Just got my duetto, and the plan is to connect it to my 1/4" tubing to feed the pump directly. Speaking to the guys at Chris coffee they said the flow rate of a 1/4" is sufficient to feed the rotary pump. I didn't want to replace everything with 3/8".

My problem is that when i'm running off the plumbed line the pump make a not-so-pleasant noise...it's hard to describe. It doesn't sound so good, it's especially bad when refilling the boilers.. When running off the tank it's nice and quiet.
I read an old old post by Dan that one of his rotary machines complained loudly when fed through a 1/4" tube, and became quiet with a 3/8".

I haven't checked my water pressure, but i have my regulator maxed out (0-25psi regulator), and i have a flow rate of about 140ml in 10 seconds coming out of the plumbed in line.

Any ideas as to what it could be? I'm concerned that if i continues to test i might damage the pump if i'm starving it, as i've read that running the pump dry just for a second is a bad bad thing on a rotary.

Sounds like déjà vu all over again. Elektra A3 was fine pulling shots, but buzzed horribly when the boiler refilled. La Spaziale Vivaldi II - Steam Boiler Fill Noise Issue repeats the same refrain, though that one ended with a call to Chris' Coffee and a return.

Yes. It's a terrifying buzzing noise. Was the problem solved by using a 3/8" line? Should I spend $40 changing everything to 3/8?
I'll give Chris a call tomorrow to see what they suggest.

You may be hearing cavitation due to water starvation. If possible, try hooking up a 3/8" water line temporarily to see if the noise goes away.

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Are you sure you have the flow regulator in the correct direction? There is a right and wrong way to connect the regulator. If connect backwards the symptoms you described are likely to happen. Quarter inch is ok to run the machine off, PROVIDED you have ample flow rate.

I think Chris nailed it, and i'm a dumb dumb....i had the pressure regulator backwards.
It wasn't previously a problem b/c it was feeding a float system on my Tea, so low flow/pressure wasn't a problem.
Now pulling a shot it's nice and quiet. Sounds the same tank or plumb in.
Sometimes it's the simplest of things, and i feel like a putz!

Glad to hear that you have it sorted.

jasonmolinari wrote:I think Chris nailed it, and i'm a dumb dumb....i had the pressure regulator backwards.
It wasn't previously a problem b/c it was feeding a float system on my Tea, so low flow/pressure wasn't a problem.
Now pulling a shot it's nice and quiet. Sounds the same tank or plumb in.
Sometimes it's the simplest of things, and i feel like a putz!

Got it fixed, just when I was going to suggest an accumulator! (I use one at home since I needed it when using a floject (to eliminate pulsing) catering anyway)

thanks Mike...it's working well now