Shower Controls -- how they work

[sailandcruise]

As an engineer, I've always been puzzled by the shower controls on Norwegian ships.  Showers on land tend to have a single control that turns them on and adjusts the temperature, or two controls, one each for hot and cold, that allows someone to customize the mix.  But the showers on Norwegian ships have two controls of a different type -- the one on the left controls the pressure and the one on the right the temperature.  I've never understood this until my most recent cruise.

 

 

On this cruise, I inadvertently grabbed hold of the pipe coming out of the wall on the left side and almost burned my hand.  I then experimented by touching the pipe on the right and it was very cold.  (not ice cold of course, then it would have been frozen  )  

 

My conclusion is that the control on the left adjusts the amount of hot water and controls the on/off valve) and that the one on the right adjusts the temperature by regulating the amount of cold that gets mixed in.

 

Now we know.

 

 

[bluesea777]

It's quite simple: see the numbers on the right knob? These are temperatures in *C.

 

Also, see the button on each knob? When you turn the knob, it stops at the button and if you want greater pressure (or hotter water), press the button and turn further.

 

 

[sailandcruise]

12 minutes ago, bluesea777 said:

It's quite simple: see the numbers on the right knob? These are temperatures in *C.

 

Also, see the button on each knob? When you turn the knob, it stops at the button and if you want greater pressure (or hotter water), press the button and turn further.

 

 

Yes, using the shower is quite simple.  It's clear what the controls affect and the user interface is intuitive.  But the actual underlying mechanism isn't that simple; How the pressure and temperature are controlled is what I addressed in this post, not how to use them, which is simple and obvious and not confusing unless you're the type of person (as I am) who always wants to take things apart to figure out how they work.

[senseib]

It is a fairly common design in hotels in Europe and Asia.

[don't-use-real-name]

ALWAYS TEST THE WATER TEMPERATURE WHILE OUT OF RANGE OF THE SPRAY

divert it away from you !

 

Then there is the diverter valve that directs the flow of the temperature controlled water to either the

shower head or the hand wand or in some of the deluxe suite cabins a combination of the shower head

and the body spray outlets - egads there is water coming out of the walls at you.

 

 

 

 

[chengkp75]

17 hours ago, sailandcruise said:

As an engineer, I've always been puzzled by the shower controls on Norwegian ships.  Showers on land tend to have a single control that turns them on and adjusts the temperature, or two controls, one each for hot and cold, that allows someone to customize the mix.  But the showers on Norwegian ships have two controls of a different type -- the one on the left controls the pressure and the one on the right the temperature.  I've never understood this until my most recent cruise.

 

 

On this cruise, I inadvertently grabbed hold of the pipe coming out of the wall on the left side and almost burned my hand.  I then experimented by touching the pipe on the right and it was very cold.  (not ice cold of course, then it would have been frozen  )  

 

My conclusion is that the control on the left adjusts the amount of hot water and controls the on/off valve) and that the one on the right adjusts the temperature by regulating the amount of cold that gets mixed in.

 

Now we know.

 

 

 

16 hours ago, sailandcruise said:

Yes, using the shower is quite simple.  It's clear what the controls affect and the user interface is intuitive.  But the actual underlying mechanism isn't that simple; How the pressure and temperature are controlled is what I addressed in this post, not how to use them, which is simple and obvious and not confusing unless you're the type of person (as I am) who always wants to take things apart to figure out how they work.

And your conclusion would be wrong.  The left control is a flow control valve, that stops flow or regulates how much flow you get, out of the mixing valve, not the water supply in, and not a pressure regulator.   The mixing valve is under water pressure at all times. The fact that it is next to the hot water inlet pipe is incidental.  The right control adjusts the water temperature, by modulating the hot and cold supplies.  The fact that it is next to the cold water inlet pipe is incidental.  Every shower mixer valve in the world has a hot water inlet pipe and a cold water inlet pipe, and these need to join the mixer somewhere.  Just as with any mixing valve for a sink or shower, there is also a pressure balancing valve inside the mixer, so that regardless of where you set the temperature control (it really doesn't measure the temperature of the water), if the pressure in the cold water entering the mixer is too low, it will regulate the hot water back as well, to prevent scalding.

 

An interesting note is that the hexagonal device between the mixing valve and the hose to the shower head is a backflow preventer device.  This is something you don't find in your home's shower, but is required under the USPH sanitation requirements for passenger ships.  Since the wet and partially air filled area inside the shower head is a prime breeding ground for legionella, and because you could take the shower head and dump it in the toilet, if the water supply was turned off to that shower, for repairs, and then started up again, contamination could be drawn back into the main water system, so the backflow preventer keeps water from flowing from the shower head to the piping system when there is no pressure in the pipes.

