Central Vacuum
 

Hi,

I just bought a central vac, and although it's supposed to be 67 db I found it to be quite loud for my taste. It's a good little unit, made in Canada (I should say assembled in Canada, because most components are actually made in Mexico). The motor is rated at 537 airwatts (whatever that is), but it's a 10 amps motor.

It is badly designed as far as soundproofing goes. The motor is located in the top of the canister with the exhaust port, but there's also the controller there with slots in the canister so air can exits directly that way. There is also a double pane top lid with a 4 inches hole in the bottom pane so air can also exit that way. The exhaust port has a muffler mated to it, but with all the other openings, running with or without the muffler didn't make a difference on the noise level.

You can see what I'm talking about on the following pic.

http://ecorenovator.org/forum/attach...1&d=1254098063

Anyway, I wanted to make it quieter, so the first step is usually to seal the thing. So I sealed the top lid slot and the numerous small slots near the controller and it was noticeably quieter. Before the tape it was quite annoying, now it is acceptable. And there is now a difference in sound level when I put on or take off the muffler.

But then I was wondering what happened with the inside temps. So I measured the temps on the side of the canister, in the top hole inserting the probe in the top lid slot, and inside the exhaust stream in the muffler. I first left the unit running for half an hour before taking the measurements.

Stock casing: 49 C / 120 F
Stock top lid: 59 C / 138 F
Stock exhaust: 60 C / 140 F

Taped casing: 49 C / 120 F
Taped top lid: 61 C / 142 F
Taped exhaust: 62 C / 144 F

So, am I right to assume it is safe to have the unit running with all slots sealed but the exhaust port?

I'm sure the unit can handle 4 degrees more easily. Just as long as you're sure those are max temperatures.

I think I'm going to try sticking Dynamat all around inside the top canister where to motor is. Also, the exhaust port could use a little tweaking, it's just a straight PVC pipe extending a couple inches into the canister. I think it would benefit having its end shaped as a bellmouth.

BTW, do central vacuums usually use less electricity than other types of vacuum cleaners?

I guess it depends on the model but probably not. The one the came came with my house has a transformer that's plugged in 24/7. The transformer uses 10 watts in just waiting for me to use it (which is never). I just use a shop vac on the hardwood, tile and vinyl. My wife vacuums the carpets with a canister vac. The central vac has been unplugged for a couple of years but it will come in handy as selling feature when we eventually sell.

The only central vac I have experience with is a kit that a friend bought to be installed in a house that he subdivided into apartments. The kit would draw vacuum against closed ports, and at a certain vacuum level, the motor would shut off. Of course, the second someone hooked up the hose and turned the valve on for the vacuum, the motor would start again. When you're done vacuuming, you just turn the hose valve back off and disconnect the hose, and the motor will continue running for a second to pull vacuum against the valve again, until the sensor tells it that the system is closed, and then it would shut off. I'm not sure what kind of energy it used, though.

I'd imagine a central vac would take a bit more power simply because it has to suck the debris so much farther than a normal vacuum. If you really want to check, and it would be cool if you did, hook up the vac system to a kill-a-watt and report the power usage. We can compare that to a normal vacuum cleaner then.