Vent Pipe Preparation, Initial Preparation

	TNR-I&S-02
Figure 21	Concentric Vent Side Wall Attachment

VENT PIPE PREPARATION

WARNING

DO NOT attempt to start this water heater until vent pipe solvent fumes completely clear from the room and inside the vent piping.

INITIAL PREPARATION

1.Make sure the solvent cement you are planning to use is designed for the specific application you are attempting.

2.Know the physical and chemical characteristics and limitations of the PVC, PVC cellular core or CPVC piping materials that you are about to use.

3.Know the reputation of your pipe and cement manufacturer and their products.

4.Know your own qualifications or those of your contractor. The solvent welding technique of joining PVC, PVC cellular core or CPVC pipe is a specialized skill just as any other pipe fitting technique.

5.Closely supervise the installation and inspect the finished job before start-up.

6.Contact the manufacturer, supplier, or competent consulting agency if you have any questions about the application or installation of PVC, PVC cellular core or CPVC pipe.

7.Take the time and effort to do a professional job. Shortcuts will only cause you problems and delays in start-up. The majority of failures in these systems are the result of shortcuts and/or improper joining techniques.

SELECTION OF MATERIALS

PRIMER – It is recommended that Tetrahydrofuran (THF) be used to prepare the surfaces of pipe and fittings for solvent welding. DO NOT use water, rags, gasoline or any other substitutes for cleaning PVC cellular core or CPVC surfaces. A chemical cleaner such as MEK may be used.

CEMENT – The cement should be a bodied cement of approximately 500 to 1600 centipoises viscosity containing 10-20% (by weight) virgin PVC material solvated with tetrahydrofuran (THF). Small quantities of dimethylformamide (DMF) may be included to act as a retarding agent to extend curing time. Select the proper cement; Schedule 40 cement should be used for Schedule 40 pipe. Never use all-purpose cements or commercial glues and adhesives to join PVC or CPVC pipe and fittings.

SAFETY PRECAUTION: PRIMERS AND CEMENTS ARE EXTREMELY FLAMMABLE AND MUST NOT BE STORED OR USED NEAR HEAT OR OPEN FLAME. ALSO, USE ONLY IN A WELL VENTILATED AREA.

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