Saving energy with a Triton T90 Shower?

TPM · 16-03-2012 01:15AM

unlike the t90si, i cant see the t90xr being around in 10-12 years, the internal components look alot cheaper imo

Coles · 16-03-2012 01:59AM

Billy Bunting wrote: »

IMO, they are all lacking when it comes to the OP's design, although the thermal cut out will safe gaurd any disaster. I would sugest that the first test on your unit would be to run it without the heat setting with your 35o run ning through it to see just how the pump impellor housing and bits cope with the temperature that they defo weren't intended for.

I don't accept that they weren't designed to be able to take a reasonably high temperature cold water supply, but you're right, -if there is going to be a problem that's where it'll be. I have been looking at the process of how the supply water gets into the heater can and there is the potential for difficulties.

Certainly within the heater can there won't be any problem.

deandean · 16-03-2012 03:37AM

Ach coles now ya have me thinking about this in my sleep! So set the system up. Start with your TMV at 15degC and run tests. Then increase TMV in 5deg increments, testing with a good run each time. Be conservative, i.e. if it is working Ok at 40deg, turn the mixer back to 35deg and lock er at that.
Please do post your findings, most interezting!

Coles · 16-03-2012 08:56AM

deandean wrote: »

Ach coles now ya have me thinking about this in my sleep! So set the system up. Start with your TMV at 15degC and run tests. Then increase TMV in 5deg increments, testing with a good run each time. Be conservative, i.e. if it is working Ok at 40deg, turn the mixer back to 35deg and lock er at that.
Please do post your findings, most interezting!

Thanks deandean. Unfortunately it won't be possible to test the idea in that way because of the limitations of the TMVs. Most of the domestic ones seem to be able to output a blended flow in range of temperatures, but usually that range starts at 32C and increases in increments towards 40+. That's perfect for a supply for the 'Low' setting on the T90 where the small element is using 2.1kW to raise the flow by 7C.

As a side note it would also be possible to use the 'Medium' setting on the Power Selector to make use of the 5kW(?) element. The blended supply would need around 20C so obviously there would be less concerns about the supply water temperature. Of course the benefits would be also greatly reduced and it would probably not be worth doing.

So what needs to be figured out?

- Can the T90 handle a supply of 32C,

- What TMV is most suitable. What else is required. How much will it cost.

and...

- What is the real benefit.

Joey the lips · 16-03-2012 09:05AM

Just a couple of small points to consider.

The hot water needs to get to the pumped electric shower. If its pumped it will have to be reduced to a very low pressure.

You cannot have the hot water overflow into the cold tank. Obvious reasons on this one.

Coles · 16-03-2012 09:59AM

Joey the lips wrote: »

Just a couple of small points to consider.

The hot water needs to get to the pumped electric shower. If its pumped it will have to be reduced to a very low pressure.

You cannot have the hot water overflow into the cold tank. Obvious reasons on this one.

That does raise an issue. With a 1/2" supply and a flow rate of 4.5ltrs/minute it would take about 7 seconds for the warm water to travel the 5m to get from the cylinder to the shower. The instant shower would not be very instant. Not a major problem, but just something else to consider.

With regards to the hot water overflowing to the cold tank I'm not seeing a major problem here, certainly not a problem that doesn't already exist with any hot water cylinder. Perhaps I'm missing something.

Joey the lips · 16-03-2012 10:40AM

Coles wrote: »

That does raise an issue. With a 1/2" supply and a flow rate of 4.5ltrs/minute it would take about 7 seconds for the warm water to travel the 5m to get from the cylinder to the shower. The instant shower would not be very instant. Not a major problem, but just something else to consider.

With regards to the hot water overflowing to the cold tank I'm not seeing a major problem here, certainly not a problem that doesn't already exist with any hot water cylinder. Perhaps I'm missing something.

The 7 second constant unfor would be enough to starve the shower of water so this will have to be overcome or the shower will trip or burn out.

There is 2 issues with the water overflowing into the tank in the attic.
1. It will fill up and flow out the overflow pipe.
2. If the temperature increases in the cold water tank in the attic it will become a breading ground for bacteria

However if in principle the 7 second issue can be resolved then the water can be prevented flowing into the tank with non return valve.

Coles · 16-03-2012 04:17PM

Joey the lips wrote: »

The 7 second constant unfor would be enough to starve the shower of water so this will have to be overcome or the shower will trip or burn out.

Sorry Joey, I think I caused a bit of confusion when I said 'the instant shower would not be very instant'. What I meant is that it wouldn't reach it's correct temperature until the water from the hot water cylinder reached it. Of course there will always be a supply of water to the shower unit.

