LiterMeter III - Vibration

[RedEDGE2k1]

I received my LiterMeter III and extra external pump today and now have everything hooked up.

1) I read to run the pumps dry for 20 minutes before calibrating, however when run them dry the unit sounds like it's STRUGGLING to turn the shaft/rollers and I'm afraid I'm going to burn up the motor. Is this normal?

2) When I hook up tubing and run water through the unit during the break-in period, the output tube vibrates like crazy and the water is coming out of the output tube in quick spurts rather than a solid stream of water. I have the intake tube fully submerged in water, and there is no air leaks on the intake side. Is this normal?

3) Overall, are the tubes supposed to vibrate like this? Both the built-in pump and external pump do the exact same thing, so maybe it's normal and I just didn't expect it to vibrate so much.

Thanks for the help-
Dustin

[SpectraPure]

1) I've never had it described as "struggling" before, so I'm not quite sure what you mean. Go ahead and run the calibration routine and tell me what both pumps do in ml/min.

2) Peristaltic pumps do spurt more than flow. It's in the nature of how they work. It shouldn't be a problem. The LM3 typically runs for only a few seconds at a time.

3) Those 40 psi squirts do need to be corralled. It's OK if the tubes flop around, but they are usually hitting something. That's why we recommend tying the tubing to a leg or other support surface with velcro, ty-raps, etc.

Scott
SpectraPure, Inc.

[RedEDGE2k1]

By "struggling" I mean it sounds like the motor is being bogged down and isn't strong enough to turn the rollers dry. It runs fine when water is running through, however. I dismantled and reassembled the roller body per the manual but it didn't help.

[SpectraPure]

Run the calibration routine.

Scott

[RedEDGE2k1]

I think both pumps are perfectly fine, I just wasn't expecting the vibration in the output line. But after thinking about the physics behind how these pumps work, it makes sense that they would vibrate and the flow would be in "spurts."

After calibrating the internal and external pumps, the unit displayed a flow rate of 247 for the internal and 189 for the external pump. Is it normal to have such a large difference in the two?

[SpectraPure]

We do see some variance. That's also the nature of p.pumps. If I had to guess on an average, it would be about 200. They may not be quite broken-in yet. Run 'em for a couple more hours before settling on those numbers.

Scott