Electric Shower Pressure Query

[Dave1UK]

Hi,

We are renting and have a electric shower downstairs (extension) - a 9.5kW Triton T80Z fast-fit electric shower as well as a combi boiler Viessmann Vitodens 100-W B1KC 35 kW. Upstairs is a standard shower/bath direct from boiler.

Our family members tend to use the downstairs electric shower and have been recently complaining about the water pressure. We are well aware that if any water outlet is being used in combination then there is a drop in pressure at both ends - for whatever reason. This has occurred at times when only the shower is being used though. I performed a approximate water pressure test using a 1L jug and a time of 6 seconds, results where when the electric shower heating element is essential off not operational i.e. cold then the pressure is 7.5L/min @ 0.75 bar. When at a reasonable temperature it is 6L/min @ 0.6 bar.

The electric shower is rated for 8L/min @ 1 bar. So I guess we are slight off?

The main query is whether there is anything that can be done to increase the water pressure, I read that due to having a combi boiler a water pump isn't possible, hence the electric shower route I'm assuming?

Also would an upgrade to the 10.5kW version with everything as is just a swap out make any difference as it's rated with a higher flow rate? I am aware that a new electric cable may need to be fed depending on the current setup however if there would be no improvement due to being bottle necked by the water pressure there wouldn't be a point.

Appreciate any help/advice.

 

[brianmoooore]

If both elements are working (which I think has been proven) and the water temperature is correct, and adjustable around that correct point, then the flow MUST be correct. Anything else would defy the laws of physics.
If the flow is correct, and you don't get an acceptable spray pattern, then a head has been fitted with too many holes, or holes that are too big.

 

[Dave1UK]

It’s an unusual, but wholly positive arrangement you have with your landlord.

We tend to get a lot of nightmare story’s on the forum of landlord that don’t give two hoots about tenant safety, and many of us jump to conclusions that the landlords in question are shirking doing the work.

I’m happy to learn otherwise here.


But I will advise not to blindly upsize the power of the shower without first checking the circuit is up to it… this includes the breaker, cable and isolator switch

Yeah if I was paying a high premium for rent like unfortunately some others then I sure would expect to be getting a top notch kitted property and landlord on speed dial to be honest. I think it's a fair trade off otherwise.

I wouldn't be upsizing, would be a like for like replacement, they still produce the same unit and model with same power rating. I previously mentioned on my post (quite bit of a read now) that I checked the power cables and fuse and they wouldn't be able to support a higher power rated unit unfortunately without an upgrade (the cabling would be quite a bit of work not worth it). Good advise though.

If both elements are working (which I think has been proven) and the water temperature is correct, and adjustable around that correct point, then the flow MUST be correct. Anything else would defy the laws of physics.
If the flow is correct, and you don't get an acceptable spray pattern, then a head has been fitted with too many holes, or holes that are too big.

Everything seemed fine to me when testing but then again I don't use it on a day to day basis, it is possible the heating elements may not work intermittently? Can't be 100% positive, in terms of the shower head it would be a good £20-30 for a branded replacement. A new unit complete set is around £240ish? £200 extra is a lot but it would rule out heating elements and either way we have all agreed to share the cost of it so it dampens the cost down even further.

Guess we will see.

 

[brianmoooore]

, it is possible the heating elements may not work intermittently? Can't be 100% positive, in terms of the shower heade.

The heating elements are switched by pressure switches inside the unit. These pressure switches are down wind of the flow controller, so can be affected by a head providing insufficient flow resistance (too many or too big holes), resulting in insufficient back pressure to work them reliably.
You can discount poor connections in any component affecting the element's power. Very high currents in a very small space will soon give themselves away by heat damage if there's any resistance where there shouldn't be.

 

[Dave1UK]

So went ahead and purchased a new unit few days ago, surprisingly wasn't as expensive as I initially saw online £120.46 delivered.

Got a chance to fit it yesterday and everything works as it should and after being used yesterday by a family member they said the pressure is much better and also temperature wise its stable.

The old unit was indeed correctly dated as 02/14, as the new one received is dated 06/23. So guess give/take few months.

Also the shower head on the old unit wasn't the original one, so it's possible that could have/played a part.

All in all, guess it worked out. A new shower head replacement may have been enough as advised by another member here however no harm in future proofing with having the whole unit replaced especially at that price point, age of unit etc.

 

[DPG]

So went ahead and purchased a new unit few days ago, surprisingly wasn't as expensive as I initially saw online £120.46 delivered.

Got a chance to fit it yesterday and everything works as it should and after being used yesterday by a family member they said the pressure is much better and also temperature wise its stable.

The old unit was indeed correctly dated as 02/14, as the new one received is dated 06/23. So guess give/take few months.

Also the shower head on the old unit wasn't the original one, so it's possible that could have/played a part.

All in all, guess it worked out. A new shower head replacement may have been enough as advised by another member here however no harm in future proofing with having the whole unit replaced especially at that price point, age of unit etc.

Thanks for letting us know. I think you made the right choice to be honest.