Raypak MVB 5042004 - Manual (Page 15)

15
Table F: Heater Rates of Flow and Pressure Drops
Note: Basis for minimum flow is ∆T. Basis for maximum flow is gpm.
Piping
All high points should be vented. A heater installed
above radiation level must be provided with a low wa-
ter cut-off device (sales order option F-10). This
heater, when used in connection with a refrigeration
system, must be installed so that the chilled medium is
piped in parallel with the heater with appropriate
valves to pre-vent the chilled medium from entering
the heater.
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. 11.
Fig. 11: Air-Separation/Expansion Tank
THERMOSTAT OR
SYSTEM SENSOR
Fig. 12: Single Heater - Low-Temperature (Heat Pump)
Application with Primary/Secondary Piping
THERMOSTAT OR
SYSTEM SENSOR
Fig. 13: Dual Heaters (Reverse/Return)
with Primary/Secondary Piping
Model
No.
Input Output 20° ∆T 30° ∆T 40° ∆T Min. Flow Max. Flow
MBTUH gpm ∆P gpm ∆P gpm ∆P gpm ∆P ∆T gpm ∆P ∆T
504 500 420 42 2.7 28 1.4 25 1.1 34 100 11.3 8
754 750 630 63 6.0 42 2.9 32 1.7 32 1.7 40 100 13.8 13
1104 1100 924 92 13.3 62 6.7 46 4.1 46 4.1 40 113 18.6 16
1504 1500 1260 84 13.3 63 8.0 63 8.0 40 113 22.2 22
2004 1999 1679 112 26.9 84 16.0 84 16.0 40 113 27.2 30
*Maximum 4 times the pipe diameter or 12”, whichever is less.
*Maximum 4 times the pipe diameter or 12”, whichever is less.