Watermaker

Currently this build requires various parts from Schenker Zen 30 (most of the parts, to be frank).

The designs provided here are best suited for temporary (emergency) repairs.  The pressures inside the unit may go up to 100 bar, and if anything explodes, it could damage everything around, including you.  That being said, use these designs at your own risk.  If using these parts and modifications voids the warranty, causes you harm and/or damages your equipment, the responsibility lies on you 🫵.

Energy Recovery System (ERS)

Problems & solutions:

1. Piston X-rings.  These tend to wear out, which leads to nasty noise coming from the clark pump's tubes during operation, as well as low volume of fresh water production, bad output quality, and eventual complete cease of production of fresh water.  Solution: print one yourself!  The design is scaled down 15% from the size that the ring takes after installed on the piston, and it must be printed using a flexible filament (TPU).  The original part is likely https://www.gteek.com/X-ring-59.69x5.33-NBR-70
2. All five carbon fiber tubes have sharp edges, and it often results in o-rings getting cut when the unit is assembled.  One way to improve it is spending a couple of hours rounding and smoothing out the edges of those tubes with a nail drill (35,000rpm ought to be enough, but the more the merrier).  Just make sure not making those tubes shorter than they are supposed to be, only rounder.
3. It's quite difficult to disassemble the unit.  Solution: add 8 nuts paired with washers between Delrin end cap blocks to make it easier to push them away from the core ERS assembly.
4. It's hard to assemble and properly tighten the large nuts that hold the unit together.  Solution: permanently etch thin white lines on all tubes to better see when they're all the way in or not, and make sure the unit doesn't wobble during the assembly process and is completely straight.  A skewed clark pump is likely to create friction between pistons and their tubes, and scratch both of them.
5. The 90º elbow fittings are made out of cheap stainless steel.  A couple of months down the road they'll corrode, with bits and pieces falling off and entering the internals of the ERS, likely scratching the piston tubes, pistons, piston X-rings, etc.  It'll make your unit produce lots of sad noises and never capable of holding over 4 bars of pressure (AKA not function anymore as a desalination device).  I'm currently looking into replacing those fittings with aluminum (6061-T6) or G2/G5 titanium: https://ppcfittings.com/products/90-degree-o-ring-boss-o-r-b-swivel-to-male-an-fittings & https://ppcfittings.com/collections/hose-ends/products/copy-of-show-chrome-plated-swivel-hose-ends-mirror-finish?variant=29040944480367
6. There are three stainless steel G3/8 sealed plugs inside the left end cap, they all corrode.  Solution: attempt to switch to non-metal plugs from here: https://www.jwwinco.com/en-us/products/3.5-Controlling-venting-sealing-of-liquids-and-gases/Threaded-plugs-Sealing-plugs/EN-746-Technopolymer-Plastic-Threaded-Pipe-Plugs-with-NBR-Rubber-Seal

Pump

Just like Spectra watermakers, Schenker Zen 30 comes with a SHURflo 8000 series positive displacement pump (precisely, it's etiher 8000-043-235 or 8008-943-839).

Problems & solutions:

