As of six months after the Space DLC launch, steam seems to work similar to before the update. Open loop systems are still busted and require 100x more fresh water than before. There is no more black smoke and no more boiler explosions.
Add one feature, remove two.
Way to go.

Keep your heat source (furnace/firebox/reactor) around 130°, this will keep the boiler at ~110°.

Pumps are no longer necessary between heat source and boiler, they can speed up the heating up process significantly (48s with large electrical pumps vs. 71s without pumps for a reactor->boiler setup).

Boilers now hold 175l of steam and fresh water combined. If you've already got 175l of steam in the boiler, fresh water won't be able to enter.

Ignore the boiler pressure readout, it's of no importance, same for the fluid volume.
Use the advanced tooltip or a pressure sensor on the steam output to read steam pressure. If the steam output pressure reaches 60atm your boiler is running at maximum output.
Most of the time the cap will be ~58atm. I've only managed to hit 60atm using a large electrical pump.

Turbines are now best hooked up in parallel, the pressure buildup happens way faster.
Hooking them up in series is not recommended since you'll get barely any pressure after the 4th in series, even with pumps.

If your steam setup runs at less than 60atm steam output pressure from the boiler and your condenser is below ~90°, then you might need to add a fresh water tank behind a fluid relief valve on the boilers fresh water input.

This will be the case when having lots of turbines (12+) or lots of chained steam piston sets. Each fluid connection takes up 5-10l of steam to fill the internal buffers, so past a certain point you need to add more fresh water.

Ignore the fluid volume readout of the boiler, steam output pressure is all that matters (as mentioned above). Once you added a fresh water tank the pressure output should rise towards 60atm again, if you have lots of steam turbines or multiple steam piston sets.

For some time now I've built a variety of steam setups, with all of the available heat sources.

With the major oil update, heat sources now are the nuclear reactor, 2 fireboxes, diesel furnace and the electrical furnace. Aside from the used fuel, the heat sources are identical in function and it boils down to a few important things to watch out for further down the line, which I will cover in this guide.

Unfortunately steam turbines are still in a weak chested state right now, despite the developers buffing their power output. They are useable for direct drive but shouldn't be used for turbine electric systems because the power output is even less efficient than going diesel electric (yes, it is THAT bad).

They require both lots of space, and buoyancy, since all the components are huge and heavy, with a power output a wee bit less than a medium prefab diesel.
For example a large prefab diesel is able to pull ~380 output of a large generator, while a single turbine in an optimal setup reaches ~160. This makes the large prefab diesel ~2.3x stronger than a single steam turbine for 100 less mass (not including the heat source/boiler/fuel container mass.

For the remainder of this guide you can treat firebox/reactor/diesel or electric furnace as interchangeable, since they serve the same purpose.

The oil update introduced diesel and electric furnaces, and changed the large/small firebox to no longer spawn with any coolant. If you directly connect your boiler with any of the furnaces/firebox you now no longer need coolant, once the firebox reaches ~130°+ the coolant flowrate will rise on its own, pumps are still mandatory to maximize heat transfer and coolant flowrate.

The fuel consumption of the diesel furnace is on the lower end of things when powering a boiler, making for a very decent heat source due to the convenience of refuelling diesel vs. coal, while the electric furnace is basically an infinity generator.

A single electric furnace on a single medium battery is enough to get the boiler to 100°, from that point you're set.

You need a single heat source, single boiler, a single condenser and as many turbines as you can fit.
Make sure every pipe connection is pressurized by using electrical pumps.
Turbines can be stacked in series, with large electrical pumps for the steam.
Pistons can also be stacked in series, to make one of the most powerful/efficient ways to power any vessel if you have the space.
Pressurizing all the pipe connections is mandatory, otherwise you're likely to run into a bottleneck / not at full capacity.

