# Pierburg CWA-50 pump not running close to 100%



## Caps18 (Jun 8, 2008)

This is a good description of the coolant pump, but I'm wondering what I need to do to make it work.

http://webpages.charter.net/n8nxf/EVTV Pierburg CWA-50 Coolant Pump.pdf

Now, I just applied 12.6V to the Vin, Lin, and PWM wires, and it did turn on at 0.5A. And it wasn't really vibrating, but it was making some noise. I was expecting it to be around 6.5A and to move the antifreeze. But, it seems to be in a power save mode instead of a 100% mode.

I'm guessing that I either need to do something to fix the PWM signal or could it be a problem that there is air on the output side of the pump?

Is anyone else using this type of pump and have it working?


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## Hollie Maea (Dec 9, 2009)

Caps18 said:


> This is a good description of the coolant pump, but I'm wondering what I need to do to make it work.
> 
> http://webpages.charter.net/n8nxf/EVTV Pierburg CWA-50 Coolant Pump.pdf
> 
> ...


The Lin is a communication pin...you don't want voltage on it. That's probably the problem. I've had no problems running these pumps with 12V to the Vin and PWM wires, keeping pin 2 unpopulated.


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## Caps18 (Jun 8, 2008)

I hooked up pin 4 and PWM Pin 3 to 12V, but it still does the same thing. I haven't cut the wires short yet, so I have 25ft of 18 gauge wire, but I wouldn't think the voltage would drop that much over that length. I hooked up pin 3 (PWM) directly to 12V and with a 1k resistor attached (to the end of the pin 3 wire), and I got it up to using 0.75 A. It still seems like it makes a quiet buzzing sound, but doesn't move any fluid. 

Do I need to connect the Lin wire to ground? Or did I blow up the electronics by applying 12V to it?

I will try and make the 555 circuit that was suggested in this document tonight and see if that works.

I do have it mounted horizontal, and I'm not sure if I guessed that the coolant goes into the intake that is also horizontal and the outlet is pointed downward. Will it have any problems pumping a little bit of trapped air, or do I need to make sure that the coolant has reached the pump?

http://webpages.charter.net/n8nxf/EVTV Pierburg CWA-50 Coolant Pump.pdf


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## Caps18 (Jun 8, 2008)

Update to my last post:

It works now! The problem was that from the reservoir to the pump, there was a hose that went upwards. This trapped a pocket of air I'm guessing. Because I hooked it up again to 12V with the 1K ohm resistor on the PWM wire on pin 3 and the pin 4 as +12V and it still didn't work. But, once I took off the hose going to the inlet of the pump, I could feel that there was some suction, but it took a while for any fluid to come out of the hose. Once I reconnected the hose, the pump started pushing the coolant around the system and back into the reservoir. It uses 4.0 Amps @ 12.44V, so it is around 50W

Now, I have to fix the one leak I see. And I will have to test how I should switch the pump on and off. Or do these controllers need constant cooling, even in the snowy winter months?

I could hook up one of these to monitor the temperature and turn it on when it's temperature is high enough.
http://www.lightobject.com/JLD7100-PID-Temperature-Controller-P44.aspx


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## Caps18 (Jun 8, 2008)

I'm not sure it will help anyone else, but this is the wiring diagram and notes that I wish would have been included when I bought mine.


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## Caps18 (Jun 8, 2008)

I should have added a 5A fuse to the yellow wire close to the end of it. I will be using one when I connect it to the rest of the vehicle wiring.


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