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Donato du plessis

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i am having trouble with my automatic pump flow control unit from mac afric.

How do i adjust the maximum presure or presure limit? It is curently running up to 7.5 bar and adjusting the screw at the top does not adjust the presure limit.image.jpgimage.jpg
 
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Donato du plessis said:
i am having trouble with my automatic pump flow control unit from mac afric.

How do i adjust the maximum presure or presure limit? It is curently running up to 7.5 bar and adjusting the screw at the top does not adjust the presure limit.View attachment 1763964View attachment 1763965
Click to expand...
Screw on top is usually only for delay ,pressure is not adjustable ,these things dont work like a compressor air switch ,some are current sensing so ie a 350 watt pump will give you 3 to 5 bar etc .that unit won't have any complicated internals ,screw the head and pump off and take it back ,don't take it apart .edit ,that's a 750 watt pump ,so 7.5 bar is spot on,ps you don't need higher than 4 bar in a home but the way pumps are specced aren't at all logical ,also a lot of pumps wont turn on if your geyser is high up as the head will prevent startup if only hot water is drained .
 
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It's hard to read but from what I can see that pump has an Hmax of 50m or 60m so 7.5 bar should not even be possible.

Anyways, the screw adjusts the starting/turn on pressure, not the final pressure. The standard adjustment range for these kinds of units seems to be 1.5-3 bar.

If you want full control of the start and stop pressure then you need something like this:

Pressure Switch 1-6Bar SK-2 – Water Pumps Online

waterpumpsonline.co.za waterpumpsonline.co.za

Then you'll also need a pressure tank to prevent fast cycling when the flow is low.
plumbitonline.co.za

PlumbIt

plumbitonline.co.za plumbitonline.co.za

This kind of setup also saves a lot of electricity compared to what you have now.
 
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Donato du plessis said:
i am having trouble with my automatic pump flow control unit from mac afric.

How do i adjust the maximum presure or presure limit? It is curently running up to 7.5 bar and adjusting the screw at the top does not adjust the presure limit.View attachment 1763964View attachment 1763965
Click to expand...
Per Soulie post, I have not discovered any change in pressure with these types of devices.

I use the smaller metabo 450w pump with the exact same automatic pump controller, as I found the bigger DAB 750w pump was too much pressure for me.


Pic of box, since I am not going outside now:
IMG_20241012_035242_845.jpg
 
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PS ,I hope you set the flow switch back to where it was ,if not correct ,under high flow conditions ie tap fully open to run a bath ,it will turn off every 10 seconds if it can't maintain the preset flow rate.
 
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soulie said:
PS ,I hope you set the flow switch back to where it was ,if not correct ,under high flow conditions ie tap fully open to run a bath ,it will turn off every 10 seconds if it can't maintain the preset flow rate.
Click to expand...

That screw doesn't adjust the flow rate, it adjusts the pressure differential. In the case of these units, this basically translates only to the "turn on" pressure.

In more detail; when you open a tap, the pressure drops. When it hits the set point (usually the screw allows an adjustment from 1.5-3 bar) then it turns on.

When you turn the tap off, the pressure rises again. When it hits the "turn off" pressure (also controlled by the screw, since the screw adjusts the differential) it signals the pump to turn off.

BUT with these units there is a ~10 second delay before the pump actually turns off. This delay is what causes the pressure to rise even further up to the pump's maximum pressure.

They put that delay in there to prevent fast on/off cycling of the pump when the flow rate is low.
 
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tetrasect said:
That screw doesn't adjust the flow rate, it adjusts the pressure differential. In the case of these units, this basically translates only to the "turn on" pressure.

In more detail; when you open a tap, the pressure drops. When it hits the set point (usually the screw allows an adjustment from 1.5-3 bar) then it turns on.

When you turn the tap off, the pressure rises again. When it hits the "turn off" pressure (also controlled by the screw, since the screw adjusts the differential) it signals the pump to turn off.

BUT with these units there is a ~10 second delay before the pump actually turns off. This delay is what causes the pressure to rise even further up to the pump's maximum pressure.

They put that delay in there to prevent fast on/off cycling of the pump when the flow rate is low.
Click to expand...
Yep, it's working as it should.
 
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tetrasect said:
That screw doesn't adjust the flow rate, it adjusts the pressure differential. In the case of these units, this basically translates only to the "turn on" pressure.

In more detail; when you open a tap, the pressure drops. When it hits the set point (usually the screw allows an adjustment from 1.5-3 bar) then it turns on.

When you turn the tap off, the pressure rises again. When it hits the "turn off" pressure (also controlled by the screw, since the screw adjusts the differential) it signals the pump to turn off.

BUT with these units there is a ~10 second delay before the pump actually turns off. This delay is what causes the pressure to rise even further up to the pump's maximum pressure.

They put that delay in there to prevent fast on/off cycling of the pump when the flow rate is low.
Click to expand...
I know exactly how they work ,I install and service them. You have a lower limit which when at the lower position allows the pump to turn on ,the upper limit turns it off ,if at the lower limit and there isn't enough flow to lift the diaphragm it will cut the motor after 10 seconds .how many have you installed and serviced or is it just Google talking ,and that is why they are sold as flow switches and not pressure switches .
 
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soulie said:
I know exactly how they work ,I install and service them. You have a lower limit which when at the lower position allows the pump to turn on ,the upper limit turns it off ,if at the lower limit and there isn't enough flow to lift the diaphragm it will cut the motor after 10 seconds .how many have you installed and serviced or is it just Google talking ,and that is why they are sold as flow switches and not pressure switches .
Click to expand...
Why are you being so touchy?

What you said here is not correct:
soulie said:
set the flow switch back to where it was ,if not correct ,under high flow conditions ie tap fully open to run a bath ,it will turn off every 10 seconds if it can't maintain the preset flow rate.
Click to expand...

All I did was explain in a little more detail what the screw does and that the screw does not influence the flow rate. Also, cycling happens at a low flow rate, not a high flow rate.

Additionally, in your first post you said the screw adjusts the delay time. That was incorrect as well.

So excuse me for correcting you, "switch master", but I really don't care how many of these you've installed.
I simply responded to what you wrote here.
 
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rh1 said:
Have you have any experience with the shop or the product?

Longevity?

At a R1000, its about double the price of the mac flow switch, but if it can set the pressure, it could be what OP needs.
Click to expand...

Haven't used one, but I'm thinking of getting a DPR to see how it fares compared to my mechanical switch + pressure tank setup.

They look pretty awesome.

Spanish company as well, so quality should be good.

Shop looks legit, they are on google maps and have a facebook page, instagram etc.
 
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