Riobel - Deconstructed: the thermostatic valve

Deconstructed: the thermostatic valve

[@deedr1234]

Damn, I am getting nostalgic because this used to be my favorite show.

[@brofenix]

Hmm, nice :) Great explanation! I would love to know more about the last part, how the movement of the pierced (?) cylinder, when cold water pressure decreases, then allows more cold water to flow from the thermostatic valve.

[@nixonwasframed]

Nice. Go to 02:55 for the impatient.

[@ralphhardie7492]

Great explanation Thanks

[@AV1461]

What a great illustration and explanation! I wish it had higher resolution. Two things show how old video is : The low resolution of the video, and the "She has no idea..." segway xD. Still it wasnt very clear what allows the temperature of the output to be set by the temperature handle. I believe the thermostat's wax has a set operating temperature (non-variable).

[@giacomo.1574]

awesome

[@deandodd4755]

hi does anyone know what make that shower valve is ?

[@grahamwood4145]

I have one of these Riobel units and need some instruction on getting the cartridge out to descale or replace. I have unscrewed everything I can, including the two grub screws, and can't seem to budge it. I assume that it is a matter of pulling it out but is it possible that a twist is necessary? The cartridge body is plastic so I have avoided using vice grips on it. Any help would be appreciated.

[@ahmada9534]

Problem is in the summer cold water gets really hot. Wlaaah

[@sandrathompson6224]

How do you remove this handle ..there is no hex key hole!

[@Kuhlyedascope69]

this answered my stoned head perfect thankee

[@jimtron66]

Good explanation of principles but I stumbled at 03:20 "The shaft can move up to six tenths of a Millimetre" !? (That's 0.6mm). You're welcome.

[@GwynethLlewelyn]

Aye, that should be more than enough.

[@jimch7045]

Hello, I need get the same thermostatic valve as you show in this KZbin. Any advice where I can buy it? Many thanks

[@marksierra3522]

Most new shower kits should come with one. It's almost become regulation.

[@stephensmith799]

Beautiful idea. Is limescale build up a problem? We live on a ‘hard water’ area.

[@allenlarabie8854]

Stay away from this system. Nothing but trouble unless you have water filtration system in place.

[@stephensmith799]

@@allenlarabie8854 Thanks for the warning🙏

[@paulb3162000]

This was very interesting. I have a follow up question. What if the cold and hot water pipes are fitted the wrong way round. What effects will this have as hot water now enters the front of the cartridge?

[@dejv1111]

I think the water will remain cold, because the paraffin valve will not open the part with hot water.

[@TheCampfireplayer]

@@dejv1111 I’ve had this happen to me this week. It results in an either all cold or all hot situation. The valve tries to correct a too hot situation by introducing more cold, but when the supplies are reversed this adds more hot. The cycle continues until you have all hot. You then have to put the valve fully to the counter clockwise side to put it all cold which bypasses the thermostat giving you all cold.

[@Empireplumbing45]

So having this valve with a circulation pump is not a good idea ?

[@GwynethLlewelyn]

I'm not a plumber, but I would say that a _thermostatic_ circulation pump with automatic adjustment of water temperature probably does precisely the same as a thermostatic valve, so having _both_ installed would be redundant. However, it's worth noticing that the valve uses simple physics and a fully mechanical design to replace a complex system with electric motors, ICs, sensors, and so forth - all of which can fail independently of each other :-) In other words, unless we're talking about a _really_ long pipe to provide hot water at an extremely distant point, my guess is that the thermostatic valve, by itself, would be a much simpler solution; the circulation pump, by contrast, would give instant (or near-instant) warm water on demand on such a long pipe, while the simple thermostatic valve wouldn't. On the other hand, why waste energy (in heat) for such long hot pipes? It would make so much more sense to get a boiler near the shower tap (and use only a single cold water pipe to cover the whole distance - making the installation easier, cheaper, and saving energy due to the wasted heat). But I'd say that you could have _both_ working simultaneously... there might be some use cases for such an arrangement (e.g. having a _really huge_ boiler, powered by renewable energies, that provides hot water for a whole _building_, such as a hotel).

[@LOTPOR0402]

Do you really need a thermostatic valve on a shower being supplied from a combi boiler ? , or is this just for older systems

[@mikle65]

in my opinion it is just another thing that can brake and more expensive to replace. what is wrong with a manual mixer tap.

[@Teasuti]

​​​@@mikle65 nothing if your hot water is supplied by a boiler. But flow through gas heaters are more and more common and the temperatures can be all over the place with those. Especially with a restricted flow high pressure shower head. I find myself adjusting the mixer tap several times during a shower. Let alone when someone opens any other valve in the house.

[@elizabethj5294]

The explanation is great, the intro not so, especially "she has no idea how it works" - bit of an assumption there.

[@darude1420]

It's not a bad assumption really. Many people don't know how this works.

[@GwynethLlewelyn]

@@darude1420 I think that what @Elizabeth meant was that the video intro is showing a woman taking a shower, and the narrator assumes that because the actress is a _woman_ she does not know how a thermostatic valve works (while the male narrator/plumber/technician is _obviously_ an expert in the subject...). So the assumption isn't 'bad' or 'incorrect' by itself; it's just that, in the way the video has been produced, the language is a bit sexist (even if that wasn't intended). The intro could perfectly show a couple taking a shower (or a group of different people from different genders, all having a shower) and say 'they have no idea how it works' - that way, sexist language could be averted. It actually takes very little effort to _avoid_ sexist implications :-) I'm assuming that the intro is made of stock footage, and you can get stock footage for any gender really, it would be just as easy to edit the intro.

[@SuperAtruss]

So will the output volume vary when input pressures change? Is this not noticeable due to the large difference between supply and output pressure/volume for shower use? I can imagine if pressure drops on cold supply for some reason the hot supply would have to reduce in volume for safety thus potentially cutting off the shower. Can anyone speak from personal use and ownership?

[@allongur]

Yes. This is the "anti-scolding" feature of thermostatic mixing valves. If there is a large water pressure variation between hot and cold, the hot water flow will be restricted or cut off entirely to prevent scolding. Flow will resume when the pressures equalise.

[@LS-ot4ho]

C.H.E.E.S.Y presentation