Crown Boiler PHNTM080 - Piping for Special Situations

75
D. Piping for Special Situations
1) Systems containing oxygen - Many hydronic systems contain enough dissolved oxygen to cause severe corrosion
damage to a this boiler. Some examples include:
  •Radiantsystemsthatemploytubingwithoutanoxygenbarrier.
  •Systemswithroutineadditionsoffreshwater.
  •Systemswhichareopentotheatmosphere.
If the boiler is to be used in such a system, it must be separated from the oxygenated water being heated with a heat
exchanger as shown in Figure 9.10. Consult the heat exchanger manufacturer for proper heat exchanger sizing as well as
owandtemperaturerequirements.Allcomponentsontheoxygenatedsideoftheheatexchanger,suchasthepumpand
expansion tank, must be designed for use in oxygenated water.
2) Piping with a Chiller - If the boiler is used in conjunction with a chiller, pipe the boiler and chiller in parallel. Use
isolation valves to prevent chilled water from entering the boiler.
3) Air Handlers-Wheretheboilerisconnectedtoairhandlersthroughwhichrefrigeratedairpasses,useowcontrol 
valves in the boiler piping or other automatic means to prevent gravity circulation during the cooling cycle.
FIGURE 9.10: ISOLATION OF THE BOILER FROM OXYGENATED WATER WITH A PLATE HEAT EXCHANGER