Suitable NEW Shower system

[Alfapat]

I have installed a Samsung Outdoor Heat pump 16kw.

After 7 years , I have finally resolved and error which was down to the electrical wiring and central belt Scotland cowboys who went bust after one year , not helpful!

 

However , my bungalow is quite long and with the temperature of DHW in this system reaching normally 48degrees , the bath water has to run for some time like 2mns at least to be useful.

I am about to replace the electric shower to an up to date power one and with the system as it is , I am wandering if a Joules unvented tank for hot water and mains cold will be ok for a power shower with mixer . 

Is 48c hot enough and balance with cold mains. Mains is not high pressure , but the tank is probably fed with the same supply.

 

There is a thought that if I send the control unit(version 5 to the setting with three dots instead of eco two then there would be enough water , better than running a bath every night at least.

[Dave C]

I have an unvented cylinder heated via heat pump. Not Samsung or Joules, but the principle is the same... Setting the target cylinder temperature to 48c it works fine via a mixer shower (no pump in my case; mains pressure is plenty). Works fine when the tank has cooled a bit, too - I set the target temperature to 48c because then, even after 20 hours, it's still well over 40c and hot enough for a bath or shower, so I can just top up the hot water overnight on off peak rates.

 

Mixer showers do tend to say the incoming hot must be a certain temperature e.g. 50c+. Mine says that but thankfully it turns out that's rubbish. I suppose maybe it's possible some mixers actually do always mix in a fair amount of cold and in that case you really do need 50c+ hot supply; I guess my example just proves that mixers do exist where 42-48c hot supply works absolutely fine (but unfortunately you won't necessarily find it out by reading the shower instructions/specs...)

 

Maybe an expert can confirm whether all mixers are basically identical internally, and so they'd all work fine, or whether it's plausible that some will work fine and some not?

[Beelbeebub]

I think (and I may be wrong) there are mixers that are "scald safe". The idea is that if, for some reason, the cold supply only were to be interrupted the shower will shut down completely and there is no chance of some hot water getting through with no cold to mix down with.  The physical design to achieve this always lets some cold through so the min hot water temp is higher. 

 

Maybe that's the discrepancy? 

[ReedRichards]

I have a long bungalow so I installed a recirculation loop for the hot water (possible because the pipes are in the loft).  This costs money to run because the pipes circulating the hot water lose heat, no matter how well insulated.  But it gives you near-instant hot water out of any tap on the loop.

[Big Jimbo]

@ReedRichards I have often wondered if you could have fitted a PIR. Walk into the bathroom, and it kicks on the re-circulating pump. The instant hot water is a great idea, but having to have a pump running during awake hours, with the heat losses seems a shame.

[Big Jimbo]

@ReedRichards If you had run the pipes through the insulated envelope of the house, instead of the loss. Than the pipe heat loss, would have been a room heat gain. We could go on and on. I knew a strange chap many years ago. When you visited, and went for a pee, his bath would quite often be full of manky old water. When i asked him why he said he didn't drain the bath untill the water had gone stone cold. Refused to waste the heat. He had a good point.

[Big Jimbo]

He did look like Catweasel though, and his cups were filthy.

[Alfapat]

14 hours ago, Dave C said:

I have an unvented cylinder heated via heat pump. Not Samsung or Joules, but the principle is the same... Setting the target cylinder temperature to 48c it works fine via a mixer shower (no pump in my case; mains pressure is plenty). Works fine when the tank has cooled a bit, too - I set the target temperature to 48c because then, even after 20 hours, it's still well over 40c and hot enough for a bath or shower, so I can just top up the hot water overnight on off peak rates.

 

Mixer showers do tend to say the incoming hot must be a certain temperature e.g. 50c+. Mine says that but thankfully it turns out that's rubbish. I suppose maybe it's possible some mixers actually do always mix in a fair amount of cold and in that case you really do need 50c+ hot supply; I guess my example just proves that mixers do exist where 42-48c hot supply works absolutely fine (but unfortunately you won't necessarily find it out by reading the shower instructions/specs...)

 

Maybe an expert can confirm whether all mixers are basically identical internally, and so they'd all work fine, or whether it's plausible that some will work fine and some not?

So standing under a 50c temperature with a mixer shower from Air source heated  tank is hot enough, is it, can you tell me? Do you know the water pressure?

 

I may as I said further down this thread that if I can automate the booster heater to come in, this may compensate for temperature loss down to the end of the bungalow.

[Dave C]

11 minutes ago, Alfapat said:

So standing under a 50c temperature with a mixer shower from Air source heated  tank is hot enough, is it, can you tell me? Do you know the water pressure?

 

Yes, absolutely - ASHP is set to heat my tank to 48c, and the mixer shower is plenty hot enough even after the tank has had most of the day to cool a bit. Don't know the exact water pressure, just it's "very good" according to the plumber and I'd agree. As mentioned above, some mixers might not be happy with the incoming hot being 42-48c, but mine certainly is.

 

Feels unlikely you'd lose much temperature on your long pipe run if the pipes were insulated - just you've got the annoying long lead time to deal with.

[Alfapat]

Your correct about the long lead time , I get the reminder every night! I say to my partner just run the cold off first and dont rely on the hot water staying that hot with the lead time already in. However the pipes are insulated with some of it the old fashioned brown jute stuff, and this is Scotland .

 

Iam trying to up the temp with the cotroller with a higher flow , but seeing the code to set , other than that , three dots using the immersion may up the storage temp a bit more/

[TonyT]

Put a hot water return in, if you are getting grief about long delays for hot water?

[Beelbeebub]

Could you run a return in 15mm (or even 10mm) plastic back from the remote bathroom and have a hit water circulatory pump so you get instant hot water. 

 

If you slaved it to the light switch (or used a wireless switch on the wall -try quintec ones) then the pump would only run when you turned the light on. 

[Beelbeebub]

2 minutes ago, TonyT said:

Put a hot water return in, if you are getting grief about long delays for hot water?

Snap! 😁

[Alfapat]

 

On 15/08/2023 at 17:47, Beelbeebub said:

Snap!

On 15/08/2023 at 17:45, Beelbeebub said:

Could you run a return in 15mm (or even 10mm) plastic back from the remote bathroom and have a hit water circulatory pump so you get instant hot water. 

 

If you slaved it to the light switch (or used a wireless switch on the wall -try quintec ones) then the pump would only run when you turned the light on. 

Hmm , need more info on that one, if you had a pumped shower off the hot pipe surely the return would have to shut off as it would continually lose flow and pressure.

[joe90]

On 15/08/2023 at 09:22, Big Jimbo said:

he didn't drain the bath untill the water had gone stone cold.

I do the same 🤷‍♂️ why waste heat?

[Beelbeebub]

43 minutes ago, Alfapat said:

 

Hmm , need more info on that one, if you had a pumped shower off the hot pipe surely the return would have to shut off as it would continually lose flow and pressure.

depends where the return came off, if it came off after the pump then yes!

 

but you would usually put it returning just before the pump - which assumes the pump is very near the point of use eg under the bath.