Central vacuum

[cheesewonton]

For a well installed system, I don't think the ideal power of the power unit corresponds very well to home size, for the vast majority of homes at least. There losses in pipes in the walls should be relatively small compared to the hose and cleaning head/attachments.



That's interesting. I wonder if you would get more cleaning-relevant performance from having the two motors in series instead of in parallel.

My question is, do you really have more cleaning power at the end of a 30 something foot long central vacuum hose after it has gone through another 50-100 feet of pipe in your walls than you have at the end of the hose from a good canister vacuum? Are all those motors, tubing, wiring, extra power consumption and money getting you more cleaning power at the end of the hose?

 

[Hatsuwr]

My question is, do you really have more cleaning power at the end of a 30 something foot long central vacuum hose after it has gone through another 50-100 feet of pipe in your walls than you have at the end of the hose from a good canister vacuum? Are all those motors, tubing, wiring, extra power consumption and money getting you more cleaning power at the end of the hose?

Personally, my favorite thing about central vacuums is that you can vent the exhaust air outside, but regarding performance, yes, you will be getting more cleaning power at the end of the hose in most situations.

Usually when using a vacuum, you will be creating a restriction around the area being cleaned to increase the air speed at the area being cleaned. This restriction means you will have a much lower airflow rate than just an open hose end. Because of this lower airflow rate, the pressure losses in the pipes and hose will be decreased.

These losses are more significant at higher airflow rates. Sometimes I use my central vacuum for fume extraction when soldering — that's about the worst case for a central vacuum, but I'd guess that even then it would beat (or at least be competitive with) most canister style vacuums. Plus, with the canisters you need to take into account power loss from voltage drop in the power cable. This loss will be greater with more powerful motors and during higher loads, but you could be looking at a 10%+ loss in power from this.

 

[centralvacguru]

Any chance you have a picture of the old MD unit? What is the serial number?

 

[ultralux88]

It's a model E, serial 188. I know I talked to you about this one a couple years ago. Found on Facebook marketplace out of Colorado Springs. Was quite a treat, as I was assuming I'd have to go through all kinds of nonsense to find one and get it out of California somewhere, as an early MD was something I did really want.

 

[cheesewonton]

Personally, my favorite thing about central vacuums is that you can vent the exhaust air outside, but regarding performance, yes, you will be getting more cleaning power at the end of the hose in most situations.

Usually when using a vacuum, you will be creating a restriction around the area being cleaned to increase the air speed at the area being cleaned. This restriction means you will have a much lower airflow rate than just an open hose end. Because of this lower airflow rate, the pressure losses in the pipes and hose will be decreased.

These losses are more significant at higher airflow rates. Sometimes I use my central vacuum for fume extraction when soldering — that's about the worst case for a central vacuum, but I'd guess that even then it would beat (or at least be competitive with) most canister style vacuums. Plus, with the canisters you need to take into account power loss from voltage drop in the power cable. This loss will be greater with more powerful motors and during higher loads, but you could be looking at a 10%+ loss in power from this.

I don't get it. We are talking literally the exact same attachments, wands and power nozzles on the ends of a central vacuum hose or a canister vacuum hose. In fact several of my vacuums like the Oreck Dutch Tech, Patriot and Miracle Mate literally have standard Plastiflex central vacuum hose handles and I use a variety of different central vacuum wand and power nozzle combos with them. How is this different from a central vacuum? Where is the difference in restriction?

 

[Hatsuwr]

I don't get it. We are talking literally the exact same attachments, wands and power nozzles on the ends of a central vacuum hose or a canister vacuum hose. In fact several of my vacuums like the Oreck Dutch Tech, Patriot and Miracle Mate literally have standard Plastiflex central vacuum hose handles and I use a variety of different central vacuum wand and power nozzle combos with them. How is this different from a central vacuum? Where is the difference in restriction?

I'm not talking about a difference in restriction between the two, I am talking about the intentionally created restriction that directs the airflow to the area being cleaned. That particular restriction can definitely be assumed to be the same between the two types of vacuums.