quote:

Originally posted by rusty:
es, I have two .pdf's that will make your life easy: A description of each of the 4 pins and what each needs to see in order to control the pump speed. I can email them to you. Cliff notes:

Pin 1 is battery voltage
Pin 2 is PWM signal
Pin 3 is a test/BSD signal
Pin 4 is Ground

Supplying +12volts to Pin 1 AND pin 2 (and grounding pin 4) should make it run full speed after a 'timeout' period of about 3-10 seconds. To vary speed based on PWM input on Pin 2, you need at least 3ms of an inturrupted high pulse in order for it to awake the pump. Keep that in mind when you decide on the PWM frequency and/or your duty cycle percents.

PM me your email address or email me at timmafod at gmail.
bruce leave #3 ungrouded and power to 1 and 2

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I tested one of the knockoff pumps, too.

With the same results. It would not really work ... And I tried everything.

I don't think they have the same interface as the genuine Pierburg ones, or their control circuitry is so inferior that it is unable to be self aware of the shaft speed.

I remember a warning from Pierburg that those copies are not able to deliver the same flow at a given pressure.
So yes those things seams to be a bit weaker than the genuine ones.

We are using one on a Time Attack car (SR20) and it is not even using its full current capability's.

The original CWA200 with the most compact mounting points is the "11517586925", there is also a "11517586929".

The currently "normal" aftermarket CWA400 version is the BMW number "11517604027".

11517586925: https://www.turnermotorsport.c...4-30-n51-n52-engine/

11517604027: https://www.turnermotorsport.c...-f10-x1-f25-f26-e89/

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Centrifugal pumps are designed to pump liquids not gases. Any centrifugal pump (even a self-priming pump) will not start pumping unless at least the first stage (such as in a multistage vertical pump) is full of liquid. When pumping a liquid with an excessive amount of entrained air, the air/gas tends to be centrifuged inward towards the eye of the impeller, eventually blocking any liquid flow through the pump (air binding it). If this only happens occasionally, the pump has a positive suction pressure (flooded suction), and the flow stoppage can be quickly detected, stopping and restarting the pump can clear up the air binding.

quote:

L/FM fire pumps require what is commonly called a “flooded suction,” or a positive suction pressure prior to starting. The concept is that the water supply source must arrive at the pump impeller on its own, without the aid of the pump. This will guarantee that the pump is properly primed and ready for operation. With many centrifugal pumps, as little as 3% air in the casing can be enough to prevent the proper operation of the pump. So it is important to maintain a positive pressure on the pump prior to starting.

But even a pump with a proper suction supply can have air in it, or not be fully primed. We are often asked about how to prime pumps when first installed, or how to prime pumps that are used with a water level source below the elevation level of the pump (not flooded suction).

Unless you have a self-priming centrifugal pump (liquid primed, compressed air primed, or vacuum primed), you will need to manually prime it anytime it might become filled with air or gases. Priming a centrifugal pump is essential if you want it to function properly, otherwise the suction pressure created will not be sufficient enough to lift water, and this can cause issues such as overheating and pump failure. Unfortunately this isn’t too uncommon since the valves can leak, but the good news is that this process isn’t difficult to perform!