Coolant Pumps:


The way it currently works is that the pressure will increase, the more steam is inside the boiler.
The rate of steam generation per second also increases with temperature.
You can calculate steam volume of a boiler in liters by multiplying pressure by 70.
Once the pressure is above 10, the boiler will explode.
Boiler pressure on its own doesn't move much of the steam, you're better off using large electrical pumps to push the steam through your pipe network.

Set it to 100%.
There are plenty of folks still parroting to set it to something like 2-4%. It might work in a few cases, could cause your entire steam system to stall if you have lots of turbines/pistons and was just meant as a quick fix for exploding boilers, back when the water to steam conversion ratio has been increased. If you follow the rest of this guide this won't be an issue.


No one wants them, steam everywhere and you might end up stranded or worse, as dinner for the Kraken.

Luckily they're entirely avoidable by using 2 threshold gates and an AND gate.
As long as your firebox/reactor is sitting at the recommended values mentioned above this works like a charm.

Place two threshold gates and connect each to boiler pressure and boiler temperature.
Set the pressure gate to min:0 and max:5, the temperature gate to min:0 and max:110.
Connect both outputs to the AND gate, and the AND gate should be connected to the pumps delivering the hot coolant from the firebox/reactor to the boiler.

This way the boiler will only receive hot coolant if it's below 110° AND below 5 pressure.
It also is beneficial for the condenser, since the steam reaching it will be at most 110° hot, making it easier to condense back into water.

Logic:
Note that this is just a quick hack to avoid boiler explosions and shouldn't be necessary for a properly setup circuit after following this guide.

The nuclear reactor is by far the most prestigious and complex way to power your steam system.
You can make a reactor with replaceable fuel rods and depending on rod layout, can last a very long time (no hard numbers yet, some players claim to have an approximate runtime of 2k hours with the same set of fuel rods, based on fuel rod change of fuel level, without mentioning either layout or temperature used).

A nuclear reactor uses fuel rods for the reaction, and control rods to keep the reaction in check.
Fuel rods use uranium ingots as fuel source, 9 ingots per fuel rod. It is required to have sufficient in the outpost storage when spawning a vehicle with a reactor in career mode.

Industry DLC owners can mine uranium at the masshole shaft and refine it into ingots at the Uran Wind Uranium Processing Plant on Meier Island, while non DLC owners need to mine uranium ore in the Cavern of Thales, which is an underwater(!) cave on the volcanic islands.

Non DLC owners can only refine uranium ore to ingots in the arctic, at the XFury Uranium Processing Plant in the arctic, which is also a randomized island, so good luck finding that one. Seems to be a deliberate choice made by the developers, forcing players to mine underwater and make a ~240km round trip just to refine uranium when not owning the DLC...

Control rods have some sort of efficiency range, it's best to place fuel rods in a manner where it's touching at least one adjacent control rod.

Reactor Layout:

Control rods need to be placed 3 blocks above the fuel rod assembly base, otherwise they won't be able to control the reaction (can be seen in the example reactor).
Fuel rods need to be inserted into the fuel rod assembly part, in order to start the reaction.

A proper layout of control rods and fuel rods will lead to fast heatup times and high runtime, a low temperature also plays into higher durability of the rods.

A good layout which is tileable and has a high fuel rod to control rod ratio would look like this (top-down view):
This is a single control rod surrounded by fuel rods.

Enhancing this pattern would lead to this layout:
This is already very sizeable and should last a long time.

You could take it one step further and surround the outer control rods with fuel rods, though that seems excessive and will only fit in the largest of vehicles.

Reactor Control:
Depending on layout, you need multiple control mechanisms. In the upper layout, as posted above there's only a single control rod, only needing a single control mechanism.
In the second layout, you have the central control rod, and the outer control rods. The central control rod would be controlled by its own control mechanism, while the outer control rods would have their own control mechanism, which helps keeping oscillations in check.

Here's an example reactor using the second layout:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2978124714
Start with a desired temperature around 160° and reduce it to ~120° once the boiler starts reaching 100°. There's also a MC to mimic Cherenkov radiation.

