Pump makes "air-inside-pump-house"-sounds when throttling back on output valve

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Smellyglove

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If I run straight water through the March, and throttle back, I guess there's some sort of turbulence going on because I can soon after hear air in the house.

The valve is connected directly on to the pump. Will it help if I add 2" of "extension" and then mount the valve there?
 
Unless your inlet plumbing is sucking air, what you're more likely hearing is not cavitation but the rotor magnet decoupling from the drive magnet. They're designed to do that, and depending on the degree of restriction you can actually modulate the rate that the magnets de-couple/re-couple.
Adding a riser isn't going to change that...

Cheers!
 
If I run straight water through the March, and throttle back, I guess there's some sort of turbulence going on because I can soon after hear air in the house.

The valve is connected directly on to the pump. Will it help if I add 2" of "extension" and then mount the valve there?

On the valve on the output or input side? Ed
:mug:
 
It's air-sounds I've been battling this pump for god knows how long (own thread). I know every sound it makes :) Decoupling has a lower tone to it, i think.

It's just there with water, not wort.
 
Okay, I'm going to be the d*ck who wants you to post a pic of the pump and valve. There should be no air if the valve is on the out side when you throttle back.
 
It's on the output-side.
I have an inline Chugger, but I'm guessing it's pretty much the same type pump. I was having the opposite problem recirculating hot wort, when I fully opened up the valve, I got cavitation and it would stop pumping. In my research, I found there shouldn't be any elbows on the inlet side that restricts flow, so I now have a straight shot in from the kettle (doing BIAB) to a ball valve, straight out to the top of the kettle. That seems to have fixed the issue. As @day_trippr said, maybe you have an air leak. You don't have any elbows on the pump, do you? Ed
:mug:
 
There's an elbow, I know.. But I've added some pieces to get it away from the pump head.

Nevertheless. It works flawlessly in all other situations, and this isn't a big deal. For me the difference would be If I can throttle back to desired flowrate when I prep the brewery on a timer the night before, or when I get down in the basement in the morning. So, I will not do any mods other than maybe placing the valve further from the pump.

2.jpg
 
There's an elbow, I know.. But I've added some pieces to get it away from the pump head.

Nevertheless. It works flawlessly in all other situations, and this isn't a big deal. For me the difference would be If I can throttle back to desired flowrate when I prep the brewery on a timer the night before, or when I get down in the basement in the morning. So, I will not do any mods other than maybe placing the valve further from the pump.
I'm really thinking the valve on the outlet side isn't the problem. Here's my setup (I keep the head disassembled until I'm ready to brew.) My inlet is at 9 o'clock, and outlet at 3 o'clock. Thinking back, you said it's only doing this with water, but not wort. I'm wondering if the lower viscosity of water creates cavitation issues when you throttle back (i.e. reduce throughput?) A real head scratcher this one is. :confused: Ed
:mug:

Pump head.jpg
 
I'm pretty sure it's a viscosity-issue, yes. But. We can lay this one dead. It's not a big issue, and since people are starting to discuss things I've been over before when I had a "real" issue with the pump.. We can let this thread slip.
 
Hi all, haven't been on here in a while as i haven't been getting any notifications in any of the threads i was subscribed to :confused: but anyway...fist thing i would do is verify you are getting air in the plumbing.....easiest way to do that would be to put the discharge line under water and let the pump run wide open for a little bit to work all the air out of the system....then close the valve and see if you start seeing air bubbles coming out of the discharge line underwater.
Second thing is are you sure its actually in the pump head or could it possibly be the low pressure zone on the outlet side of the vale causing the noise? Easy test it so move the valve to the other end of the discharge line and repeat closing it like you've done before.
Other then that, if there is actually air getting into the pump its either from a restriction on the inlet side or a leak in the fittings somewhere introducing air into the system.....
 
Hi all, haven't been on here in a while as i haven't been getting any notifications in any of the threads i was subscribed to :confused: but anyway...fist thing i would do is verify you are getting air in the plumbing.....easiest way to do that would be to put the discharge line under water and let the pump run wide open for a little bit to work all the air out of the system....then close the valve and see if you start seeing air bubbles coming out of the discharge line underwater.
Second thing is are you sure its actually in the pump head or could it possibly be the low pressure zone on the outlet side of the vale causing the noise? Easy test it so move the valve to the other end of the discharge line and repeat closing it like you've done before.
Other then that, if there is actually air getting into the pump its either from a restriction on the inlet side or a leak in the fittings somewhere introducing air into the system.....

Thanks for your input. It's always great to see company rep's on here, and that you guys do care.

First. I'm good. It's not a major issue.

Second. It's in the pump head. No doubt. I know the different sounds this pump makes as if it was my baby. Heck, I can tell what the spin-down sound will be like everytime I turn it off given a different flow in my system :)
 
Thanks for your input. It's always great to see company rep's on here, and that you guys do care.

First. I'm good. It's not a major issue.