The only problem with the delay in getting the warm water from the cylinder to the T90 is that it will run unpleasantly cool for 7 seconds. When the shower is turned on it is likely to be set to it's new 'preferred' setting, - 'Low' power (the 2.1kw heating element), and a flow rate of 4.5 litres per second (between 4 and 5 on the flow/temperature control knob). The water flowing into the T90 initially will be at around 20C (ambient temperature around the pipework) and the T90 will warm it by 7C to a slightly unpleasant 27C. As soon as the warm blended flow from the TMV reaches the T90 the shower temperature should increase to a pleasant 39C. No smoke or sparks!

With regards to the second part of your post, I'll throw together a sketch to show how I think it might work and we'll see if we can figure out where the problems might be (and any additional measures that are required to overcome them).

Coles · 17-03-2012 12:05AM

Here's a sketch which hopefully will clarify the proposal a bit.

The temperatures in the header tank and cylinder are just indicative. Obviously they'll fluctuate on a daily basis.

Coles · 20-03-2012 10:55PM

No need for non-return valves?

maradonas · 20-03-2012 11:18PM

most people put in the t90 and a mixed shower side by side. it looks amazing with exposed chrome piping!!

JohnnieK · 22-03-2012 12:21AM

Any more movement on this Coles?

Coles · 22-03-2012 12:28AM

JohnnieK wrote: »

Any more movement on this Coles?

No not really. I measured the available pressure of my set up at 0.17 bar so I'm spending time looking for a TMV that will work at such a low pressure. I think a normal 'low pressure' TMV will work regardless even though it's a bit below the recommended range.

I'm convinced the system will work and I don't see any problem with the warm water supply to the T90.

Deesse · 02-10-2025 01:18AM

Hi Coles. I've been thinking of trying the exact same thing, as I've a tank of hot water occasionally that I'd prefer to use rather than heating from cold.

I stumbled upon your post, in which you give the only well-reasoned analysis I can find, so may I ask if you ever progressed the experiment?

Thanks in advance.

02-10-2025 09:22AM

All electric showers must be BEAB certified. This means that they are fully tested & all safety features work. All electric showers have a maximum inlet water temperature. If you exceed the inlet temperature then that shower may be dangerous to you because you are using outside it's designed perimeter. This voids any warranty on the shower parts. It also leaves you liable if anyone got scalded because you modified the installation. There are strict installation instructions with all electric showers. All electric showers have to have their own dedicated supply directly from the cold water tank.

If you insisted on doing it then you would need to know the maximum inlet water temperature for the shower to run safely. Triton Tech support will tell you this. You then need to be 100 percent certain that the inlet temperature can't exceed this temperature. This involves creating a setup where if the water temperature exceeds the maximum allowed for the shower that the shower won't work.

It's a crazy idea imo & can be extremely dangerous. At the end of the day, after taking all the risks you are only going to save pennies.

blackbox · 02-10-2025 11:55AM

Triton specify a max inlet temperature of 28 deg C.

I can't imagine that the sky will fall if it went a few degrees above this.

My main problem with these showers is the need to reduce the flow in winter when the attic tank is very cold.

John.G · 02-10-2025 01:38PM

Yes, 28C is the max inlet, I have seen one running too hot last summer with a (natural) cistern outlet temp of 23C, the TCO, (thermal cut out) operates at 48C. A neighbours T90SR gives a maximum flowrate of 10.0LPM but it would be very prudent to use say 7.5LPM to give a bit of leeway, at this flowrate the dT through a 9.0kW shower will be 17.2C, a minimum showering temp of 35C then means a max "safe" cistern temp of 18C, this will still give a flowrate of 5.86LPM at 40C, still a lot better than the 3.91LPM from mains of 7C in the very debths of winter, obviously, can't recommend this and TRITON certainly dont, they clearly state Cold water storage ONLY.

02-10-2025 02:33PM

Shower won't work correctly if the

https://www.boards.ie/discussion/comment/123869903#Comment_123869903

Threads suggesting modifying electric showers usually get shut down or deleted because of how dangerous it can be. I'm not sure how this thread is still going tbh

There is a maximum temperature for a reason. If you exceed this the shower can't function correctly & it's likely someone could be scalded. The safety features that all electric showers must have fitting under EU safety law might not work.

I can't stress this enough, if you go against the installation instructions it voids everything. Triton are no longer responsible for the shower. If someone does get scalded or electrocuted you are legally responsible for their injuries.

The only way to do this safely is to run a hot & cold feed into a thermostatic mixer and set the maximum temperature to the maximum stated by Triton. Even this can be dangerous because there is no safety feature between the thermostatic valve and the shower. If the valve fails in any way then someone having a shower can be scalded

Again I would point out that you are looking at saving pennies. Remembering there is a risk of a prison sentence for you if someone is electrocuted due to you making an electric shower so unsafe.

I highly recommend you don't attempt this. For what it's worth I'm around 35 years in the shower repair business

Saving energy with a Triton T90 Shower?

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