Spectra Watermaker Feed Pump Vertical Lift?

[Chotu]

Originally Posted by 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.

Exactly. That’s why it’s going on the bridge deck. So it can be easily accessed, serviced and operated.

The thing that really gets me is all I have to do is buy a Rainman water maker which can do everything I want out of the box, without modification.

So there’s got to be a way to make the spectra I already have work.

I had thought we already arrived at the solution but there sure are a lot of posts on this thread today pulling the thread backwards.

[mitiempo]

Originally Posted by mitiempo

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.

As I posted

[Fuss]

Every millimeter more above the waterline a watermaker is installed, feed pumps included, the more unreliable it all becomes.

[GRIT]

Here's a thought.

Brass or bronze 3/4" pipe, with 90 degree elbow, mounted like an upside down periscope in the outboard well. Or, a through hull in the outboard well.

Then, bring the pipe a foot above the waterline, to another 90 degree elbow, and through the bulkhead (bonded to the bulkhead). Now mount a hose barb, and attach your pumps to that pipe, a foot above the waterline. The output from the pumps can travel quite far, but the inlet should be closer to the "through hull". I'd mount the pumps slightly lower than the through bulkhead fitting, as a siphoning effect will help to lower the "head". You could mount the pumps at the waterline, and once you get the air out of the pipe, it'll stay filled with water.

Now you can make water any time. The through hull isn't "in" the boat, and the "periscope" facing forward, means you can make water underway too.
You may want a grille on the forward end of the "periscope".

You'll have to find a way to secure the pipe to the bulkhead. Maybe some clamps. You can seal the pipe with expandable foam, to the hole in the bulkhead, then glass it with poly. If you can get the boat to the east coast of Fl this winter, I'll bog/glass it for you, using epoxy.

Thoughts? You'll have to have your girlfriend cut the hole with a holesaw, but I'm sure she can do that. It should be an "epoxy free" installation.

Cheers.
Paul.

[Chotu]

Originally Posted by Fuss

Every millimeter more above the waterline a watermaker is installed, feed pumps included, the more unreliable it all becomes.

Except Rainman which has zero problems lifting to 2 meters.

I just talked to Ron over there about the problem.

Rainman, with no modifications, easily lifts 2000 millimeters right out of the box.

If this isn’t going to work (as the internet now says after providing a solution already in this thread), I’ll just sell the spectra and get a Rainman.

[Chotu]

Originally Posted by GRIT

Here's a thought.

Brass or bronze 3/4" pipe, with 90 degree elbow, mounted like an upside down periscope in the outboard well. Or, a through hull in the outboard well.

Then, bring the pipe a foot above the waterline, to another 90 degree elbow, and through the bulkhead (bonded to the bulkhead). Now mount a hose barb, and attach your pumps to that pipe, a foot above the waterline. The output from the pumps can travel quite far, but the inlet should be closer to the "through hull".

Now you can make water any time. The through hull isn't "in" the boat, and the "periscope" facing forward, means you can make water underway too.
You may want a grille on the forward end of the "periscope".

You'll have to find a way to secure the pipe to the bulkhead. Maybe some clamps. You can seal the pipe with expandable foam, to the hole in the bulkhead, then glass it with poly. If you can get the boat to the east coast of Fl this winter, I'll bog/glass it for you, using epoxy.

Thoughts?

Cheers.
Paul.

Sounds pretty good, Paul. The only issue I have is my fuel tanks occupy the area where you are proposing to install the feed pumps and Pre-filters. There is no space forward of the bulkhead down in the bilge . The space is up at bridge deck level.

But maybe something similar to this would work. Just arranged a bit differently. I appreciate the offer on the epoxy, but don’t worry about that. LOL.

[GRIT]

Darn it! I thought I had it all figured out.

Well, I'm pretty sure you won't have trouble selling the Spectra unit.
That should fund the rainman.

Cheers.
Paul.

[RaymondR]

I have not studied the Clarke pump on the Spectra however it sounds like what is called an "intensifier" driven by two small positive displacement, multi cylinder diaphragm pumps.

An intensifier generally consists of a number of parallel intensifying units with a directional control valve supplying fluid to large piston in a cylinder which drives a small piston in a cylinder with suction and discharge valves. I surmise that the Clarke pump also has a pressure recovery piston which is fed by the discharge from the membranes to recover energy from the waste water discharge and hence it's high efficiency.

Consequent to it's construction the Clarke pump will just run faster or slower depending on it's feed water supply with no detrimental effects because of varying feed water quantity.

However ot is a different matter with the positive displacement feed pumps as the diaphragms of these are driven by an electric motor and if the diaphragm chamber is not filled properly on the suction stroke water hammer will occur on the discharge stroke which causes over-stressing of the diaphragms and subsequent early failure of the diaphragms. It is this water hammer effect which limits the amount of suction lift these pumps can tolerate.