Radiation:
Radiation starts as soon as the fuel rods connect to the fuel rod assemblies, starting the reaction.
It's tied to the reactor temperature and only the water inside the reactor chamber will get irradiated.
You can make a holding tank of similar volume, disconnect the fuel rods from the fuel rod assemblies using the on/off logic node, and pump the reactor water into the holding tank.
This will irradiate the holding tank as long as the water is inside, while removing all radiation from the reactor chamber. This way you can open the reactor chamber and replace depleted fuel rods.

Fireboxes are your run of the mill heat source, the temperature should be controlled by an air valve, restricting temperature to a level where the boiler stays above 100°, which would be around 130° for the fireboxes.
They are most likely the cheapest way to power your steam system, since coal is free, with the downside of not being able to purchase coal anywhere, hence making it mandatory to have some mining vessels beforehand, if you plan on playing career.

The diesel furnace has a very low fuel consumption, staying at around 130° it will consume 0.1-0.2l of diesel per second at most.
This results in an extremely good range / fuel ratio on top of being more convenient to refuel compared to coal. The noise can be off-putting, however on larger vehicles it's possible to place it outside hearing range of common areas/bridge.
The diesel furnace is currently the most convenient way to power your steam system, due to being able to buy it at a rather low price, on top of the easy refueling compared to coal or nuclear reactors.

Official infinity generator? Mayhaps.
Jumpstarting the boiler? Within 25 seconds.

The apparent lack of testing (or at this point apathy) from the devs regarding game balance allows for the electric furnace to jumpstart a boiler from a single medium battery and, using steam pistons, allows for an infinite power generator without resorting to glitches/exploits.

Remember back when electric motors and generators got nerfed to hell and back? The electric furnace makes all the previous attempts to keep infinity generators out of the game a moot point.

For regular uses on bigger vessels I can heavily recommend to use up to 6 electric furnaces in series to quickly heat up a boiler, then switch to a diesel/firebox or reactor to keep the temperature up.

There are diminishing returns when using more than 6 electric furnaces so I'd suggest this as a limit, should take around 20-25 seconds from ignition to steam being produced in most setups, depending on coolant flowrate.

Due to the furnaces not spawning with coolant, I recommend adding a medium prefab tank of freshwater, set to 30% to fill up the 6 electric furnaces with coolant to keep the flowrates going.

The Electric furnace seems to be an official infinity generator, since you can easily generate more power than a single furnace consumes. However this is a quick way to drain all the (remaining) fun out of the game, so I suggest using the electric furnace as a refinery heater or a way to jumpstart boiler steam production.

Keeping the heat source temperature as low as possible helps to keep fuel consumptionr down and also helps the condenser to condense the steam back into water, so it can be used again by the boiler.
Good values are ~130° around sawyer and ~140-150° around the arctic regions, depending on distance between boiler and heat source, since longer pipes give bigger temperature losses.
Since the boiler temperature will mostly be 15-20° lower than the heat source, the boiler should be around 110° for sufficient steam production (except for steam train wheels, more details in the specific section).
Controlling the heat source temperature depends on which one you are using.
The reactor works best when controlled by a dedicated PID, controlling change of temperature per second using the control rod insertion node.
Fireboxes and Diesel furnace can be controlled by using a variable fluid valve on the air input (best with a pump before and after the valve to maximize flowrate during heatup).
The electrical furnace can only be toggled, so a basic threshold gate will do, added together on an AND gate with a key or toggle button, in order of being able to turn it off.

Firebox example with pressurized air+exhaust pipes and an air valve to control the temperature:

Using a single condenser should be all you need, paired with 2 small electrical pumps and a 5x5 radiator this will be able to handle your steam to water conversion.
Once the condenser receives steam, and its temperature is below 100° it will condense steam back into water. The conversion rate is low, the tooltips won't properly show any flowrate due to rounding errors, the only sign to tell you it's working is the negative sign in front of the condensers water output tooltip.

