Hot water pressure too low

[watercolours]

Ahoy fellow sailors,

I'm having a problem with hot water pressure.

Cold water pressure works great through all faucets.
Hot water does not. It's only a small, weak stream, and when you turn on the hot water, the Jabsco pump goes on only about 10% in power and sound. (The pump works loud and strong when pumping cold water).
Through research, I'm told that water pressure on the pump effects how strong the pump works.
I bled the lines, but still the same issue.

There must be a blockage in the Force10 water heater, or perhaps a line to or from the heater.

Does anyone have any experience with this, or would know what to do?

Thank you in advance.
John

 

[gfrazzle]

Water flow

I would disconnect the inlet hose and test the flow first. If good, then test the outlet pressure to see if the blockage is in the heater. IF not, it is likely in the distribution manifold under the galley sink.

 

[watercolours]

Re: Water flow

Thank you.
I'll do that tonight when I get back on board.
Will update tomorrow.

thanks again

 

[kloudie1]

First, clean the little aerators that unscrew from the end of the faucet where the water comes out.. then go to the manifolds and tank.

 

[watercolours]

thanks.
I checked aerators, but not all of them.
I'll check all of them tonight, and then disconnect hoses to manifold and tank if necessary.

Right now, after bleeding the faucets while the pump was off and the water heater tank was cool, the same problem exists, only with the hot water pressure.

Hopefully the above with fix this. I'll get back soon.

Thanks again
John

 

[kloudie1]

John, I had similar problems with gally sink faucet and found lots of calcium-looking scale in the hot side of the faucet pipes.. that stuff clogged the diverter valve for the hand squirter and plugged the aerator.. Head sink did not have a problem but the shower did.. all on hot side.. I don't think you'll have any problem finding and cleaning it.. Good Luck..

 

[Velero49]

Do you have a hot/cold mixer valve in your hw heater? On my 49 there is a hot/cold mixer valve at the hotwater side of the hw heater that regulates the water to prevent scalding. Maybe you have a bad mixer valve.

 

[watercolours]

This is great information. thank you!
I'll check this.

I pulled the 'water out' line at the water heater, but it was clean. It's red plastic. There's a bronze elbow at this joint that attaches the plastic water line to the heater.
Do you know if you're allowed to unscrew this fitting to inspect, or should it be permanent?

 

[watercolours]

Do you have a hot/cold mixer valve in your hw heater? On my 49 there is a hot/cold mixer valve at the hotwater side of the hw heater that regulates the water to prevent scalding. Maybe you have a bad mixer valve.

Good question! I don't know.
There is a valve with a round handle on top that you're supposed to turn to adjust hot or cold. It shows clockwise for hotter, counter clockwise for colder.

I'll look into inspecting this.

Thanks for your help. I'll get back.

John

 

[watercolours]

Thank you! I fixed it, and it works perfectly now!!!

I opened the water mix valve from 'Hot Water Out'.
There was a small screen, which had minerals from the tank blocking it.
I cleaned the screen, screwed back the valve, and turned on the hot water.
It's working 100% perfectly now!

I wish to really thank you for spending time to answer my questions.
You all helped so much. As a note, the manufacturer of the heater didn't know what to do,... but you did, and helped me a lot.

Thanks again to all.
John

 

[Velero49]

Hi John,

I looks like I have the same problem now.... Until now I suspected calcium deposits inside the valve (maybe what you are refering to as mineral deposits). Are they any other parts inside the mixing valve other than the screen?

 

[Nodak7]

On mine I found a screen in the coupling just before the mixing valve. Did not expect that and I would never had looked for a screen in that line but I disconnected it to install a HWH by-pass for winterization. There it was and I make sure I check it for blockage from now on.

 

[Rick486]

On mine I found a screen in the coupling just before the mixing valve. Did not expect that and I would never had looked for a screen in that line but I disconnected it to install a HWH by-pass for winterization. There it was and I make sure I check it for blockage from now on.

Nodek:

Nodek: By "mixing valve" do you mean the Temperature Control Valve which protects the heater from over temp/pressure when heated by the main engine coolant? I imagine I have the same setup as yours on my 44 DS and I don't see a mixing valve to mix hot water and cold water????