ASHP and hot water cylinder.. struggle choosing the right shower! Help!

[finders]

Hi all, I've been reading through threads on similar topics on here and other forums, but still haven't been able to find an answer..

We have a very small new build and are looking to install a Vaillant Aerotherm plus 5kw and a 150L pre-plumbed cylinder, and the max hot water temp will be 50'c.

My understanding of thermostatic showers is that most have a min. temp inflow, which is normally 55'c, and often recommended to be 60-65'c. There is also a temperature differential, often of around 12'c, meaning that whatever the temp inflow is, the max possible outflow of the shower is going to be 12'c lower.

I have a few questions:

1. Do you have to follow the min temp inflow stated, or could I ignore it and have a 50'c inflow? If not, is anyone aware of showers with minimum temp inflows of 50'c or lower? I'm worried we might not always be at the 50'c mark even..
2. Are there showers with lower temperature differentials? (ie if it was 7'c, then I could still get 43'c with a 50'c inflow)
3. Biggest question: The best option is probably just to choose "manual mixer showers" - maybe I'm being really stupid, but I'm finding it incredibly difficult to find any shower sets that aren't either thermostatic or electric.. what am I doing wrong? I can find manual valves by themselves, but no shower sets.. 
   This is the sort of thing I'm looking for.. but with a manual mixer: 
   https://www.victorianplumbing.co.uk/mira-minimal-dual-outlet-thermostatic-mixer-shower-1-1943-002
   https://www.victorianplumbing.co.uk/hansgrohe-crometta-s-showerpipe-240-thermostatic-shower-mixer-27267000
   
   
   Thank you!!

 

Edited October 10, 2024 by finders

[Mike]

27 minutes ago, finders said:

is anyone aware of showers with minimum temp inflows of 50'c or lower?

Try Grohe - not the same as Hansgrohe. Their thermostatic mixers (at least the ones I've come across) require the hot water to be 2°C warmer than the mixed temperature. In other words, if you want a shower at 40°C, you need the hot water supply at the shower to be 42°C. I'm sure Ghrohe aren't unique in that.

 

BTW, Grohe's thermostatic showers have 'therm' in the name, to distinguish them from non-thermostatic. As in Grohetherm.

[ReedRichards]

I have seen post on this before.  Although many thermostatic showers say they have a minimum HW flow temperature that is too high for  a heat pump, actually most work perfectly well with lower temperature HW.

[nod]

1 hour ago, Mike said:

Try Grohe - not the same as Hansgrohe. Their thermostatic mixers (at least the ones I've come across) require the hot water to be 2°C warmer than the mixed temperature. In other words, if you want a shower at 40°C, you need the hot water supply at the shower to be 42°C. I'm sure Ghrohe aren't unique in that.

 

BTW, Grohe's thermostatic showers have 'therm' in the name, to distinguish them from non-thermostatic. As in Grohetherm.

+ 1 We’ve used Grohe again 

Seems to be fine with HP also

[marshian]

I have thermostatic mixer controls for both showers in the house - they are quite happy down to 40 deg supply temp on hot side.

 

They only get a little fussy when the HW temp is below 38 deg C

 

They are nothing special - both purchased on line (think soak for one and victoria plum for the other)

[SuperJohnG]

I've a Scudo throughout the house, valiant aerotherm 7kW ASHP,  we store at 52 degrees (baring in mind the tank thermostat is halfway up) works perfect. Don't stress buy what you need and you can always go up a little temp wise it's only a little off you COP. 

[Lofty718]

I have a boiler and PDHW setup and keep my UVC at 42c. Works very well

[finders]

5 hours ago, Mike said:

Try Grohe - not the same as Hansgrohe. Their thermostatic mixers (at least the ones I've come across) require the hot water to be 2°C warmer than the mixed temperature. In other words, if you want a shower at 40°C, you need the hot water supply at the shower to be 42°C. I'm sure Ghrohe aren't unique in that.

 

BTW, Grohe's thermostatic showers have 'therm' in the name, to distinguish them from non-thermostatic. As in Grohetherm.

Many thanks Mike, Nod and others. I had contacted Grohe before posting here, and they said that their thermostatic mixers require 60'C minimum inflow.. maybe I risk just ignoring that?

[Mike]

3 minutes ago, finders said:

they said that their thermostatic mixers require 60'C minimum inflow

Check their product datasheets - they say otherwise.

[finders]

3 hours ago, Mike said:

Check their product datasheets - they say otherwise.

Hi Mike - please can you direct me? Apologies if it sounds stupid, I'm literally looking everywhere.. I read through both the "Download Specification" and the "Technical Product Information" pdf files for multiple Grohe showers and I can't find anything about minimum temperature inflow - I have only found a piece that seems to suggest a minimum 2'c differential:

[Mike]

You've got it - that's what you're looking for: Hot water temperature at supply connection min. 2 °C higher than mixed water temperature :)

[finders]

Thank you!