If it's negative, it's putting out water.

Components that are connected through pipes have an internal buffer, which needs to be filled first until flow can happen. For most components this has a volume of 5-10 liters, so it will take a while to fill up until the boiler sees any water input (usually 15-20 minutes).

An open loop steam setup would vent the steam after it has been used.
This can best be done with pumps to quickly get rid of the steam to guarantee flow throughout the system and prevent steam clogging up the pipes, due to boiler pressure alone not pushing steam as much as it should.
Make sure you have a fresh water source to provide more water for your boiler, you can determine the water consumption by using a delta block from the MC editor, connect the input to the boilers water volume and multiply the delta block output by 60, to get water consumption in liters per second. Now divide your water volume by the consumtpion rate to get how many seconds of water you have:

It's important to pressurize the condensers connections.
There should be one electrical pump at the steam input and one for pumping the condensed water back into the boiler.
Small electrical pumps will do fine here, for the water outlet I've also successfully ran a small impeller, powered by a small motor, with the condenser fluid volume used to control the motors throttle 1:1.
Works like a charm and due to the tiny water amount inside the condenser it won't eat up meaningful electricity.

For the cooling you can use a 5x5 radiator with small electrical pumps for the connections or direct sea water if you're not in a submarine.
If your boiler is set up with the logic mentioned above, the steam should be at 110° at most, giving the condenser an easy time condensing it back into water.
Of course you can use any other means of cooling for the condenser, the 5x5 radiator was just an example. Condenser cooling seems to be a flavor at most, since it will most of the time stay well below 80°, following the tips in this guide.

Condenser connections and cooling:


Desalinators were basically useless with their implementation, a recent update made them useful however.
The functionality is pretty straightforward, use a large electrical pump to feed salt water to the input side, and another pump to retrieve it from the output side.
Desalinators will now reach a flowrate of 0.2l/s, allowing a group of 6-9 desalinators to replenish your fresh water supply faster than you can vent it out of your turbines/pistons.
A single large electrical pump can supply up to ~375 desalinators, so for practical purposes you should never need more than a single pump for input and output.
If you want to go wild and need lots of fresh water quickly, here's a desalination plant in container format:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2965697553
Flowrates are 30-45l/s of fresh water output, depending if you pressurize your hose with a large pump as well.

1:100

For every liter of fresh water, the boiler will generate 100l of steam.

1:70

For every unit of pressure, the boiler will hold 70l of steam.

For the small firebox multiply its temperature with 0.88 to get a rough estimate on coal / hour.
For the large firebox multiply its temperature with 0.85 to get a rough estimate on coal / hour.

To fire up your large or small fireboxes you need coal.

The hotter a firebox gets, the more coal it consumes. This is rather straightforward to measure though albeit differently done than your typical fuel consumption for diesel/jet powered engines.


Here's the coal consumption of both fireboxes, measured in coal/hour at a set temperature:


To control the temperature of a firebox you want to put a variable valve on the air input, followed by a large electrical pump to provide plenty of pressure so it heats up faster.
This is also one of the most typical usecases for a PID.



At 120° your large firebox will consume ~103 pieces of coal per hour. Which means 1000 coal will last you roughly 10 hours.

The large firebox should be your go-to option. It's more efficient in producing heat per coal consumed and is able to double down as a heater, even in the arctic.



I'd only recommend the small firebox for vehicles that have extreme space restrictions.
It is slower to reach the target speed, consumes more coal for heat produced and is not fit to be used as a heater in the arctic, since it has to run at ~168° to barely reach 5° ambient temperature. If you step further than 3m away you'll freeze again.
Maybe this was an oversight by the devs.

Use large electrical pumps on the steam turbines.

Impeller pumps are inefficient and eat up lots of engine torque if not properly geared down, combined with the already low power output of steam turbines this makes for a non recommended setup.