[Outerdog]

How they work for first timers:

 

1. Cocktails (x 9)
2. Attempt to spin knobs clumsily
3. Step into shower to discover buttons
4. Step out of shower
5. Turn hot/cold knobs as at home
6. Blast self with cold water
7. Stupidly adjust both knobs simultaneously like working radio dials until desired temperature is approximated
8. Shower by splashing dispensed liquids all over yourself because you neglected to notice the washcloth
9. Clumsily fool with the knobs again, blast self with cold water
10. Repeat above step until water flow is positively interrupted
11. Process ends

[don't-use-real-name]

6 minutes ago, Outerdog said:

How they work for first timers:

 

1. Cocktails (x 9)
2. Attempt to spin knobs clumsily
3. Step into shower to discover buttons
4. Step out of shower
5. Turn hot/cold knobs as at home
6. Blast self with cold water
7. Stupidly adjust both knobs simultaneously like working radio dials until desired temperature is approximated
8. Shower by splashing dispensed liquids all over yourself because you neglected to notice the washcloth
9. Clumsily fool with the knobs again, blast self with cold water
10. Repeat above step until water flow is positively interrupted
11. Process ends

Please remember to close the PSYCHO curtain on those ships that have the plastic curtain to contain

the red off color residue to the inside of the shower.

 

 

[Turtles06]

24 minutes ago, Outerdog said:

How they work for first timers:

 

1. Cocktails (x 9)
2. Attempt to spin knobs clumsily
3. Step into shower to discover buttons
4. Step out of shower
5. Turn hot/cold knobs as at home
6. Blast self with cold water
7. Stupidly adjust both knobs simultaneously like working radio dials until desired temperature is approximated
8. Shower by splashing dispensed liquids all over yourself because you neglected to notice the washcloth
9. Clumsily fool with the knobs again, blast self with cold water
10. Repeat above step until water flow is positively interrupted
11. Process ends

 

Thank you for a good laugh to start the day. 😀

[sailandcruise]

6 hours ago, chengkp75 said:

 

And your conclusion would be wrong.  The left control is a flow control valve, that stops flow or regulates how much flow you get, out of the mixing valve, not the water supply in, and not a pressure regulator.   The mixing valve is under water pressure at all times. The fact that it is next to the hot water inlet pipe is incidental.  The right control adjusts the water temperature, by modulating the hot and cold supplies.  The fact that it is next to the cold water inlet pipe is incidental.  Every shower mixer valve in the world has a hot water inlet pipe and a cold water inlet pipe, and these need to join the mixer somewhere.  Just as with any mixing valve for a sink or shower, there is also a pressure balancing valve inside the mixer, so that regardless of where you set the temperature control (it really doesn't measure the temperature of the water), if the pressure in the cold water entering the mixer is too low, it will regulate the hot water back as well, to prevent scalding.

 

An interesting note is that the hexagonal device between the mixing valve and the hose to the shower head is a backflow preventer device.  This is something you don't find in your home's shower, but is required under the USPH sanitation requirements for passenger ships.  Since the wet and partially air filled area inside the shower head is a prime breeding ground for legionella, and because you could take the shower head and dump it in the toilet, if the water supply was turned off to that shower, for repairs, and then started up again, contamination could be drawn back into the main water system, so the backflow preventer keeps water from flowing from the shower head to the piping system when there is no pressure in the pipes.

 

Thanks so much for the detailed correction and explanation.  I was hoping you'd provide one.  Much appreciated, as are all your posts.  😀

 

 

[Hotspring]

On ‎12‎/‎31‎/‎2018 at 6:15 AM, Outerdog said:

How they work for first timers:

 

1. Cocktails (x 9)
2. Attempt to spin knobs clumsily
3. Step into shower to discover buttons
4. Step out of shower
5. Turn hot/cold knobs as at home
6. Blast self with cold water
7. Stupidly adjust both knobs simultaneously like working radio dials until desired temperature is approximated
8. Shower by splashing dispensed liquids all over yourself because you neglected to notice the washcloth
9. Clumsily fool with the knobs again, blast self with cold water
10. Repeat above step until water flow is positively interrupted
11. Process ends

This nails it even for infrequent cruisers---except maybe for step 1.    

As complex as this process is, it is really surprising that this information is not available in the cabin to reference.  It is cool to see the whys in this thread.     Now if we can get confirmation that all showers have hoses in all classes.