Measuring: Measurements should be taken from the
base of the pipe-stop, which is on the inside of the fit-
ting hub. As each section of tubing is cut, it should be
dry fitted before the next measurement is taken.
Cutting: The tubing must be cut as straight and square
as possible. A miter box should be used if available. All
rough edges must be removed with a utility knife or
coarse sandpaper.
Dry Fitting: Once all the pieces are cut, they should be
dry fitted to check for correct fit. The markings on the
fittings can be utilized to assure proper alignment.
Gluing: PVC solvent cement actually welds the fitting to
the tubing. A chemical reaction permanently joins the
molecules from each surface to produce an airtight seal.
Before cementing, both the tubing and the fitting must
be free of PVC burrs, dirt, and grime. The components
should be wiped with a clean cloth if necessary. Cement
should only be applied to the tubing because cement
applied to the fitting will be pushed ahead and create a
rough bead on the inside of the fitting. This bead will
reduce airflow and could cause a clog. The tubing
should be inserted all the way into the fitting and
twisted a quarter turn to evenly distribute the cement.
All excess cement should be removed with a rag. The
glue should be allowed to set for several hours before
the vacuum system is used.
Every power unit has an on/off switch that is activated
by completing a circuit at the inlet valves. The power
unit is turned on by simply inserting the hose in the
inlet valve. To facilitate this, low voltage wire must fol-
low the tubing system. At the junction of a branch line
and the trunk line, the wires must be spliced together.
Each inlet valve must be able to activate the machine
independently of the other valves. There must be an
uninterrupted route from each inlet valve to the power
unit. With wire ties, attach the wire to the tubing at
least every four feet. If using Lexan inlet valves, do not
loop wires at valve locations. Only one pair of wires
can be hooked up to these valves.
HOW TO CUT AND CEMENT PVC TUBING AND FITTINGS
LOW VOLTAGE WIRE
PAGE 4
Planning the Central Vacuum System (Continued)