Once pressurized, the flowrate (visible with the advanced tooltip enabled in the general settings) will cap out at 1.8l/s. You won't get more out of the turbines, that's their peak and roughly equal to the medium prefab diesel.

To get the most out of this system you also need multiple turbines. Chaining them up in series as seen in the following picture yields the best flowrate stability, due to how the games fluid system currently works.

Powering a generator isn't advised, better use the turbines as direct drive.

To get power out of them you can easily gear them below 1-2 RPS, which also reduces the noise.
Since there is no torque loss with low RPS this is recommended to get as much power as possible out of the turbines.

Steam turbine pump layout:

This is an example on how to get the most out of steam turbines, using a PID to control the firebox air valve, taking all the tips of this guide into account and should showcase how a steam turbine setup powered by a firebox would look like.

https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2835120236

Feel free to play around with it, take a look at how the PID is setup to control the air valve of the firebox.
At 130° you'd see the firebox consume around 110 coal per hour.

Pistons are rather straightforward to set up and offer some decent power compared to turbines.
You need at least 2 pistons to get going, otherwise you risk getting your single piston stuck in deadlock with no way to overcome it.
From my testing so far I haven't seen any advantages to timing the piston steam inputs, the performance difference was well within 2-3%.

With stiffer timings this value goes up, with the risk of stalling the pistons.
Since you can have multiple steam piston engines chained in series, you'll have power to no end anyway.

To get some power out of the pistons you want to gear them down. They typically don't spin faster than 1.5 RPS so you might need 5-6 1:3 gearboxes with the blue arrows facing the pistons to max out their torque.

For a single steam piston engine you don't need any pumps on the input side.
Splitting the boiler steam output into multiple pipes straight to the piston inputs works just as good. I'd advise on having at least a single large electrical pump on the output side to help increase the pressure difference between input and output, as well as pushing the steam back into the condenser.

The pistons seem to provide the most output at around 0.8-1.5 boiler pressure, even with pumps after the boiler, for some reason temperature doesn't play into it.
I've tested the pistons with 40° ambient temperature as well as regular 18° with both versions receiving 110° steam as well as cooled down 50° steam,
The difference was within 2-3% and seems negligible.

Pistons should be offset from one another, as mentioned above, you'd need at least 2 pistons to get going, 3 are preferred for a smoother RPS output.

If you have multiple pistons you can set up the offsets as seen below, as long as some pistons aren't deadlocked in the extreme points of movement the engine should start moving.

The offsets of neighboring pistons doesn't seem to matter in terms of power output.
For some reason the devs use a slider (*sigh*) with 2 decimal places precision for allowing the player to input the offsets.
With multiple pistons you might want to edit the vehicle .xml files and enter the offsets by hand, if you prefer higher precisions. Just search for
in the vehicle .xml file and enter more precise values by hand. Make sure to back up your file first, in case you mess something up.

For getting appropriate piston offsets you can use the calculator I've linked in the tools section of this guide.

If you want to use 2 pistons due to space constraints use 0.25 and -0.25 as offsets, however I recommend to use at least 3 pistons for a smoother power output.

For 3 or more pistons, you can calculate proper offsets by dividing 1 with the amount of pistons, then multiply this value in an oscillating manner, keep the offset for the first piston at 0 and set it as offset for the second piston onwards.

Example for 3 pistons:

You can also set up powerstrokes and have pairs of pistons at the same offset, here for a 6 piston setup:
Give it a try!

You can reverse pistons with 4 on/off or variable valves, comes in handy if you want to reverse without using a gearbox for authenticity.
Note that the manual valves reduce the flowrate a bit, so you might need to add pumps before and after the valves to mitigate this a bit.
The example on how to set up those valves is linked in the Steam Piston Example section of this guide.

For some reason I'm unable to push the large pistons past 7k output from a large generator.
I was hitting this limit at 5 pistons, with a 12 piston setup there was no increase in output.
Seems to be some hidden torque limit or similar.

