GHL Profilux Standalone Doser

[Canadian]

How approximate are we talking when the instructions say "approx. 60 mL/minute" ?

I just went through the process of calibrating my new doser and pump 1 doses 43 mL/minute and pump 2 doses 50 mL/minute.

Do these values fall in line with the typical deviations/tolerances normally seen in a GHL Profilux standalone doser?

[Canadian]

I just discovered that the flow rate varies considerably depending upon how long the tubing is on the intake side. The values I reported above were with the intake tubing at 22" and when I re-calibrated pump 1 with 13" of tubing on the intake it was 47mL/minute.

I guess I'll just have to set up each pump in place with the tubing laid out the way it will be once everything is operating and then re-calibrate. I know the instructions say the "tube on the intake side should be short", but is there a length that is considered too long or potentially too stressful for the pump to draw the fluid up?

[Aqua-Digital]

we have tested them to 50'.

So as you have said, set up your dosing tube run and then calibrate

4.3 Calibrate
Our pumps have an average flow rate of approx. 60 ml/minute. If a pump has a deviation caused by tolerances this can be
entered in the menu Calibration. First you have to select the pump, and then you can enter the Flow rate of this pump.
In order to find out the actual flow rate do this: Activate the pump manually for exactly one minute and measure the amount
which has been pumped during this time.
Hint: The set flow rate does NOT change the actual performance of the pump (it will always run with the same speed)!
The set flow rate is used by the controller to calculate the on-time based on the desired dosing amount.

[Canadian]

Michael,

When you tested it at 50' did it also have any significant vertical length it had to pump up? Right now I have mine set up to pump about 3' vertically and I'm finding that the three rollers aren't keeping the column of fluid steady leading to some of the fluid flowing back into the dosing containers and causing erroneous dosing volumes (because the pumps aren't keeping the fluid at the end of the dosing lines).

Should the pump/three rollers be able to keep the fluid constant in the tubes? I know my old AquaMedic only had two rollers and therefore required check valves to be installed to avoid this same problem. I was hoping this unit would not require this.

[Aqua-Digital]

You will need a check valve this is standard with any doser as the wheels do not act as an air tight seal.

[Canadian]

I didn't realize this unit required check valves. There's no mention of it in the instructions. And there's no mention of where they should be installed (before or after the pump - on my AquaMedic they are installed both before and after the pump). But I wasn't sure if 3 rollers was enough to negate the use of a check valve as the Liter Meter III has 4 rollers and does not require check valves.

Does GHL Profilux sell check valves or is there a brand they recommend?