Raypak 504-2004 Water Heater User Manual


 
15
Table F: Heater Rates of Flow and Pressure Drops
Note: Basis for minimum flow is ΔT. Basis for maximum flow is gpm.
The piping system of a hot water heater connected to
heating coils located in air handling units where they
may be exposed to circulating refrigerated air, must be
equipped with flow control valves or other automatic
means to prevent gravity circulation of the heater
water during the cooling cycle. It is highly recommend-
ed that the piping be insulated.
Air-Separation/Expansion Tank
All heaters should be equipped with a properly sized
expansion tank and air separator fitting as shown in
Fig. 9.
Three-Way Valves
Three-way valves intended to regulate system water
temperatures by reducing flow in the boiler should not
be used. Raypak heaters are high-recovery, low-mass
heaters which are not subject to thermal shock. See
Fig. 14 and instructions on page 18 for adjusting the
manual bypass.
Fig. 9: Air-Separation/Expansion Tank