Second. It's in the pump head. No doubt. I know the different sounds this pump makes as if it was my baby. Heck, I can tell what the spin-down sound will be like everytime I turn it off given a different flow in my system :)

Have you taken the pump head apart to check inside? Maybe the thrust washer is worn out and allowing the impeller to contact the pump head? If you want to send it back to us here feel free to give us a call....ask for Wayne in the service dept and tell him you want to send it back for evaluation and that you talked with me. When he gets it back he will take it all apart and spec it out to make sure it all within tolerance....then put all back together and test run it on our tank here for performance...
 
Have you taken the pump head apart to check inside? Maybe the thrust washer is worn out and allowing the impeller to contact the pump head? If you want to send it back to us here feel free to give us a call....ask for Wayne in the service dept and tell him you want to send it back for evaluation and that you talked with me. When he gets it back he will take it all apart and spec it out to make sure it all within tolerance....then put all back together and test run it on our tank here for performance...

Thanks, but I'm in Norway ;)

Anyhow, it works fine for my application. But, today it sounded like decoupling when I throttled back, then came sound of air. The pump still keeps running and pumping. It's just that I have memories of terror with sounds from that pump other than the fan, so I'm kind of on edge, but it works.

Btw: I've read close to the entire thread where you're up for Q&A about the March pumps. Good read.
 
When it spins down with air inside the pump head I can hear the sound of what I guess is the impeller making contact with the pump head. This pump has taken a beating for three years now and then when it would suddenly jam and make that squealing-pig sound. But as soon as it gets a liquid with some viscosity (the wort) it runs absolutely fine at all flowrates.
 
De-coupling would be a go - no/go situation....if the mag-drive de-couples then you loose all pumping action.
Can you make a video of it during the issues and email to me? my work email is wwojcik @ marchpump.com (minus the spaces so the internet spammers dont harvest it :D )
 
De-coupling would be a go - no/go situation....if the mag-drive de-couples then you loose all pumping action.
Can you make a video of it during the issues and email to me? my work email is wwojcik @ marchpump.com (minus the spaces so the internet spammers dont harvest it :D )
'
Aha. Well it rattles. I thought that sound was on the verge of decoupling so it knocks against the housing. I guess a sound sample is more worth than a video so I'll find my recording-gear and record it in action during next brewday. Thanks a lot.
 
If you have a cell phone with a camera you should be able to record a short clip and shoot it off or text it to an email address. :)
have you taken the pump apart at all? maybe the thrust washer inside is gone and the impeller is rubbing against the pump body?
 
If you have a cell phone with a camera you should be able to record a short clip and shoot it off or text it to an email address. :)
have you taken the pump apart at all? maybe the thrust washer inside is gone and the impeller is rubbing against the pump body?

Yeah I have, to see what clogged it a few brews back. But I don't know what the thrust-washer is..
 

Huh! So there's supposed to be a small washer there. There is no such thing in my pump. A loose washer between the impeller and the shaft?

I think I've lost mine years ago, because I can't remember it ever being there. I guess that's why the impeller has a shape where there's two "semi-cirkles" on it which sticks out. Guess the thrust washer is the same diameter as those.
 
Huh! So there's supposed to be a small washer there. There is no such thing in my pump. A loose washer between the impeller and the shaft?

I think I've lost mine years ago, because I can't remember it ever being there. I guess that's why the impeller has a shape where there's two "semi-cirkles" on it which sticks out. Guess the thrust washer is the same diameter as those.

Yes there's normally a teflon washer there between the impeller and the pump head. If that's gone then the impeller could be rubbing against the pump head causing the issues. If you are in a bind and want to do a quick fix try going to the local hardware store and finding a stainless washer....it needs a .250" hole to fit on the shaft. The Outside diameter of the washer is 13/32" so try and get as close to that as possible....too big and you can start blocking off the inlet opening of the pump. And the thickness of our washer is .050" or about 3/64"
 
Yes there's normally a teflon washer there between the impeller and the pump head. If that's gone then the impeller could be rubbing against the pump head causing the issues. If you are in a bind and want to do a quick fix try going to the local hardware store and finding a stainless washer....it needs a .250" hole to fit on the shaft. The Outside diameter of the washer is 13/32" so try and get as close to that as possible....too big and you can start blocking off the inlet opening of the pump. And the thickness of our washer is .050" or about 3/64"

I can still brew with it so I'll just let it be until i maybe can get hold of a proper replacement part. I live in Norway, EU. Do you have any tips where I can get hold of a replacement?
 
How much can these dimensions be off? I'm in Europe so it's not the simplest task to find a SS washer with those dimensions. What i've found is:

.250" = 6.35mm
13/32" = 10.318mm
0.050" = 1.27mm

There's a hardware store which sells washers sized: 6.4mm x 12mm x 1mm. I have to buy them in packs of 50 so if this is an immediate no-go then I will look elsewhere. It's the OD which is the biggest difference.
 
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