Central Vac DIY Questions

[T-Rex]

Hi, I've been reading the content from you guys and thought I'd reach out with some specific questions.
I have an MD Silentmaster S44 purchased new in 2012. Motor died in 2019 and I replaced it with the Lamb 122525. It died again a few months ago.
I was thinking that these motors were not getting anywhere near the hours rated (we don't use it all that often but there is no way to tell actual hours). I was reading about replacing with other units, whether it be another MD, Drainvac, Cyclovac or Vacuflo (or even the OXO - oh no!).
So for S&Gs I decided to check the brushes and I've found one to have maybe 1/4" of carbon - and the other - gone! So I'm thinking maybe it was my fault all along not checking/replacing brushes but I didn't think I was even at 300-500 hours???

So, the rotor does look dirty but not really scored so I'm thinking now maybe I should just change motor out one for time for the latest 122685 for $150 (central vacuum online - is that place reputable? It is $75 less than MD direct). I'm also thinking about replacing the circuit board just so everything is new.

So my questions - about your recommendation... would you just refresh the parts for around $250 and just make sure in the future I check brushes every few years or would you recommend still replacing the whole thing?

The can is still in decent shape except for the foam is disintegrating. Is is possible to remove and replace that foam?

Thoughts/Opinions?

As fyi home is around 2900 sq ft and I have 3 inlets with longest around 50' of pipe. I was going to ask about bottom motor design, bags, etc. but that would not be necessary if I just refurb this unit... I live 10 minutes from Gator/Think Vacuums and was not impressed. Best option in store was a Drainvac for 1300 bucks.

Thanks!

 

[panasonicvac]

I'd say fix it up and give it one more try. Strange to hear this is the second time it's happened that quickly because it should last longer than that. But in all of honesty, this wouldn't be a SilentMaster or a single motor MD unit of my choosing. I was told once that CycloVac had a warranty for carbon brushes, either they used to do that or someone who told me that was misleading because they definitely don't cover it today. If a new unit is warranted, don't go for a DrainVac. That company and even Think Vacuums that they're sold from has been lacking lately.

 

[cheesewonton]

What exactly is wrong with the current motor? Brushes worn down? Bearing noise or bearings seized? Those motors can be rebuilt with new bearings and brushes and the commutator shined up with a stone for a lot less than buying a new one.

I would be tempted to investigate your central vacuum installation and plumbing to see if there is a restriction or some other factor that is causing excess wear on motors. Is the motor being adequately cooled? Are the bags becoming plugged starving the motor of airflow? It seems to me something is causing motors to fail and replacing the main unit may not solve the problem.

 

[T-Rex]

What exactly is wrong with the current motor? Brushes worn down? Bearing noise or bearings seized? Those motors can be rebuilt with new bearings and brushes and the commutator shined up with a stone for a lot less than buying a new one.

I would be tempted to investigate your central vacuum installation and plumbing to see if there is a restriction or some other factor that is causing excess wear on motors. Is the motor being adequately cooled? Are the bags becoming plugged starving the motor of airflow? It seems to me something is causing motors to fail and replacing the main unit may not solve the problem.

Thanks for the suggestions. It's been a few months but I just remember the motor quitting, maybe a smell but not sure if that was just the first one. I looked at the motor, shaft/fan spins freely. The commutator (I guess what the brushes rub against) is very dirt (guess carbon dust). Maybe some slight scratches but doesn't look gouged. Couldn't see how to get that out to clean it? I'd have to investigate the other options after it's running again. I can try to take some pics. One brush still had some carbon on it and other was completely gone. How long should those brushes last, ~800 hours? Is there a retrofit to add an hours meter to this unit?

Is there a big difference between the lamb motors 122525 and 122685? The 685 replaces the 525. Thanks...

Edit: Added pictures

 

[cheesewonton]

The commutator looks pretty bad. You could try putting new brushes in this motor, clean up the commutator and see what happens.

To clean up the commutator you would need what is called a commutator stone. The vac owner of the vac shop that has rebuilt motors for me cleans the commutator with the motor running by rubbing the end of the commutator stone on the commutator as the motor spins. It usually only takes a few seconds to make the commutator segments shine again. I have seen other techs take the motor apart, chuck the whole armature in a drill and use the drill to spin the armature while cleaning the commutator with a stone. I don't think you want to take it apart if the bearings are ok. Grainger sells commutator stones. A vac shop would have one they could maybe sell you. That is where I get mine. Try the easy and inexpensive things first.

 

[scvacuumguy]

This is one of the reasons they make central vacuum companies. Call your closest local person and have them come out. Most of the people on here do not own a central vacuum business or a vacuum cleaner store. You’re getting advice from other people who don’t have a clue

 

[Hatsuwr]

The commutator looks pretty bad. You could try putting new brushes in this motor, clean up the commutator and see what happens.

