Just moved homes and went from plumbed in to tank water use. Upon doing so my Alex Duetto II pump seemed to have gotten louder. I opened it up to find one of the gauge lines was vibrating against something, bent it out of the way and it was quiet again.

This week the pump got noisy again. Opened it and can't find/see anything rubbing. Makes the same noise even when i hold the pump to try to quiet it down.

Listen in this video. Any ideas what it might be? Help troubleshooting?

This was just pulling water, but the sound is similar with pulling a shot. Noise seems to come and go as you hear in the video.

Jason,

I am not an expert on this machine but I did have one for about a year.

A bit more information that might help the community help you.

Are you getting a normal flow or water from the group? Do you have stuttering or water flow that is not smooth? Do you know what is pressure of your line into the machine? Do you have filters in the line to the machine?

What does the water pressure read? Does the gauge display properly?

Is the line that you bent crimped in any way?

How large is your water supply line and what is your input pressure? It sounds like you have a cavitation problem which is caused by inadequate water flow to the pump.

That's what i thought too...but it's using the tank now. Internal reservoir.

smite wrote:Jason,

I am not an expert on this machine but I did have one for about a year.

A bit more information that might help the community help you.

Are you getting a normal flow or water from the group? Do you have stuttering or water flow that is not smooth? Do you know what is pressure of your line into the machine? Do you have filters in the line to the machine?

What does the water pressure read? Does the gauge display properly?

Is the line that you bent crimped in any way?

water flow from group is normal. gauges read proper pressure (8.5 bar). It's running off the tank now.

The line i bent was the pressure line leading to the gauge and all i did was slightly uncoil the coils in it to move ti away from another line...so no crimps.

I guess the best thing i can do is to see if there are any issues in the water feed between the tank and the pump?

any other thoughts?

You should have posted a video of the sound without your hand on it.

Does the noise you're referring to sound the same with the machine cold vs. in working temperature?

LaDan, hand or no hand the noise is identical. Noise is the same hot or cold.

I have a small update from tonight's investigation. I took the side panels off to look for kinked lines. Nothing to be found, but what i did notice is that as i was looking around i was cycling the pump on and off, and after about 10-15 cycles the noise stopped happening.

I then went to refill the tank and removed the water line from the tank, which caused a bubble to form in it as the water dribbled out of the end of the silicone line. Started the pump again and just as the air bubble got sucked up into the pump the noise started again.

I repeated the 10-15 cycles and the noise seems to have gone again. It's almost like there is a bubble somewhere in the pump that doesn't get pushed out for a number of on/off cycles.

So the pump is quiet now, i'll see if in the morning it's quiet.

Mine always makes a different sound when the boilers are cold. Plumbed machine. First thing in the morning I run a few seconds of water thru it to "bleed" it for any air pockets and empty tubes & crevices. Switch is off, and I lift the lever to push thru the line-in 4 bars pressure water. Then I lower the lever, turn the machine on, and do that again now pushing water with the pump. It makes a different (louder) sound for some reason. 15 minutes later when the machine is hot, the sound is quieter.

I do this to "prime" the machine.

You might want to try this procedure to make sure everything is full of water (no air bubbles) before you start your pump.

I would but i'm not plumbed in anymore...any i don't think the tank will push much water through at 1/2 lever