1. It's notorious for 3 small diaphragm valves to break, which results in stunted flow and pressure, eventual inability to produce fresh water.  The solution to that is upgrading the pump with reinforced diaphragms from a different pump model, e.g. https://tweetys.com/shurflo-94-232-06-fresh-water-pump-valve-assembly.aspx (notice the little “cross” in the middle of every diaphragm — that's the reinforcement we're after)
2. The little white check valve wears out and eventually falls out.  Solving this requires a replacement https://www.highpressurepumpsandparts.com/p-36437-shurflo-94-374-08-check-valve-kit-for-8000-series-pumps-santoprene.aspx | https://www.oldhamchem.com/shurflo-8000-series-check-valve-assembly, involves removing the pressure sensor and re-assembling the 5-part mechanism… don't lose the spring!  You can also remove that mechanism from the pump and use an external check valve, e.g. https://www.trudesign.nz/marine/products/69-non-return-valves-check-valves/parts/334-non-return-valve-90804.  It's important to note that  the watermaker is capable of producing water without it.
3. Plastic barb fittings can deform from the heat if the unit operates for a long period of time, and they also take a lot of scratches due to change of hoses and not suitable for handling pressure of overtightened hose clamps.  Replace them with two bronze/aluminum/titanium 5/8" hose adapters with 3/8" male NPT threads, e.g.: https://www.ebay.com/itm/225498132226 | https://www.ebay.com/itm/162046714726 | https://www.alliedtitanium.com/vupdc_Detail.php?UPDCID=1038576001 — just make sure they're long enough to accommodate at least two hose clamps each
4. Changing the pump requires cutting wires.  Mod it to use 2-pin Deutsch connectors, similar to https://www.mniboats.com/BALLAST-KING-W-DEUTSCH-CONNECTOR-316-SS-DRIVE-S-p/190157.htm
5. The fan that comes with it is too small and not waterproof.  Use a 3D-printable funnel adapter and replace it with https://noctua.at/en/nf-f12-industrialppc-2000-ip67-pwm
6. The pressure sensor is vestigial, it only makes the pump more noisy and weigh 30g more, take up more space.  Remove it and use “Watermaker - Pump - Bypass Cover.3mf” to cover the opening, as can be seen on a bypass variant of this pump: https://sprayersupplies.com/8006-543-250-shurflo-a7527350
7. The large 6 stainless steel screws will seize inside the metal base.  Re-assemble the pump covering those screws in something like ASC-I compound: https://www.parktool.com/en-us/product/anti-seize-compound-asc-1
8. The controller box is attached to the pump, which requires below-waterline installation; if anything leaks, there's a risk of that box getting submerged.  Solution: move it away from the pump, reposition close to the control panel.
9. The external pressure switch gets in the way when servicing the pump.  Solution: move it closer to the ERS, ideally where it can't get submerged, or even better — modify the sediment filter to have a thread for that sensor to reduce the amount of hose clamps and barb adapters required for the switch.
10. The motor in SHURflo 8000 is brushed, it's noisy and produces more heat, lives about 4–5 times less than brushless pumps.  It can be replaced with Seaflo SFDP1-018-120-31, or SHURflo 8075 with a voltage booster/regulator, tweaked to match the original pump's flow and pressure.

Raw Water Strainer

Problems & solutions:

1. This strainer has a cylindrical stainless steel mesh (50) that saltwater loves to eat through (especially in high-sulfur-content areas like Florida).  Solution: 3D print own sediment filter mesh screen out of titanium or whatever else: https://www.printables.com/model/670480-sediment-filter-mesh-screen
2. It can be quite hard to untwist it by hand.  Solution: 3D print and use one of these wrenches: https://www.printables.com/model/1202466-water-filter-housing-wrench

Sediment Filter

Problems & solutions:

1. The 5" 5nm filter cartridges need to be changed quite frequently, and they're not cheap.  Solution: buy 10" cartridges for nearly the same price https://mar-nautic.com/5-micron-filter-antibacterial-10-inch and cut them in half.
2. It's hard to ensure the cartridge stays centered as you screw it into the top housing.  Solution: 3D print this bracket and keep it on the filter as you screw it back together https://www.printables.com/model/633237-water-filter-cartridge-bracket

Pressure Sensor

Analog transducer universal for both 12 and 24 voltages.  DPM16 is the name that Schenker gave it, but actually it's a 0–16bar 4–20mA 10–30VDC sensor TR4 by Fox.it, connected using 2-wire configuration.  It ensures that the pressure that the low pressure pump creates is within the range — not too high and not too low.  You can connect the pump directly to your power supply, without using any sensors or electronics at all, but if the pressure gets too low, the pump will just keep pumping water, and if it gets too high, something may explode.  This sensor is what prevents these watermakers from sinking boats.

Problems & solutions:

1. It's expensive, but not overpriced.  In theory, you can find one for half the price or cheaper, especially if you go with something off Alibaba/Amazon.  Just make sure it's 0–16bar and 4–20mA, the voltage doesn't have to be the same, just make sure it matches your power supply.  Kudos to you if you find one with a digital output — more power consumed, but kinda cool for monitoring the system.
2. The screw at the top gets rusty.  Very.  It doesn't seem to be there for regulating anything, it likely just holds the plastic cap with contacts from detaching from the sensor.  I'll try to find something made out of plastic or titanium to make sure it never happens.

Other

Problems & solutions:

1. Threads leak.  Solution: use Loctite 55 pipe sealing thread instead of PTFE tape.
2. Hose clamps rust and fitting connection leak.  Solution: use titanium hose clamps by Titan Marine, Extreme Bolt, Titanium Works, or Mikalor (more info here: https://www.patreon.com/posts/hose-clamps-97245610).