To clean up the commutator you would need what is called a commutator stone. The vac owner of the vac shop that has rebuilt motors for me cleans the commutator with the motor running by rubbing the end of the commutator stone on the commutator as the motor spins. It usually only takes a few seconds to make the commutator segments shine again. I have seen other techs take the motor apart, chuck the whole armature in a drill and use the drill to spin the armature while cleaning the commutator with a stone. I don't think you want to take it apart if the bearings are ok. Grainger sells commutator stones. A vac shop would have one they could maybe sell you. That is where I get mine. Try the easy and inexpensive things first.

Any reason not to just use something like 1000-2000 grit sandpaper? I usually throw rotors on my drill press and polish them with that. I've heard concerns of particles getting embedded in the copper, but I've never had excessive brush wear after using sandpaper.

 

[cheesewonton]

Any reason not to just use something like 1000-2000 grit sandpaper? I usually throw rotors on my drill press and polish them with that. I've heard concerns of particles getting embedded in the copper, but I've never had excessive brush wear after using sandpaper.

I would never do that. Embedded particles are a concern especially if they manage to connect across segments as is too much material removed from the commutator and the problem of possibly leaving deep grooves in the commutator. Just me but I use the right tool for the job, a stone specifically designed for cleaning up commutators. You rub the commutator while the motor is running. Only need a few seconds to clean it up nice with minimal wear.

 

[panasonicvac]

One safer way to clean the commutator without taking the armature apart or turning it on is to use a wet/dry vac with a 2 1/2" hose and seal the end of the hose where the fans are at and the motor would spin at a reverse direction. Then I'd use a cleaning stone and give the commutator a good polish for like a few seconds. I don't always do it but I've had success with no issues whatsoever. I find polishing it with the motor on is the best way to do it. I used to work at an MD dealer and I can say that based on your description including photos, there's no need to do a service call or bring it in the shop to have someone else do it if you're a handy person, this is an easy fix. Even MD themselves says you can replace a whole motor by yourself if you wanted to.

 

[T-Rex]

This is one of the reasons they make central vacuum companies. Call your closest local person and have them come out. Most of the people on here do not own a central vacuum business or a vacuum cleaner store. You’re getting advice from other people who don’t have a clue

I appreciate your reply but 1. The local store here sucks (no pun intended). The one and only MD dealer who apparently works out of his house never returned my call. I am very handy, have somehat of a clue but was just looking for recommendations/opinions. Based on the few replies it appears some people certainly do have a clue - maybe not store owners or experts but certainly knowledgeable.

Anyway, to close this out... I bought a new motor and extra brushes from CVO, which looks like it may be related to MD since shipping label was from MD??? I also ordered some 1/2" foam / sound deadener from Amazon. I cleaned up the old commutator the best I could and put in the new brushes to try it. It ran but not full speed and threw off a ton of sparks and snap, crackled and popped - certainly was not fixed/useable. I tested the old board and it worked fine so just kept it for now.

I cleaned up the metal can and replaced all the disintegrated foam with the new stuff. I also used it as a nice big gasket for the new motor. Wired it back up and tested motor and it worked great. Reassembled all and it seems good as new for now. So for ~ $200 I should be good for 5 years or so and maybe longer if I replace the brushes early. May not be as powerful but it's a decent solution instead of paying 5x that for a new vac.

Thank you to those who took the time to reply.

 

[centralvacs1928]

I'm glad to hear you got your S44 back up and running with a new motor. Money well spent, IMO. As much as I love MD machines, that particular unit did suffer from motor longevity issues. I loved the performance and sold a good handful, but when failures started happening (although covered under warranty) I started recommending other models in the lineup...either the old S2 (lower performance but excellent lifespan) or the M85/F650 (still a go-to for me...amazing performance and surprisingly long life for a "cheaper flow-through" motor). Once the M715 became available, that unit became a top choice also for larger homes, retractable hoses, even commercial applications...the motor in that unit has excellent performance thanks to beefier impellers, and incredible life expectancy.

 

[Hatsuwr]

I'm glad to hear you got your S44 back up and running with a new motor. Money well spent, IMO. As much as I love MD machines, that particular unit did suffer from motor longevity issues. I loved the performance and sold a good handful, but when failures started happening (although covered under warranty) I started recommending other models in the lineup...either the old S2 (lower performance but excellent lifespan) or the M85/F650 (still a go-to for me...amazing performance and surprisingly long life for a "cheaper flow-through" motor). Once the M715 became available, that unit became a top choice also for larger homes, retractable hoses, even commercial applications...the motor in that unit has excellent performance thanks to beefier impellers, and incredible life expectancy.

