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Heat loss, and the result


Big Jimbo

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10 hours ago, Big Jimbo said:

So with 4 showers, i am going to be looking for a peak demand of 40L per min. Oh, for a decent water engineer. Going to reach out to another One today.

 

I would humbly suggest that you employ a water engineer that sits you down to have a proper think about the real world water demands and whether all the outlets are actually going to be used at once 😉 I know it's not what many want to hear on BH but the reality is that when you sit down to work out the real patterns in a house the concurrent demands are less than most people think. You've also got the pesky building regs and resultant design guidelines suggesting less water use per person.

 

I know I've said this before but when I designed my system I started off in the same trap. I thought I needed to supply 3 bathrooms concurrently blah blah.However, instead of looking at upgrading the mains supply and accumulator, hot water recirculation and so forth, I looked instead and reducing overall flow rates while retaining pressure so even with less than 30l/min peak flow I can supply all bathrooms and whatever outlets without anyone complaining - although my only complaint is that I feel the kitchen tap (which comes restricted to 6l/min as standard) doesn't fill my pots quite quickly enough when I'm in a hurry. Our current main drench shower is regulated to 6l/min and it works really well. This approach was in part inspired by comments made by @markocosic to a thread I started a while ago about a similar question. Just fundamentally changed how I looked at the problem.

 

You can also use 10mm pipe for toilets, basins, dishwasher, washing machine which also reduces impact on flow.

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@SimonD I started in the same place - wife demanding, we be able to run 3 showers at once, because it would be required.  The system I installed could just do that. Only time 3 showers have run at once is when I did the test. Since then only one shower at time, used, irrespective of how many people are in the house. 

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1 minute ago, JohnMo said:

@SimonD I started in the same place - wife demanding, we be able to run 3 showers at once, because it would be required.  The system I installed could just do that. Only time 3 showers have run at once is when I did the test. Since then only one shower at time, used, irrespective of how many people are in the house. 

 

7 minutes ago, SimonD said:

 

I would humbly suggest that you employ a water engineer that sits you down to have a proper think about the real world water demands and whether all the outlets are actually going to be used at once 😉 I know it's not what many want to hear on BH but the reality is that when you sit down to work out the real patterns in a house the concurrent demands are less than most people think. You've also got the pesky building regs and resultant design guidelines suggesting less water use per person.

 

I know I've said this before but when I designed my system I started off in the same trap. I thought I needed to supply 3 bathrooms concurrently blah blah.However, instead of looking at upgrading the mains supply and accumulator, hot water recirculation and so forth, I looked instead and reducing overall flow rates while retaining pressure so even with less than 30l/min peak flow I can supply all bathrooms and whatever outlets without anyone complaining - although my only complaint is that I feel the kitchen tap (which comes restricted to 6l/min as standard) doesn't fill my pots quite quickly enough when I'm in a hurry. Our current main drench shower is regulated to 6l/min and it works really well. This approach was in part inspired by comments made by @markocosic to a thread I started a while ago about a similar question. Just fundamentally changed how I looked at the problem.

 

You can also use 10mm pipe for toilets, basins, dishwasher, washing machine which also reduces impact on flow.

The biggest problem I encounter with self builders is either too much micromanagement of stuff that is really insignificant, or just a complete lack of investment in the most basic of forethought and M&E planning.  Seems one or the other tbh.

The micromanagers seem to lose sleep overthinking  / over engineering / worrying about stuff which has never caused them issue; up to them making the new home! 

I would install a medium sized accumulator without a seconds hesitation, as the uplift in the performance of the entire hot and cold system is remarkable. No dip in pressure and flow when a loo is flushed when a showers running etc, just night and day difference tbh for not much money. 

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3 minutes ago, Nickfromwales said:

I would install a medium sized accumulator without a seconds hesitation,

We have a borehole and have the very thing upstream of the filter system.  

 

4 minutes ago, Nickfromwales said:

No dip in pressure and flow when a loo is flushed when a showers running etc, just night and day difference tbh for not much money. 

Couldn't agree more

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11 hours ago, SteamyTea said:

@Nickfromwales, @JohnMo

Are accumulators basically maintenance free, maybe not quite fit and forget, but close to it?

The bladders do wear out eventually, but are changeable in the decent units. TBH I have these in customers homes that I’ve installed over 15 years ago and they still have my mobile number, as do all my previous clients, so if there was a failure I can only assume they would be on the phone for support (as some had such bad pressure / flow that if the kitchen tap was running downstairs and you opened the basin tap upstairs, you’d hear air being sucked into the tap and zero water would come out). 
I demonstrate the accumulators to the clients by opening every tap in the house, simultaneously, and they just cannot believe it. Then I show then that the cold mains is isolated and then open that and it gets better again! 

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On 16/09/2023 at 08:13, Nickfromwales said:

The bladders do wear out eventually, but are changeable in the decent units. TBH I have these in customers homes that I’ve installed over 15 years ago and they still have my mobile number, as do all my previous clients, so if there was a failure I can only assume they would be on the phone for support (as some had such bad pressure / flow that if the kitchen tap was running downstairs and you opened the basin tap upstairs, you’d hear air being sucked into the tap and zero water would come out). 
I demonstrate the accumulators to the clients by opening every tap in the house, simultaneously, and they just cannot believe it. Then I show then that the cold mains is isolated and then open that and it gets better again! 

 

recommend any particular brand or make ?

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On 15/09/2023 at 20:13, Nickfromwales said:

I would install a medium sized accumulator without a seconds hesitation, as the uplift in the performance of the entire hot and cold system is remarkable. No dip in pressure and flow when a loo is flushed when a showers running etc, just night and day difference tbh for not much money. 

I decided against one to start with as our toilets are flushed from the RWH tank so that shouldn’t affect showers etc. 

 

I guess if I find we have pressure issues we can fit one at a later date. 

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11 hours ago, Dave Jones said:

 

does it not need a pump ?

Nope!

 

5 hours ago, SteamyTea said:

P/V=C

My sincere apologies. The house was burgled last night and the only thing the bastards took was my beloved scientific calculator. "What are the odds?", I said..... Given current market value I have set the reward for its immediate and safe return at £8.99 (or £6.99 if you have a Tesco Clubcard).

 

These take the network pressure and 'lend' it to you, for the grand sum of FOC. Peak times for you to harvest said free energy are around 3-4AM plus some sporadic pockets during the daytime, and the name for this is "stored energy", the fact you borrow it each day is what makes this a great solution.

No pumps, no maintenance (other than annual check of pre-charge pressure and occasional top up), and no electrical / other consumption seen by you, the user. Happy days.

 

A survey of your max peak pressure per 24hrs is essential, achieved by connecting a pressure gauge with a double-check NRV on it to capture the peak reading, so you can correctly size the vessel and set the correct pre-charge pressure (so it actually fills with water). 

 

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20 hours ago, SteamyTea said:

Will be at atmospheric pressure when it leaves the shower head.

Well sure, but the feel of 6l/min coming out of a shower head at 3-4 bar is going to be different to the feel at 1-1.5 bar.

 

I'm having a job putting "drench" and "6l/min" together in the same sentence so keen to hear more as I'd like to cut our water usage.

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