Terrible water heating rate on T90si Shower

ruicosta10

Curious as to what sort of performance people get from this shower... My attic tank is a very large one, I think at least 60 gallons, but I have seen older Triton electric showers running off much smaller attic tanks which have a much better flow to water heat rate.

Its improving now as we head into the warmer months of the year... but in winter you literally can't shower in it, and have to bugger off downstairs and hope there's enough hot water to use the mixer shower. I know electric showers are not ideal in the invigoration stakes... but my one is a joke.

Mr Magnolia

Something wrong here my friend. Your heating element may be goosed or your tank may not be suitable

To ensure correct operation of the shower, it must be connected to a gravity fed cold water storage cistern, mith a maximum head of water of 10 metres and a minimum head of water of 0.08 metres, as measured between the bottom of the storage cistern and the top of the unit.

From here

Aside/ We never use electric shower in our house, the power from the pump shower fed from the hot tank is superb so we use this

Reyman

As I understand it the flow rate from those electric showers is largely dependent on the temperature of the water entering the shower from the tank /cold water circuit.

There's only 8-9KW of heating power available tothe shower and it automatically adjusts the flow rate to heat the water to around 40C. If the entering water is cooler the flow rate is reduced to allow the water to be heated to the required temperature

GreeBo

is you cold water tank lagged?

TKK

What would be the most suitable product/way to lag a cold water tank? I really have to get around to it.

Mr Magnolia

AFAIK, it needs to remain un-lagged on the underside/bottom. This is to allow heat from the house to keep the water from freezing, this could cause damage to the tank and pipework. You could use glas wool to insulate, just make sure you don't get any in the water

byte

Curiously, my T90si seems to have similar issues. During the winter, I'd need to turn the control up to 10, and sometimes even then it's not hot enough.

Now, this time of year, having the control at 5-6 is sufficient.

I had also been thinking that the tank needs to be lagged to prevent the water going too cold.

311

I always wondered why lagging the tank was now a regulation ,considering the amount of energy you need to heat water ,lagging saves you using electricity to do this

Stoner

Sparks400 wrote:

AFAIK, it needs to remain un-lagged on the underside/bottom. This is to allow heat from the house to keep the water from freezing, this could cause damage to the tank and pipework. You could use glas wool to insulate, just make sure you don't get any in the water

Yeah I agree with this, it's fairly common to see underneath a tank insulated, this can cause a few degrees of temp difference.
If its the case just pull the insultaion out from under the tank. It also sounds like there is another issue though either with the tank being too close to the shower as discussed above.

Reyman

Lagging the tank won't solve your shower temperature problem. Those electric showers just don't work in the winter.
You would need around 13KW to get a good flow and hot water and this isn't possible because your mains supply is max 63Amps so all the total electrical capacity of the house would be used by the shower.

Put in an ordinary Mira off the Immersion in the hot water cylinder and make sure you've at least a 4' head to the shower outlet from the attic tank.

You'll be ok then!

TKK

I almost forgot about this one. I have one of those showers too and it was having trouble (it was mainly going from hot to cold & back to hot while running). I opened it up and discovered a layer of dirt on the temperature sensor which, since cleaning it, has resulted in the temperature being maintained and I was able to turn the temperature dial down resulting in a better flow rate.

Mr Magnolia

TKK wrote:

I almost forgot about this one. I have one of those showers too and it was having trouble (it was mainly going from hot to cold & back to hot while running). I opened it up and discovered a layer of dirt on the temperature sensor which, since cleaning it, has resulted in the temperature being maintained and I was able to turn the temperature dial down resulting in a better flow rate.

Must remember that one

lescol

Hi Ruicosta,

Have been using a T90si 9.5kw for 3 years. In the coldest days of winter the temp dial is possibly up to 6, currently 4, in mid summer have to turn the power selector to one red bar as it's impossible to get it running cool enough!

FrinkDink

lescol wrote:

Hi Ruicosta,

Have been using a T90si 9.5kw for 3 years. In the coldest days of winter the temp dial is possibly up to 6, currently 4, in mid summer have to turn the power selector to one red bar as it's impossible to get it running cool enough!

Yeah, in mid summer I can get it down to about 2 on the warmest days.... it's a shame we were colonised by the Brits and took their crappy plumbing and water storage techniques. Just about every European country I've been to, as well as the States have high pressure, and unlimited hot water storage, it'd make you envious when you're shivering away in an electric shower in mid winter!