Spectra Watermaker Feed Pump Vertical Lift?

[sail4evr]

Originally Posted by Chotu

Thank you. This is some thing I’m still learning about. So, you don’t think it will be a problem? If I exceed the recommendation by spectra, it won’t damage the clark pump in someway? As in, there will be a fraction of a drop in input pressure to the clark pump? That fraction isn’t half is it? LOL

With a 120 psi pump, if I had to lift it up to 6 feet, will there be a substantial drop in pressure? With that negatively affect the clark pump?

Any extra work being done by the Clark pump will reduce its life or increase maintenance...seals etc. Since it is the most expensive pump...penny wise and lb foolish as they say. And you should ask Spectra because this would effect your warranty.

[Chotu]

Originally Posted by sail4evr

Any extra work being done by the Clark pump will reduce its life or increase maintenance...seals etc. Since it is the most expensive pump...penny wise and lb foolish as they say. And you should ask Spectra because this would effect your warranty.

I agree. I think we came up with the right solution in this thread.

Separate lift pump to Pump water up to a Y fitting at the bridgedeck level.

Install Spectra/spectra pumps at desired bridgedeck level.

One side of Y fitting goes to spectra input.

The other side goes overboard with any excess pressure.

Result is the same intake pressure as installing the entire spectra system at the waterline.

A brilliant solution. I’m impressed with what people in this thread came up with. Grateful too.

[Tupaia]

The downside of this is the ability to use the WM underway. You say you will only use it at anchor but the real benefit is being able to do an ocean passage without setting off with full water tanks (heavy) and making water according to demand. Kind of defeats the object of having a light cat.

[mitiempo]

Originally Posted by Chotu

I agree. I think we came up with the right solution in this thread.

Separate lift pump to Pump water up to a Y fitting at the bridgedeck level.

Install Spectra/spectra pumps at desired bridgedeck level.

One side of Y fitting goes to spectra input.

The other side goes overboard with any excess pressure.

Careful with the "Y". The last thing you want is any air going to the clark pump.

[Chotu]

Originally Posted by Tupaia

The downside of this is the ability to use the WM underway. You say you will only use it at anchor but the real benefit is being able to do an ocean passage without setting off with full water tanks (heavy) and making water according to demand. Kind of defeats the object of having a light cat.

Yes, but how often is this realistically? Boats are at anchor 99% of the time. So, if I really need to do something like this, I will put in a really hard stick that sticks down and holds the thing in place underwater. Or, I could probably tie it off in a way that holds it down as well. It would be weighted too.

[Chotu]

Originally Posted by mitiempo

Careful with the "Y". The last thing you want is any air going to the clark pump.

Definitely. I think the way to do this is to make it go uphill on the exit from the Y. It could go downhill to the spectra input, and uphill to the overboard. That way there is a column of water there to act as a buffer at all times.

[Dsanduril]

If you're going to have a column of water anyway (one foot, half a foot, whatever) then just size the lift pump to provide the right flow with an excess pressure of one foot. Then you don't have the extra plumbing, etc.

If you have a wye, and the lift pump stops producing its rated flow (seaweed on intake?, blown fuse?) then you will definitely suck air into the system at the wye. Without a wye your Shurflo will try to suck water through the lift pump. In this case I don't really know which is worse, air in the system or restricted intake flow.

[Chotu]

Originally Posted by Dsanduril

If you're going to have a column of water anyway (one foot, half a foot, whatever) then just size the lift pump to provide the right flow with an excess pressure of one foot. Then you don't have the extra plumbing, etc.

If you have a wye, and the lift pump stops producing its rated flow (seaweed on intake?, blown fuse?) then you will definitely suck air into the system at the wye. Without a wye your Shurflo will try to suck water through the lift pump. In this case I don't really know which is worse, air in the system or restricted intake flow.

That’s a good point.

Part of the reason people were talking about having the overflow at the Y fitting was to create the correct pressure for the input to the feed pumps of the spectra.

I’m not sure I can create the correct pressure with a lift pump. Can I? Won’t it sometimes be too much pressure?

Asking because I don’t know.

