Potable water pressure problem

[Aerobaticflyer]

My 390 DA now has very low pressure when connected to dock water. When on on board system with pump pressure is good but pump won't shut off. Maybe two separate issues? So far I have:

Checked screen on water connection from dock. It was clean.

Checked end filter screen on pump inlet side. It was clean.

Tried different hose and no change.

Any suggestions?

 

[endless seas]

We always had much lower pressure using dock side water hook up. Even had the regulator changed so we just use the pumps as they are much much better.

 

[my3sons]

We always had much lower pressure using dock side water hook up. Even had the regulator changed so we just use the pumps as they are much much better.

Yep, I did that on the 360, new regulator made no difference. On the current boat, we just live with it. We have good pressure at the dock hose, so it's not that.
The PO's of our boat used the pumps all the time because of it, and that was a different marina. I think the regulators just "regulate" too much.

 

[dwna1a]

Could be one issue.... You've got a leak somewhere in the system. Low pressure from the dockside, causing low water flow. Pump never shutting off, meaning it never gets to the shut off pressure setting. Just me, but sounds to me as a leak. Only three things drop pressure at the tip. Bad pump, low inlet pressure, or a leak in the hose. If you've check for blockage at the pump (inlet pressure), you may want to pull the inlet line at the pump and be sure the water flow is good. The next thing would be the pump, remove the outlet hose and cut the pump on, check the discharge. All that's left is the hose (system).

20 some years as a pump/operator at JCCFD

 

[Aerobaticflyer]

Could be one issue.... You've got a leak somewhere in the system. Low pressure from the dockside, causing low water flow. Pump never shutting off, meaning it never gets to the shut off pressure setting. Just me, but sounds to me as a leak. Only three things drop pressure at the tip. Bad pump, low inlet pressure, or a leak in the hose. If you've check for blockage at the pump (inlet pressure), you may want to pull the inlet line at the pump and be sure the water flow is good. The next thing would be the pump, remove the outlet hose and cut the pump on, check the discharge. All that's left is the hose (system).

20 some years as a pump/operator at JCCFD

I think if I had a leak it would be evident somewhere. I'm thinking pressure regulator, assuming it has one. Probably buried by the tank forward of the bulkhead.

 

[electricaldoctor]

If the pump won't shut off, check the pressure switch on the water pump .

 

[cod]

May be a silly question but is there water in the tank? Being connected to city water does not fill the tank or have anything to do with the pump. City water pressure I found is usually lower than what you get with the on board pump.

 

[endless seas]

Good question I was afraid to ask.

 

[Skuza]

How about a kinked line? I found one inside the transom after a leak developed. Turns out the line kinked and developed a hairline crack which was the cause of the leak.
The regulator fixed our low pressure dockside problem.

 

[Aerobaticflyer]

May be a silly question but is there water in the tank? Being connected to city water does not fill the tank or have anything to do with the pump. City water pressure I found is usually lower than what you get with the on board pump.

No I get all that - two separate water sources. Yes there is water in the tank.

 

[Alex F]

My 390 DA now has very low pressure when connected to dock water. When on on board system with pump pressure is good but pump won't shut off. Maybe two separate issues? So far I have:

Checked screen on water connection from dock. It was clean.

Checked end filter screen on pump inlet side. It was clean.

Tried different hose and no change.

Any suggestions?

These are two separate issues, so don't get mixed up.

After couple of season with my 320DA I lost water pressure from the dock. New regulator ($45 part from MM) resolved it.

Water pump won't shut off could be few things. The leaks are not always that obvious, so don't rule it out. If you're 100% sure that there are zero leaks check HWH pressure relieve valve.

 

[mwph]

Just a reminder since I didn't see mention of it...

1. A "leak" doesn't always mean water. A loose fitting especially on the inlet side of the pump can allow air into the system which can prevent the pump from fully pressurizing the system.

2. The pressure adjustment on the pump itself can obviously be "adjusted". I did read where some of them can actually be replaced if you can find the right one. But other than that taking apart the pump to service it is not really an option. It looked to me like you could split atoms inside what I thought to be a very complex design. (I disassembled one just to learn).