Rheem Power Direct Vent Series Use and Care Manual - Page 15

Maximum and Minimum Vent and Combustion Air-Inlet Lengths For Power Direct Vent Models: 50 Gallon With Inputs of 65,000 & 47,000 BTU/Hr. 65 Gallon With Inputs of 65,000 & 56,000 BTU/Hr. 75 Gallon With Inputs of 75,100 & 70,000 BTU/Hr. Connect the vent system piping to the blower assembly using the already installed 3 in. (7.6 cm) diameter rubber coupling and clamps. Connect the combustion air-inlet system piping to the combustion air-inlet piping tee using the 3 in. (7.6 cm) already installed rubber coupling and clamps (See Figure 3). For vent and combustion air-inlet terminals, use the two (2), 3 in. (7.6 cm) diameter, Schedule 40, PVC, 90°, 1/4 standard bend elbows and wire mesh screen assemblies supplied with the water heater. This water heater may also be installed with 4 in. (10.2 cm) diameter pipe and fittings for the vent and combustion air-inlet systems. When using 4 in. (10.2 cm) diameter pipe, two (2), 3 in. (7.6 cm) to 4 in. (10.1 cm) diameter pipe increaser fittings are required for connection of the vent system piping to the blower assembly and combustion air-inlet system piping to the combustion air-inlet piping tee couplings (See Figure 4). For vent and combustion air-inlet terminals, 4 in. (10.1 cm) diameter, Schedule 40, PVC, 90°, 1/4 standard bend elbows (not supplied) along with the two (2) wire mesh screens (supplied) must be installed. DO NOT use unequal sizes except as defined previously for the vent and combustion air-inlet systems. Combustion Vent Air-Inlet IMPORTANT: Ensure that all the coupling clamps are firmly tight, then leak test the vent system joints using a soap and water solution. Repair any leak before allowing the water heater to operate. When using CPVC or ABS pipe and fittings, use 90° elbows of the corresponding size and material for the vent and combustion air-inlet terminals. Install supplied wire mesh screens into the CPVC or ABS vent and combustion air-inlet terminal elbows. The vent and combustion air-inlet terminals of the water heater must be installed in the same atmospheric pressure zone. The minimum and maximum equivalent lengths for the vent and combustion air-inlet systems are shown in Table 2. Maintain a minimum vertical height of 1 foot (3.5 cm) of pipe from the blower exhaust before transitioning in any elbow. The vent and combustion air-inlet terminations are not included in the equivalency calculations. Notice: One (1), 90°, 1/4 standard bend elbow is equivalent to 5 feet (1.52 meters) of straight pipe and quantity one (1), 45°, 1/8 standard bend elbow is equivalent to 2.5 feet (0.76 meters) of straight pipe. DO NOT use short bend elbows. Vent 4 in. (10.2 cm) Combustion Air-Inlet 4 in. (10.2 cm) 3 in. (7.6 cm) 3 in. (7.6 cm) 3 in. (7.6 cm) 3 in. (7.6 cm) Figure 3 Figure 4 15