New plumbing install

[TheLake]

Hi all,

I am replumbing my CHB 42' trawler.

I am going to use a Grundfos Scala 2 AC pump and pex with a manifold.

I am attaching a diagram. I am considering not having a shore water line hook-up.

I am not sure about the water arrestor...if one should be installed and if it is installed before or after the manifold.

Other thoughts or concerns?

Thanks,
Chris

 

[tiltrider1]

Looks pretty basic. Nothing wrong with that.

I think skipping the shore water hook up is perfectly fine. Shore side hook ups were common back in the 80's when marine water pumps made poor pressure and volume. With modern water pumps I find using shore side hook ups to be greater risk than value.

 

[Turtle Blues]

One of the first things I replaced after purchase was a freeze damaged shore water inlet with prv. 3 years later have yet to use it. prefer to fill tanks.
pex is the way to go. pipe can freeze and thaw without damage, fittings, depends on material, still using brass with crimp rings but I'm old school.

 

[Nickwadsley]

You might want to put check valves just fwd of each tank

 

[Pete Meisinger]

I would skip the shore water hookup. You still see a few of them at marinas but they concern me because something could fail and you would eventually flood your boat.

Less serious is the fact that it is one more thing to unhook when leaving the dock. Shore power and dock lines are enough.

pete

 

[STB]

One detail caught my attention and I can't look away...

The Scala2 is a 208-230vac, 550w, 0.6hp pump rated up to 13gpm, and capable of producing up to 145psi (Configurable for constant pressure from 22psi to 80psi), no? Am I looking at the correct model?

Unless I'm looking at the wrong model, are you sure that's what you want? How do you plan to power it?

A 12vdc or 24vdc pump, matching your boat's electrical system, seems like it'd be a lot more convenient in a lot of cases. Do you have an application in mind that calls for the additional psi or flow rate of this pump vs more common marine pumps?

 

[O C Diver]

You definitely make nice diagrams that are easy to follow!

I would skip the shore connection also.

I used a much larger filter system, and did the whole water system. Less plumbing and all the water is good to drink.

As others have mentioned, marine DC pumps will go as high as 70 PSI. With a limited water supply, 5 to 7 GPM should be enough volume.

You didn't mention plumbing size, but suction lines from the tank to the pump may starve the pump. My 6 GPM pump requires 3/4". A larger pump may require more and the tank fittings may become the limiting factor in plumbing size.

Ted

 

[TheLake]

I did a bunch of research. We are live a boards and primarily at dock. I decided on the Scala 2 (the 115V version). I do have a very good (new) Multiplus inverter that I can use to run the pump while away from dock.

I have read reviews and other posts on this forum where other members have gone this route and are quite happy with the results.

I plan on using 3/4" up to the manifold and then 1/2" to the taps.

I don't get the idea of the check valves on the lines from each water tank. Aren't check valves to prevent backflow? And if so, why would I care if some of the water from the tank flowed back into the tank?

I like the idea of a "whole house" filter system by the pump in the engine room. Would you put it in right before the manifold (after the pressure gauge, pressure limiter, and check valve?). Any concerns with reduced water pressure due to the whole house filter?

Chris

 

[Nickwadsley]

Check valves prevent it airlocking between the pump and the tanks and the pump always has water behind it to start pumping
I re plumbed my boat in a not to dissimilar arrangement this year and I added a prime loop at the manifold and a drain off the manifold

 

[HopCar]

Is the surge arrestor to stop water hammer? I don’t remember ever seeing one on a boat but I don’t know why not.

 

[tiltrider1]

If you have a 2500 watt inverter then I see no reason not to us an AC pump. I will say, I have never experienced a motor failure on a FW pump. What I see failing are tHe pumping mechanism, especially membrane pumps. This is why I have changed to a screw style pump.

Now my hydronic heat system uses a Grundfos AC pump and it has been working for 30 years.

 

[O C Diver]

I did a bunch of research. We are live a boards and primarily at dock. I decided on the Scala 2 (the 115V version). I do have a very good (new) Multiplus inverter that I can use to run the pump while away from dock.

I have read reviews and other posts on this forum where other members have gone this route and are quite happy with the results.

I plan on using 3/4" up to the manifold and then 1/2" to the taps.

I don't get the idea of the check valves on the lines from each water tank. Aren't check valves to prevent backflow? And if so, why would I care if some of the water from the tank flowed back into the tank?

I like the idea of a "whole house" filter system by the pump in the engine room. Would you put it in right before the manifold (after the pressure gauge, pressure limiter, and check valve?). Any concerns with reduced water pressure due to the whole house filter?

Chris

Regarding water filters:
If there is an accumulator or separate pressure switch, they need to be before the filter. I would put it before the pressure reduction valve. The cartridge and housing is larger than what you may be visualizing. The cartridge is 20" X 4", is a 10 micron carbon block style that removes chlorine, odor, and VOC.

https://www.discountfilterstore.com/c2-02-viqua-carbon-whole-house-filter.html

This is the housing I have:

https://www.discountfilterstore.com/water-filter-whole-house-pentek-hfpp-pr20.html

Ted

 

[STB]

I did a bunch of research. We are live a boards and primarily at dock. I decided on the Scala 2 (the 115V version). I do have a very good (new) Multiplus inverter that I can use to run the pump while away from dock.

