central vacuum piping question

[mac]

We want to replace the steel piping used on Spencer central vacuums. These are in rental car facilities and have 8 drops on them. The problem is that because they are steel, the inside quickly rusts from sucking all of the sand. The rust traps the other stuff sucked up and then we have to go out and auger the lines. So I was thinking of using pvc lines that wont rust and start the process. The problem I'm having is matching the OD of the steel pipes with the OD for the pvc. Trying to find an OD of 5", 4", and 3", or something real close to it. Any thoughts on this?

 

[Kenneth]

Are your concerns in matching the OD size based on being able to couple them together? I would be more concerned with the ID size myself because it will change the amount and size of debris you will be able to flow. You can usually find rubber adapter boots to make anything work that you can come up with. That's my 2 cents.

 

[Washmee]

The standard size of inlet piping for most central vacs is 4 inch. You can use 4 inch for the first 20 feet of a single run and then drop down to 3 inch for the remaining run. ABS works fine and is quite a bit less expensive than PVC. Just use a rubber sleeve to connect the piping to the producer.

 

[robert roman]

Central vacuum systems are typically designed to accommodate around 80 percent or more of the inlets simultaneously.

So, yes, it’s real important to match ID or performance may suffer. It’s also important to have clean outs and traps designed into the system to prevent build-up.

What does Spencer have to say about the debris issue?

 

[mac]

Spencer says to just replace with more steel. Even they however used pvc going underground from the dirt canister to the vac turbines.