[Ekeno]

Originally Posted by Tellie

The warranty on your Spectra and many other watermaker manufacturers require a dedicated thru hull otherwise the warranty will be voided. Other than that I'd be curious as to why there are no thru hulls in your boat. My reason for asking what kind of boat this is.

Hello Tellie.- I just bougth an Spectra Cape Horn. Which is the optimal size of the intake through-hull and outlet through-hull salt water. Must they have a built-in shutoff valve?
eKeno

[Sailor-Gene]

Originally Posted by Chotu

I have a unique installation for my water maker. I plan to drop a weighted sipping tube down from the bridge deck to make water.

This means my feed pumps for the water maker, I have two of them, will need to pull water up about 4 ft to the bridge deck level.

Are they capable of this? Here is what they look like:

https://www.gps4us.com/SPECTRA-Feed-...BoCfOsQAvD_BwE

The pump you picture is a very good low pressure WATER pump. Spectra utilizes 2 in parallel to increase water volume and pressure through the low pressure side of the Clark Pump... An issue mentioned in a previous response response was keeping the pickup in the water. I lived with 2 pumps with their inputs from a shared seachest and pumps inches above the waterline. If a little bit of air got into the system, the pump became nonfunctional until bled. What is your plan to maintain prime on the pumps during startup?

[Chotu]

Originally Posted by Sailor-Gene

The pump you picture is a very good low pressure WATER pump. Spectra utilizes 2 in parallel to increase water volume and pressure through the low pressure side of the Clark Pump... An issue mentioned in a previous response response was keeping the pickup in the water. I lived with 2 pumps with their inputs from a shared seachest and pumps inches above the waterline. If a little bit of air got into the system, the pump became nonfunctional until bled. What is your plan to maintain prime on the pumps during startup?

The plan, as developed in this thread, is to use centrifugal pump like a bilge pump or submersible sump pump or something, to bring water up to the input for these pumps you have quoted above.

The added advantage of the submersible pump as it will hold the intake down underwater better.

So essentially, a lift pump to get the water to these pumps which feed the clark pump.

Operating procedure would be to turn on the submerged lift pump First, and then turn on the rest of the water maker.

[lituya1617]

Dropping a pickup hose into the water from deck level to avoid a dedicated through hull just seems very much like a farmer is involved in the design somehow. My advice, put in a through hull with a good strainer, and quit worrying about pulling water up a couple of feet. Any positive displacement pump I have ever seen can pull a 4' head without any problem. Who cares what is downstream of the pump as long as it gets sufficient flow and pressure? To protect against a "run dry" situation, you could incorporate a flow sensor cutoff or a pressure cutoff in the line. I do hope this fellow gets some expert advice for his project.

[Chotu]

Originally Posted by lituya1617

Dropping a pickup hose into the water from deck level to avoid a dedicated through hull just seems very much like a farmer is involved in the design somehow. My advice, put in a through hull with a good strainer, and quit worrying about pulling water up a couple of feet. Any positive displacement pump I have ever seen can pull a 4' head without any problem. Who cares what is downstream of the pump as long as it gets sufficient flow and pressure? To protect against a "run dry" situation, you could incorporate a flow sensor cutoff or a pressure cutoff in the line. I do hope this fellow gets some expert advice for his project.

Yet the expert (Tellie) said it can’t pull the water up more than 36” and that’s still not a great idea.

That WAS the expert advice. If you’re an expert and your advice contradicts his, I’m confused.

The boat has design philosophies (don’t know many farmers that have design philosophies, do you?). One of the philosophies is no through hulls below the waterline. The others are: lightest weight possible while still being live able, no zincs and finally: use off the shelf, standard, non marine items wherever possible.

[mitiempo]

Originally Posted by Ekeno

Hello Tellie.- I just bougth an Spectra Cape Horn. Which is the optimal size of the intake through-hull and outlet through-hull salt water. Must they have a built-in shutoff valve?
eKeno

Must be a proper through hull with valve (ball) on the intake. Outlet is above the waterline.

[mitiempo]

One thing I have learned over the years is to follow manufacturers instructions and install the item in a location with easy access for servicing.

As Tellie posted the warranty is void without a dedicated through hull.

I would install a Trudesign through hull with collar and valve. No corrosion problems and not expensive.