LAARS U.H.E. - Installation Manual - Manual (Page 33)

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, ABS 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, ABS 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, ABS 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, ABS 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, commercial glues and adhesives or ABS cement
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.
SECTION VII: GAS CONNECTIONS
WARNING
Connect this water heater only to the type of gas as shown on the rating plate. Use clean black iron pipe or
equivalent material approved by local codes and ordinances. (Dirt and scale from the pipe can enter the gas valve
and cause it to malfunction). The inlet gas line must have at least a 3 inch (7.62 cm) drip leg (sediment trap)
installed as close to the water heater’s gas valve as possible. A ground joint union must be installed in the gas
supply line, as close to the water heater as possible, to permit servicing of the water heater. Compounds used on the
threaded joints of the gas piping must be resistant to the action of liquefied petroleum gases/propane gas. DO NOT
apply pipe dope to the gas valve inlet and make certain that no pipe dope has become lodged in the inlet screen of
the gas valve. Extreme care must be taken to ensure no pipe dope enters the gas valve and to avoid excessive torque
when tightening the gas supply line to the gas valve. Excessive torque may result in cracking of the gas valve
housing. The suggested maximum torque is 31.5 foot lbs. (4.4 kg-m). The manufacturer of this water heater will
not be liable for any damage or injury caused as a result of a cracked gas inlet as a result of excessive torque.
This water heater and its gas connection must be leak tested before placing the water heater in operation. Check for
gas leaks with a soap and water solution and a brush or a commercial leak detector fluid.
NEVER USE A MATCH OR OPEN FLAME FOR TESTING!
The water heater is not intended for operation at higher than 14.0 inch water column (½ psi) supply gas pressure.
Higher gas supply pressures require supplemental reducing service regulation. Exposure to higher gas supply
pressure may cause damage to the gas controls, which could result in fire or explosion. If overpressure has occurred
such as through improper testing of gas lines or emergency malfunction of the supply system, the gas valve must be
checked for safe operation. Make sure that the outside vents on the supply regulators and the safety vent valves are
protected against blockage. These are parts of the gas supply system, not the water heater.
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