Chugger pump issue

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JMichael

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So, I have two chugger pumps and both worked very well up until a couple of weeks ago when one started locking up. By locking up, I mean the impellor will just freeze after about 20 minutes. The motor still runs but the pump quits.

Mike at chugger says it's because I need full port 1/2 ID quick disconnects because the 3/8 qd's cause cavitations which makes the pump impellor spin out against the pump head and lock up.

Anyone else have this issue? My other pump (chugger ) doesn't do this and the QD's are the same throughout the entire system.

Anyone know where to get full ported 1/2 QD's?
 
Hhhmm, I purchased a head unit from him for my 809 and running the McMasters-Carr QD's and havent had a issue with this yet. It will occasionally make a squealing noise when it first starts up. But I contribute that to air in the head.
 
Thanks guys!

Sam, in that thread it says that the sugars can cause this. This particular pump is used between my HLT and MLT and only moves water.
 
Hogcrewer said:
Hhhmm, I purchased a head unit from him for my 809 and running the McMasters-Carr QD's and havent had a issue with this yet. It will occasionally make a squealing noise when it first starts up. But I contribute that to air in the head.

I thought it might be air getting caught in the dip tube so I took it off but still had the same problem. It seems to only happen when the temps go over 160.
 
These little pumps can't truly cavitate. They can't pull enough suction to create a vacuum low enough to cause cavitation. The pump may have air in the head or the heat may be causing some distortion in the head causing it to bind and lock the impeller up. Does the flow sputter or make any bubbles before it stops or does it just lock up? The casting looks less than stellar on most of these from what I've seen, so I'd suspect it's an alignment issue. Can you move the rear can relative to the front volute cover if you take the head off?

Try taking the qd's off an just recirc hot water with the hoses and see if it locks up. If so then it's an alignment issue.
 
Check the alignment of the 4/6(volute) (ss chugger remake of the polysulfone/bronze march heads), 11, 12/13, and 14(rear can)
Page 2 for part # references.
http://www.marchpump.com/site/files/966/112170/382390/523930/Pump_Manual.pdf

By the sounds of it it's just heating up and binding the impeller on the shaft, or the thrust washer(11) isn't in the right spot at the front of the impeller(14).
 
These little pumps can't truly cavitate. They can't pull enough suction to create a vacuum low enough to cause cavitation. The pump may have air in the head or the heat may be causing some distortion in the head causing it to bind and lock the impeller up. Does the flow sputter or make any bubbles before it stops or does it just lock up? The casting looks less than stellar on most of these from what I've seen, so I'd suspect it's an alignment issue. Can you move the rear can relative to the front volute cover if you take the head off?

Try taking the qd's off an just recirc hot water with the hoses and see if it locks up. If so then it's an alignment issue.

What makes you say you can't get cavitation in these pumps? If you have enough restriction in the suction line and the vapour pressure is lowered due to it being hot water I could see it possible to cavitate the pump. Just saying.
 
Thanks guys!

Sam, in that thread it says that the sugars can cause this. This particular pump is used between my HLT and MLT and only moves water.

In addition to what WPStrassburg is telling you I'd also say that water has minerals which could be building up on the parts, as well as possible corrosion. I'd not put it past the China pump mfg to use less than stellar parts inside the Chugger.

My QD's are 1/2" but choke down to 3/8" at one point, I just don't have the issues from that restriction. Sometimes it takes me a few moments to get prime and then it works fine. (March pumps, my Chuggers are still in the box)
 
March only has suction lift ratings for their 7&7.5 series pumps, so I'd say the suction is nil on the 809 series.
http://www.marchpump.com/site/files/966/110094/376709/517837/March_Pump_Catalog.pdf

At 160 degrees the pump would have to be pulling 10psi+ of suction for it to cause cavitation(more than the 7 series 12'(~5psi)).
http://www.myplumbingportal.com/Articles/PME_Back_To_Basics/9c6955c9ff298010VgnVCM100000f932a8c0____
Sorry for the tiny graph, but it's a decent little writeup.

What you are needing to look at are the NPSH (net positive suction head) required for the pump. If the NPSH available drops below that required you will have cavitation. Small/long suction lines will reduce the NPSH, to combat this the pump can be mounted lower (in relation to the vessle) which will increase the NPSH available, or you could just increase/shorten/remove restrictions from the suction line. Also if there are any restrictions in the pump - say if there is a reduction in diameter at the inlet to the impeller - this will also cause a drop in pressure and could allow cavition to occur.