The usual solution to water hammer in positive displacement pumps is to pressurize the suctions and on larger pumps a pulsation dampener is also installed a close under the suction valves as possible.

Using a lift pump and the T arrangement to provide a slight positive pressure on the suctions should lead to an increase in their efficiency and a lessening of the wear of the pumps and consequently it would not be a bad arrangement to have even if the charge pump suction was vie a through hull.

[Fuss]

Originally Posted by Chotu

Except Rainman which has zero problems lifting to 2 meters.

I just talked to Ron over there about the problem.

Rainman, with no modifications, easily lifts 2000 millimeters right out of the box.

If this isn’t going to work (as the internet now says after providing a solution already in this thread), I’ll just sell the spectra and get a Rainman.

Perfect, sell the spectra to someone on here for a good price and buy the rainman from Ron.

[Chotu]

Originally Posted by Fuss

Perfect, sell the spectra to someone on here for a good price and buy the rainman from Ron.

That may be the route if it’s impossible to supply the spectra with intake water at like .5psi.

I have no idea how supplying water at nearly 0 psi to a height of less than 2 meters (5ft) became such a technological impossibly.

If it continues to be impossible to raise water less than 2 meters (5ft) at .5psi, I’ll trade the spectra for a Rainman or sell for an equal price.

[Fuss]

Originally Posted by Chotu

That may be the route if it’s impossible to supply the spectra with intake water at like .5psi.

I have no idea how supplying water at nearly 0 psi to a height of less than 2 meters (5ft) became such a technological impossibly.

If it continues to be impossible to raise water less than 2 meters (5ft) at .5psi, I’ll trade the spectra for a Rainman or sell for an equal price.

Every millimeter more above the waterline a watermaker is installed, feed pumps included, the more unreliable it all becomes.

[Chotu]

Originally Posted by Fuss

Every millimeter more above the waterline a watermaker is installed, feed pumps included, the more unreliable it all becomes.

Unless you buy a Rainman which lifts 6feet (2000mm) without a second thought.

So why is it technologically impossible with a Spectra?

Also, I’ve rarely seen a water maker installed in a bilge. It’s usually on the wall in an engine room or something where you can stand there and work with it.

[mitiempo]

Originally Posted by Chotu

Unless you buy a Rainman which lifts 6feet (2000mm) without a second thought.

So why is it technologically impossible with a Spectra?

Also, I’ve rarely seen a water maker installed in a bilge. It’s usually on the wall in an engine room or something where you can stand there and work with it.

With the feed pumps mounted lower.

Spectra is more efficient than any other watermaker. If you don't care about efficiency (amps/gallon) the pumps can be different.

I have 8 through hulls and there is not an issue if they are properly done.

I certainly wouldn't worry about one if it allowed a watermaker to run properly.

[waterman46]

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.

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.

Again, you don't need a lift pump. The feed pump is easily capable of priming. Why don't you simply try it before wasting time figuring out how to provide water using another pump? Having to use a second pump just will cut the efficiency terribly. And if you do that, you'd have to have a reservoir to receive the output of the additional pump, with an overflow tube near the top, not just a Y valve. At bottom of reservoir would be your outlet to the input of the feed pumps.

Yes, do dump the output of the feed water down low. In theory it will improve the flow rate. You'd probably want to dump it low anyway.

If you have feedpumps with higher volume capacity, those won't damage the Clark pump. Set the pressure switch on your feed pump max pressure, with feedpump output totally blocked, to 120 psi. That protects the Clark pump in case it gets stalled.

The Clark pump part that receives the feed pump flow is basically a couple of cylinders with valves controlling when the water flows into and out of them. The valves control the cycling of the piston that drives high pressure water into the membrane housing. Those valves will switch to the next cycle whenever the cylinder reaches end of travel. Higher feed pump water flow will just make that happen sooner.

I have been using my Spectra 380C since 1997. It works great, but the Clark pump has needed a rebuild twice due to cracks in the housing. I guess that's not to bad, 10 years between service. Replaced the feed pumps once also. In my installation they have to suck water 20 feet from the forward part of the boat, then up 3' to the feed pumps in the engine room. They prime very quickly, even after I have drained the 20' feed line to keep it free of marine growth during long storage.

[waterman46]

Originally Posted by Chotu

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.

I often run my Spectra watermaker, for flushing, with the output of my fresh water onboard system, which is pressurized, going to the input of the feed pumps. That extra 15 or so psi on their input causes no problems with the feed pumps.

The only feedpump problems I have had in 20 years have been corrosion of the motor due to salt water spraying on it (leak at the hose clamped outlet tube).