TABLE OF CONTENTS
4.1.
4.2.
Pressure Relief Valve .................................................................................................................... 15
4.3.
Boiler Air Vent ................................................................................................................................ 16
4.4.
Low Water Cutoff Device .............................................................................................................. 16
4.5.
Additional Limit Control ................................................................................................................ 17
4.6.
Backflow Preventer ....................................................................................................................... 17
4.7.
4.7.1
4.7.2
Diaphragm Expansion Tank ................................................................................................ 18
4.7.3
4.7.4
Circulator .............................................................................................................................. 19
4.7.5
Sizing Primary Piping .......................................................................................................... 19
4.7.6
4.7.7
4.7.8
4.7.9
4.8.
4.8.1
4.8.3 Circulator ..............................................................................................................................22
4.8.4 Sizing Primary Piping ..........................................................................................................23
4.9.
iv