Edit: one thing is I don't think March would have/publish NPSH required for the 809,etc. series as I would imgine no real world application would be to interested in them, i.e. not many homebrewer or amatuer horticulturist is going to perfectly engineer their system, most would just put in bigger pipe (it says so in the march installation instructions) or drop the pump a bit more.
 
March only has suction lift ratings for their 7&7.5 series pumps, so I'd say the suction is nil on the 809 series.
http://www.marchpump.com/site/files/966/110094/376709/517837/March_Pump_Catalog.pdf

At 160 degrees the pump would have to be pulling 10psi+ of suction for it to cause cavitation(more than the 7 series 12'(~5psi)).
http://www.myplumbingportal.com/Articles/PME_Back_To_Basics/9c6955c9ff298010VgnVCM100000f932a8c0____
Sorry for the tiny graph, but it's a decent little writeup.

That first link you have there refering to the 7&7.5 pumps....the suction lift is only listed for the "SP" or self priming pumps. They have a built in 1 gallon jug on the front of the pump you would need to prefill with liquid for it to have a suction capability.
You can make some of our smaller pumps "self priming" by adapting our 750 priming chamber. Its not listed in that catalog link, but you can find it here:
http://www.marchpump.com/accessories/
Its the first picture of the white chamber. It was initially made for the 4&5 series pumps but will fit up to the series 6 pumps and you can adapt it for smaller pumps with reducers/adapters. With that chamber installed you can get 6-12' of suction list depending on the size of line used and what model pump its hooked up to.

As for these pumps not cavitating....they indeed can cavitate...well the HS ones can...but its on such a tiny scale you can barely see the bubbles created. You can test it if you have clear hose on the discharge...close off the inlet while its running...almost at shutoff you will see a small white discharge from the pump but it will pass very fast...and you will see it again when you start to open the valve as well.

-Walter
 
What you are needing to look at are the NPSH (net positive suction head) required for the pump. If the NPSH available drops below that required you will have cavitation. Small/long suction lines will reduce the NPSH, to combat this the pump can be mounted lower (in relation to the vessle) which will increase the NPSH available, or you could just increase/shorten/remove restrictions from the suction line. Also if there are any restrictions in the pump - say if there is a reduction in diameter at the inlet to the impeller - this will also cause a drop in pressure and could allow cavition to occur.

Edit: one thing is I don't think March would have/publish NPSH required for the 809,etc. series as I would imgine no real world application would be to interested in them, i.e. not many homebrewer or amatuer horticulturist is going to perfectly engineer their system, most would just put in bigger pipe (it says so in the march installation instructions) or drop the pump a bit more.

You are right on the mark! When a mag-drive centrifugal pump is in operation the impeller ideally spins on the shaft in a neutral position and has the ability to move forwards and backwards. When in that neutral position the pump is operating as a transfer pump. When you have allot of restriction on the discharge side (like if the pump is operating near dead head) then the impeller gets thrust to the rear of the pump housing and you could get premature wear of the back end of the impeller/pump housing. If you put a restriction on the inlet side of the pump....like a valve, too small a line, not enough NPSH, a clogging filter, etc.....then the pump starts to turn into a suction pump and the impeller is sucked up against its thrust washer. If left in this stage long enough some things can go wrong. Most common failure we see in this situation is the impeller has either worn itself out on the very front where it contacts the thrust washer....or the thrust washer is worn out/gone and the impeller starts to contact the front housing and starts de-coupling. Of course this is just a very basic explanation.

The next question I usually get from people after that explanation is "why is this pump better then other types of pumps like diaphragm or gear drive?"
And my response goes like this:
Well if properly setup and you don't use different chemicals then what you initially told us about that may cause compatibility issues with the parts inside....then the pump will 99% of the time outlast the motor in every situation. Every pump you look at will have an achelies heel....with our pumps we don't generate big pressure numbers, its all about volume with us....with a gear drive pump you will have shaft seals that WILL wear out eventually. With a diaphragm pump you don't get a smooth output as it pulses during operation. and is usually noisy with the rhythmic back and forth pulsing. A peristaltic pump will wear out the hose it uses internally. You as the customer have to figure out what exactly you are looking for out of the pump and buy accordingly.

