Roberts Gorden CRV-B-2 Tube Length vs. Efficiency, Design Parameters, 6.4CRV-SeriesDesign Methods

CRV-SERIES DESIGN MANUAL

FIGURE 16: Tube Length vs. Efficiency

Length of Tailpipe per Flow Unit (feet)

3.0

2.5

2.0

1.5

1.0

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83% 84% 85% 86% 87% 88% 89% 90%

Steady State Thermal Efficiency (%)

NOTE: Thermal efficiency values shown do not include the contribution due to condensing conditions when operating in cyclic fashion. To estimate cyclic efficiencies, add 2-3% to the values obtained from the graph.

6.3 Design Parameters

When designing branches of 4 B-8 or larger burners in-series, the following limitation to the pump capacity applies:

Pump Model Series Maximum Loading

EP-100:Not Allowed

EP-200:1 Branch of 4 burners

EP-300:2 Branches of 4 burners

For systems that are designed above 90% pump capacity, the following limitations of shared tailpipe apply:

•4" (10 cm) tailpipe: limited to maximum of 2 com- bined branches and length limited to maximum of 20' (6 m). See Page 14, Figure 15 for all other tailpipe considerations.

•6" (15 cm) tailpipe limited to maximum of 4 com- bined branches and length limited to maximum of 100' (30 m).

•When calculating required tailpipe length 1' (.3 m) of 6" manifold tube is equivalent to 1.3' (.4 m) of 4" tailpipe.

Failure to comply with the above parameters will result

in insufficient vacuum to burners.

6.4CRV-Series Design Methods

1.Layout the system to suit the BTU input required.

2.Calculate the system design for each branch individually.

3.Calculate the number of flow units per branch of burners. Add the flow units for each branch together to get the total system flow units. See Page 12, Table 1 for the rules for each burner model. See Page 13, Figure 14 for example flow unit calculations.

Flow Units Per Branch

Branch 1	+
Branch 2		+
Branch 3		+
Branch 4		+
Branch 5		+
Branch 6		+
Total System
Flow Units =

16