Motor longevity information would be really nice to have available. Do you have any resources on that? I'm especially interested in the Lamb 8.4" ones, and in particular, the 122501 that I'm planning on putting into my CV350. It's apparently the same motor used in the Vacuflo 77800 and DB8000 as well as the AirMaster XL A715h.

 

[centralvacguru]

Typical central vac motors are rated to last about 800-900 hours. Interestingly on some of the thru-flo motors, if they had good filtration and a properly working air relief valve, our bench tests got around 1420 hours! We bench-tested the 8.4 motor and got over 2200 hours and that is consistent with what Ametek shared with us.

The 8.4 has the same bolt pattern as the old 7.2" motors so with good gasketing, you should be able to easily make it fit. One other concern though is that you make sure the cooling air intake is separated from the cooling air exhaust from the motor. You do not want this recirculating as it will reduce the longevity of the motor. This is why Modern Day prefers to put the motors on the bottom of the tank rather than the top. The cooling air intake is then at the lowest point in the installation location, bringing in the coolest air possible. Hot air rises so most of the hot exhaust air from around the unit and cannot be sucked into the cooling air intake. If the motor is put on top of the unit, the hot air rising around the unit easily gets sucked into the cooling intake and makes the unit run unnecessarily hotter!

 

[panasonicvac]

Personally, I'd rather replace the bag on top instead of the bottom. And I agree that it's better to put the motor on the bottom instead of on top. On my SilentMaster that I used to have, we put the bags on top of the unit which wasn't a problem because there's no cooling vents to block off. This thread has gotten me even more curious of what my actual SilentMaster model was. It for certain wasn't an S5 and it was for certain 120 volt because the cord was black. This was the one from our last cabin. I have the current owner's contact number so I'll probably reach out to them and request to send me some pictures of the info sticker.

 

[centralvacguru]

Based upon the logo on the unit it looks like it was from about 2005 and was likely our 2-Motor Model S2. It had great CFM and lower waterlift but operated on a 20Amp 12o volt circuit.. You can tell if it is a 2-motor by lifting the lid and pulling all the filters out. If it had two motors with a black cord, it was definately a Model S2.

 

[Hatsuwr]

Based upon the logo on the unit it looks like it was from about 2005 and was likely our 2-Motor Model S2. It had great CFM and lower waterlift but operated on a 20Amp 12o volt circuit.. You can tell if it is a 2-motor by lifting the lid and pulling all the filters out. If it had two motors with a black cord, it was definately a Model S2.

Does Ametek still make 20 A motors (or 240 V ones around 10 A)? I feel like I went through every 7.2" and 8.4" one on their website and only saw ~15/7.5 A max.

 

[centralvacguru]

That's a tricky question! They can make motors with high AMPS by simply making them innefficient. I want to say the largest we use would be 16 Amp as that starts to challenge the limits of the mini-breakers on our boards. #122650 https://builtinvacuum.com/product/122650-lamb-vacuum-motor/?c=vacuum-motors&s=models As far as efficiency for the Amps used, hands down the 8.4 produces the best stats for normal household vacuuming in my opinion.

 

[panasonicvac]

I think my first visit to the cabin with the unit installed was back in 2004 but maybe it was 2005, I can't remember now. I thought maybe it was a single motor unit cause I couldn't recognize if two motors were running at the same time. Who knows but I think I'm gonna reach out anyways. It was a overall good system. There were definitely some things I would've done differently if I could go back in time and change it like adding more inlets and put in a 240 volt S5 unit instead when it was under construction but I thought it was the perfect vacuum for the cabin nonetheless. I wish we had a second SilentMaster put in at the shed next to the cabin as I remember we had to borrow a portable one time to clean out some animal mounts and we nearly broke the vacuum when it accidently got dropped. But I honestly liked the idea of just buying a upright Lindhaus Healthcare Pro or Valzer instead as a second vacuum for the cabin since it can be safely used as a backpack.

 

[Hatsuwr]

They can make motors with high AMPS by simply making them innefficient.

True haha. When I was browsing I was more looking at peak performance than efficiency, but I definitely saw some that did not justify the amount of power they used.

I looked around more on Ametek's site and found the 122661 that uses 17.5 A with a 2" orifice. Nice CFM rating at that operating range, but the vacuum pressure suffers a bit compared to others as the restriction increases.

Taking the 122501 again, both that and the 122661 produce 704 air watts at a 0.875" orifice, but the 122661 draws 15.3 A while the 122501 draws 14.8. Anything more restrictive and the 122501 has a higher air watts rating.