Roberts Gorden CRV-B-4 - Manual (Page 37)

SECTION 10: ROBERTS GORDON ® ULTRAVAC ™ D ESIGN R EQUIREMENTS
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SECTION 10: ROBERTS GORDON ® ULTRAVAC ™ DESIGN REQUIREMENTS
CRV-B-2 and CRV-B-4 are not available for use with
ROBERTS GORDON
® ULTRAVAC ™ controls.
CRV-Series systems designed with minimum
radiant tube lengthshall have 1.5' - 2.0' per flow unit of
tailpipe length.
-OR-
CRV-Series systems with recommended radiant tube
length shall have 1.2' - 1.5' per flow unit of tailpipe
length.