-Walter
 
Thanks guys.

I'm going to try removing the QD's and barbs and see if that helps. If it works I'll replace my QD's with cam locks.
 
I finally wired up the plug on one of my Chuggers today. Being curious I took the pump head off for a look. I was amazed at how poorly all the parts are cast and machined. I am going to be surprised if this thing performs anywhere near the level of the March pumps.
 
I finally wired up the plug on one of my Chuggers today. Being curious I took the pump head off for a look. I was amazed at how poorly all the parts are cast and machined. I am going to be surprised if this thing performs anywhere near the level of the March pumps.

You didn't happen to take any photos? Would be great to see some of the inside of the pump. :mug:
 
also forgot to ask if the inlet tubing was securly attached to the inlet barb. I've had more trouble with air being pulled in and screwing the prime up then anything else. Maybe as your tubing warms up it softens and lets air in?
 
I am trying to remove the drive magnet (part 18 in the link) from a dead motor without any success.

Does anyone have any ideas for me? I pm'ed walteratmarchpumps about this but never heard anything back from him, so I am hoping someone on here might have an idea(s).

:mug:

Realy? i dont have any PM's and reply to any i get right away...hopefully i didnt mistakenly hit the back button instead of reply! Sorry :(

As far as removing the drive magnet off the shaft of the motor, the easiest thing you can do is use two flat head screwdrivers as pry bars under the base of the drive magnet up against the shaft of the motor and pry it off and up. Make sure to loosen the allen set screw that holds the magnet onto the shaft. If you have any problems or issues then send it back to me here and i can do it for you...if you are replacing the motor or something you will probably have a "fun" time trying to re-align the motor bracket properly.....you can send me the new motor with drive magnet and motor bracket and i can install it and align it for you for free...

-Walter
 
Walter, thanks for the feedback. I was not upset, FYI, just hoping someone might have answers; I know people do get busy and things (and the PM was sent on 2/1/11 at 3:57pm; maybe you did in fact hit back instead of reply).

I will try your advice, and contact you if I have issues. And I really appreciate your offer to send it in for free if need be.

Thanks.

:mug:
 
WPStrassburg said:
also forgot to ask if the inlet tubing was securly attached to the inlet barb. I've had more trouble with air being pulled in and screwing the prime up then anything else. Maybe as your tubing warms up it softens and lets air in?

I guess it's possible but I have clamps on and tightened down. I thought I was going to have to cut the hose to get it off the barbs.
 
If a 1/2" barb reduces the ID to 3/8, would a 5/8 reduce to 1/2? I guess my question is would increasing my hose ID to 5/8 be ok for the input/suction side on this pump or would it be too big?
 
If a 1/2" barb reduces the ID to 3/8, would a 5/8 reduce to 1/2? I guess my question is would increasing my hose ID to 5/8 be ok for the input/suction side on this pump or would it be too big?

Yes and this is the reason that I use 5/8" hoses throughout my system.
 
yeah but trying to find 5/8" valves, couplings, etc is a *****. might as well just step up to 3/4"

-=jason=-
 
yeah but trying to find 5/8" valves, couplings, etc is a *****. might as well just step up to 3/4"

-=jason=-

I think you may have missed the point. The hoses I use are 5/8" ID and the matching barbed fittings have an ID of 1/2". The valves and hard pipe are 1/2" ID. The end result is that everything throughout is not less than 1/2" ID. I had no problem locating fittings for the 5/8" hose.
 
I think you may have missed the point. The hoses I use are 5/8" ID and the matching barbed fittings have an ID of 1/2". The valves and hard pipe are 1/2" ID. The end result is that everything throughout is not less than 1/2" ID. I had no problem locating fittings for the 5/8" hose.

ahh gotcha.

-=Jason=-
 
The larger size of tubing and barbs didn't make a difference. They sent me another at no charge, which was really generous considering I bought it last summer. I hope to try it out this weekend.
 
No, I actually went back to the small hoses and quick disconnects as they worked better than the larger ones.

My last several brewing sessions have gone much more smoothly. I was getting close to going back to the good ol' cooler and kettle setup. All seems to be good now though so I'm keeping my cool setup... :D
 
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