shower heater liters per min water flow questions

[Artisi]

15 minutes ago, sometimewoodworker said:

I am not ignoring that, it is the output available from a ½” outlet

 

The available flow with a ¾” outlet is virtually double.

Are you saying the 1/2" outlet is limiting the flow to 19 litre / minute? 

[sometimewoodworker]

2 hours ago, Artisi said:

Correct, without having the necessary info such as to height to the outlet (static head), length of pipe run, pipe diameter, how many bends / T junctions etc  its a bit like crystal ball gazing - however working backwards that is always hit-and-miss and without knowing how accurate the bucket flow measurement is, 19 lpm equals 1.14 m3h --- from the 50hz pump performance curve it indicates the discharge head is over 40 m head at the pump --- now that's a lot of static head and friction loss. 

Of course is the pump running at full speed, no blockages in the discharge or inlet pipe and the water supply can meet what is required. 

You are disregarding the data.

½” outlet with a 3.5bar setting gives 19 litres per minute 

¾” outlet with a 3.5bar setting gives 38 litres per minute (though the pipe run is virtually 3 times longer)

 

it is the outlet size that is restricting the flow not the pipe bends, T junctions, friction losses, static head etc.

 

so in this particular case none of the information you are looking for is irrelevant.

 

the relevant information that you and and sandyf are ignoring is that in the original post

 

On 1/3/2022 at 10:31 AM, flipper2222222 said:

With heater connected cold water
8 liters 
With heater connected hot water
8 liters 
With no heater connected but with hand shower
16 liters
Tap only
19 liters

1) He wants more litres per minute 

2) His tap can supply more than double the flow from his (mine and probably most other instant water heaters)

3) His shower head cope with twice the flow his water heater will allow 

 

So why F*F*S* will any more data change anything or be in any way relevant in this case???

 

It will not change the fact that he has adequate supply for 2 heaters.

It will not change the fact that he has an adequate shower head for 2 heaters.

It will not change the fact that he has a standard heater that can only supply ½ the flow his shower head can deal with

 

If you are designing large water supply systems then yes all of that data is needed for the correct pump to be installed, but it isn’t needed in this case. I have no doubt that were the situation different then the data could be useful in determining a solution.

 

 

[sometimewoodworker]

13 minutes ago, Artisi said:

Are you saying the 1/2" outlet is limiting the flow to 19 litre / minute? 

Yes 

same pump.

same setting in bar (3.5)

 

½” outlet 19 L/M

¾ outlet 38 L/M

Edited January 17, 2022 by sometimewoodworker

[sometimewoodworker]

22 minutes ago, Artisi said:

Are you saying the 1/2" outlet is limiting the flow to 19 litre / minute? 

I don’t know Flipper’s supply pipe size mine is PP-R 32mm with a reduction at the outlet. So I don’t know if he will get a higher L/M  with a larger tap. But it isn’t important as the instant heater is limited to 8 L/M

My shower is virtually the same flow.

 

What do you get? I’ve shown you mine please show me yours ???????? 

 

 

Edited January 17, 2022 by sometimewoodworker

[sometimewoodworker]

5 hours ago, sandyf said:

What did you find difficult about the words "not familiar"

I have been here a long time and it looks like Mitsu and Hitachi are the most widely used.

I understood your lack of familiarity with his pump. I too was unfamiliar with it until I researched and bought one. I also know that Mitsubishi and Hitachi pumps are the most common and that they have a cutoff pressure that maxes out at 2.8 bar for the vast majority with the Mitsubishi inverter going to 3 bar. I posted the information about our SCALA2 pumps precisely because they are extremely unusual for a domestic pump with the possibility of producing twice the pressure of most others.
 

It was for this exact reason I posted the page from the instruction manual, as the information is then defined for all to see and not just an imaginary number. My post was never designed to imply anything other than the words it contained.  

[flipper2222222]

hi guys.

 

I am happy with the 19 litres per minute flow at the tap. I am considering splitting the flow between 2 t-pieces, I did post the below a while ago, might have missed or misundertood if it has been answered in subsequent posts, so posting it again below.

 

my latest thoughts was to take the suggestion from sometime wood worker of adding a second heater. but prior to doing this (for testing purposes and maybe be able to save the cost of s second heater)  add 2 t-pieces (in total) one at the tap end and other at the shower head end

one line direct to the shower head (8 litres per min approx. ) and the other via the heater (8 litres per min approx.) a total of 16 litres per min 

I would expect to lose 50% heat but would the direct water side not going to heater push through too much water and not let as much as the warm water from the heater thereby making the heat loss much more than 50%?

thanks for all the contributions 

 

 

[sometimewoodworker]

38 minutes ago, flipper2222222 said:

hi guys.

 

I am happy with the 19 litres per minute flow at the tap. I am considering splitting the flow between 2 t-pieces, I did post the below a while ago, might have missed or misundertood if it has been answered in subsequent posts, so posting it again below.

 

my latest thoughts was to take the suggestion from sometime wood worker of adding a second heater. but prior to doing this (for testing purposes and maybe be able to save the cost of s second heater)  add 2 t-pieces (in total) one at the tap end and other at the shower head end

one line direct to the shower head (8 litres per min approx. ) and the other via the heater (8 litres per min approx.) a total of 16 litres per min 

I would expect to lose 50% heat but would the direct water side not going to heater push through too much water and not let as much as the warm water from the heater thereby making the heat loss much more than 50%?

thanks for all the contributions 

 

 

I would suggest that you arrange your test plumbing setup so that adding a second heater is a simple job. I also suggest that you install one of the shutoff/flow control valves on the cold side bypass.  These are available everywhere with 1 or 2 controlled outlets and are usually used on toilet supplies.

 

 

[flipper2222222]

On 1/20/2022 at 3:41 PM, sometimewoodworker said:

I would suggest that you arrange your test plumbing setup so that adding a second heater is a simple job. I also suggest that you install one of the shutoff/flow control valves on the cold side bypass.  These are available everywhere with 1 or 2 controlled outlets and are usually used on toilet supplies.

 

 

On 1/20/2022 at 3:41 PM, sometimewoodworker said:

 

Finally got back and got to test the dual hose setup, the pressure is good enough for me to be happy with. don't need another inline heater.

 

thanks to  sometimewoodworker for your help, patience and advice.