If you think you've found a way to get more out of the steam pistons in terms of power output feel free to share your insights in the comments if you're sure to have achieved it without the usual flywheel/clutch exploits/glitches.

Similar to the turbine example, but with medium pistons instead of turbines.

https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2843709793

Here's an example on how to reverse the crankshaft rotation direction of a steam pistons engine:
Activate both forward valves (handle in green color) for forward rotation (red handle valves need to be deactivated) and do the opposite for reverse direction (green handles off, red handles on).

https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2857082017

The steam wheel pistons have been improved quite a bit, I managed to get the large wheels up to 220km/h on the locomotive alone.

The medium wheels seem to be a good fit for passenger trains and the small ones are more of a flavor thing due to their limited speed, don't expect to break any speed records with those.

The large ones bring a good chunk of torque and are capable of hauling my heavy duty ore testbed with no issues, up to 110km/h:



This ore waggon can hold 8641 ore and has an empty weight of a whopping 21429 mass, for a total filled mass of 30070.

Note that there's no way to power the waggon wheels or control traction, which is the most important thing for longer/heavier trains.
Unless you want to pull more than 2-3 waggons, the steam train wheels should work reasonably well now.

To further prove that the 1x piston, 2x wheels layout seems to be the most efficient in terms of traction/torque, I've set up another testbed, with 4 large wheel pistons on 2 wheels each:

This allowed for a top speed of well beyond 300km/h and should give similar results in terms of hauling capacity:


Similar to the other steam propulsion methods, pumps can give you an edge and help maximizing the power output, pressure seems to add to it as well for the steam wheel pistons.
Note that it's possible to get the train moving without pumps for the steam, however this comes with a 25-30% reduction in torque, even with the boiler on full blast at 9.9 pressure.

So far the best performing layout I've found to be 1 piston for 2 wheels and have multiple of those and piping the steam through both sides of a piston in series for maximum flowrate and pressure.


Here's the first piston in the example layout, note that the directional valves are only for visual aid and should not be used in this case.

The blue line represents the steam straight from the boiler, heads into a large electrical pump and into the left hand side of the piston.
The red line moves the steam to the other side of the piston, the pump helps keeping flowrate and pressure at a maximum.
The green line goes to the next piston in series and will receive pressurization by another pump, further down the line.


Here's the second piston from the example layout and basically a mirrored version of the first one.
Steam enters the right hand side of the piston as seen by the blue line, moves to the opposite side by the red line and towards the next piston in series with the green line.

Contrary to the engine pistons, it's NOT possible to reverse the steam train wheel pistons by pumping steam into the output side and out of the input side for some reason. The only way is to use the reverser logic node on the piston part.

Currently steam turbines remain to be a novelty, rather than using them in vehicles that serve an actual purpose in game. The components are simply way too huge, heavy and cost lots of buoyancy regarding ships compared to their meager power output.

For cargo/fluid transporters there are better propulsion methods out there.

Making replicas of steam ships using turbines works fine, seeing how most of these ships were rather slow in terms of speed. Don't expect them to haul containers or fluid amounts comparable to vehicles using other methods of propulsion.

If you want to haul cargo and/or high waggon counts then there's no way around using either turbines or better the steam engine pistons, since those have the highest power output, don't expell steam as fast as the steam wheel pistons and don't lose speed/traction with higher mass as the steam wheel pistons do.

I might add a section for it if wanted, there's already other guides covering reactors and the layout of fuel rods/control rods.

Boiler pressure could be a thing, managing it to stay as high as possible should reward the player with copious amounts of power, contrary to how boiler pressure currently works in game.

I hope this guide was of help and that you'll enjoy goofing around with steam as much as I did.

https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2837732199

Basic Calculator that shows recommended piston offsets.
Simply input the number of pistons and set their offsets according to the calculator output.