2015 Maxitrol Company. All Rights Reserved. DRAFT 09.18.2013 58 When sizing a regulator the following must be known Gas Type Available Inlet Pressure Desired Outlet Pressure Zero Governor Application indicated by model number ending in Z Will the regulator control main burner and pilot load OR main burner only Required minimum and maximum flow rate in cfh or m3 h or Btuh Pipe Size In most cases the manifold pipe size has already been selected on the basis of good engineering practice and the regulator pipe size should conform to this size. The capacity of any regulator is not an absolute value but will vary with the application depending on the prevailing differential pressure. Service and installation must be performed by a trainedexperienced service technician. All products used with combustible gas must be installed and used strictly in accordance with the instructions of the Original Equipment Manufacturer OEM and with all applicable government codes and regulations e.g. plumbing mechanical and electrical codes and practices. These instructions do NOT supersede OEMs installation or operating instructions. All Maxitrol products should be installed and operated in accordance with Maxitrol Safety Warning Instructions. HOW TO CALCULATE PRESSURE DROP AT VARIOUS FLOW RATES FROM CAPACITY CHART LP Applications - When using natural gas pressure drop chart to determine LP pressure drop in terms of Btuh multiply LP Btuh by 0.621 in terms of CFH multiply LP CFH by 1.55. Formula P2 P1 x Q2Q12 P2 Pressure drop at desired flow rate Q2 Desired flow rate P1 Known pressure drop Q1 Known flow rate A. Check Capacity Chart insuring regulator has ample range B. Know the minimum encountered inlet pressure. of regulation and individual load capacities for use with pilot MINIMUM INLET PRESSURE MINUS P2 MUST for the application. BE GREATER THAN DESIRED OUTLET PRESSURE. Solve for P2 using the formula above. See examples on page 59. SIZING A REGULATOR System Requirements See www.maxitrol.com for our Regulator Sizing Program. Please contact Maxitrol directly for more information on sizing a regulator.