Hey Chris,

That makes a lot of sense. When I looked up the pump I just found the 208v - 240v version and that seemed hard to support underway. 115v makes sense, especially with an inverter available. Happy plumbing!

 

[Bacchus]

Looks good...
Don't you want the Press Gauge after the Press Regulator / Limiter to set/check on the desired operating Press.?

 

[O C Diver]

Looks good...
Don't you want the Press Gauge after the Press Regulator / Limiter to set/check on the desired operating Press.?

If you're building new, I would want one on both sides. Having one on the pump side allows you to diagnose suspected problems and make sure the pump shuts off at the desired pressure. Having one down stream of the pressure regulator allows you to set the regulator. Ideally, have the water flowing at a faucet whe setting the regulator as flow pressure will be different from lockup pressure.

Ted

 

[Lepke]

Insulate your hot water lines so you get the temp you want at the heads. If you want the hot water to stay hot in the tank, insulate the cold line several feet out. Also add insulation around the tank if you are wanting the heat to last a couple days.
My 50 gal HW tank has 2" of foam all around, top, bottom, sides. Depending on use I can have hot water for 2 days+.

 

[Bacchus]

If you're building new, I would want one on both sides. Having one on the pump side allows you to diagnose suspected problems and make sure the pump shuts off at the desired pressure. Having one down stream of the pressure regulator allows you to set the regulator. Ideally, have the water flowing at a faucet whe setting the regulator as flow pressure will be different from lockup pressure.



Ted

Ted
Good points

 

[TheLake]

Thanks all!

 

[Cartouche]

Hi all,

I am replumbing my CHB 42' trawler.

I am going to use a Grundfos Scala 2 AC pump and pex with a manifold.

I am attaching a diagram. I am considering not having a shore water line hook-up.

I am not sure about the water arrestor...if one should be installed and if it is installed before or after the manifold.

Other thoughts or concerns?

Thanks,
Chris

The only concern I would have using Pex, is it does not come apart easily, the seatech line is designed for Marine use and if you have to bypass a Hot water tank it is easier to take apart and install a bypass tree in.

 

[SIBERNUT]

Shore water

Looks pretty basic. Nothing wrong with that.

I think skipping the shore water hook up is perfectly fine. Shore side hook ups were common back in the 80's when marine water pumps Madeline poor pressure and volume. With modern water pumps I find using shore side hook ups to be greater risk than value.

A cheap garden water limiter can be set to turn off wherever you want for safety.

 

[tiltrider1]

A cheap garden water limiter can be set to turn off wherever you want for safety.

You could. Sounds Mickey Mouse. I will stick with a quality 10 gpm FW pump.

Wouldn’t trust it anywhere that has freezing weather.

 

[Comodave]

The only concern I would have using Pex, is it does not come apart easily, the seatech line is designed for Marine use and if you have to bypass a Hot water tank it is easier to take apart and install a bypass tree in.

On our last boat we had a permanent bypass installed. Turn 2 valves and pull a drain plug and it would empty.

 

[IWAB]

What PEX tubing do you plan to use? PEX -A or PEX - B for your project?

 

[IWAB]

And for anyone else that has replaced old fresh water plumbing with Pex, which did you use? PEX A OR PEX B?

 

[PhilPB]

And for anyone else that has replaced old fresh water plumbing with Pex, which did you use? PEX A OR PEX B?

I just completed redoing our complete plumbing system and used Pex-A. Very pleased with it's workability. I also bought the Milwaukee Pex-A expander tool, made the job much easier. A few of the best reasons I used A over B is:
1) the connections for Pex-A do not restrict the flow as the id of the connectors are the same as the pipe
2) After expanding the pipe and collar, you have about 15 seconds to maneuver the pipe and connector(s) to get the perfect angle and fit
3) In tight spaces there would have been no way a crimp tool would fit to make the connection. With Pex-A, you can pull the pipe to a space to expand the pipe and then move it to where the connector is...again, you have about 15 seconds of play time

 

[twistedtree]

I just completed redoing our complete plumbing system and used Pex-A. Very pleased with it's workability. I also bought the Milwaukee Pex-A expander tool, made the job much easier. A few of the best reasons I used A over B is:
1) the connections for Pex-A do not restrict the flow as the id of the connectors are the same as the pipe
2) After expanding the pipe and collar, you have about 15 seconds to maneuver the pipe and connector(s) to get the perfect angle and fit
3) In tight spaces there would have been no way a crimp tool would fit to make the connection. With Pex-A, you can pull the pipe to a space to expand the pipe and then move it to where the connector is...again, you have about 15 seconds of play time

I agree with all the above, but they are really characteristics of an expansion fitting system, not PEX A per se. PEX A is required for expansion fittings, but it can be equally used with a compression fitting system.

I’ll also put in another plug for an expansion system. It’s my favorite overall, and especially on a boat because of access restrictions, and because there are no metal bands involved that could rust over time.