor chain.
All plastic so no sea water hassles.

The starting loads (pumps are centrifugal) are not bad for a small inverter , which makes wiring far easier.

The AC power does not weld the points as DC does to the pressure switches, which are cheap at any box store.

In addition with a couple of valves a better sized powerful bilge pump could be had.

HiDHo · Jan 9, 2015

I put a tee in the discharge hose from the ShurFlo potable water pump. Ran a length hose up to the storage lockers either side of the pilothouse installed a hose valve and made up a hose with pistol grip sprayer, it works great. Best thing is no funky water going down into the chain locker. The Manatee's are plumbed with a potable hose fitting aft for washing down the after deck area or handy for swim shower, so I figured why not put one up forward. The ShurFlo advertises a 100 ft head which is hard to believe, it has no problem pumping the water up about 10 ft.

A better way to wire a Washdown pump?

HenryD

Senior Member

O C Diver

Guru

HenryD

Senior Member

koliver

Guru

N4712

Guru

ksanders

Moderator Emeritus

HopCar

Guru

O C Diver

Guru

C lectric

Guru

C lectric

Guru

Attachments

FF

Guru

HiDHo

Guru

Similar threads

Latest posts