15
Table F: Heater Rates of Flow and Pressure Drops
Notes: 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
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.
Applications & Modes
The VERSA IC Control system is designed for a wide
range of applications. The installer/design engineer
should refer to the following Modes to determine which
best fits the intended application and functionality for
the unit being installed.
Type H models of MVB have three modes available to
them to address the various applications the units can
be applied to. Type WH units will only have the WH
configuration available to them for use with potable
water applications when directly connected to a hot
water storage tank.
NOTE:
Hot water heating systems all have unique
levels of operating diversity that must be accounted
for in the system design. The system should always
include adequate system flow in excess of the
connected boiler flow for proper operation. Where
the system flow may drop below the connected
boiler flow a buffer/decoupler may be needed.
Failure to design for adequate flow (i.e. bypasses, 3
way control valves, flow limiting balance devices,
buffer tanks, etc.) will result in boiler short cycling
and may reduce boiler life. Always contact your local
Raypak representative for system design assistance
to avoid these issues.
GPM
P
GPM
P
GPM
P
GPM
P
T
GPM
P
T
503A
44
2.8
29
1.4
N/A
N/A
25
1.1
35
100
11.3
9
753A
65
6.4
44
3.1
33
1.9
33
1.9
39
100
13.8
13
1003A
87
12.0
58
6.0
45
3.8
45
3.8
39
113
18.6
15
1253A
109
20.9
73
10.2
56
6.5
56
6.5
39
113
22.2
19
1503A
N/A
N/A
87
16.0
67
10.0
67
10.0
39
113
25.5
23
1753A
N/A
N/A
102
22.5
78
14.0
78
14.0
39
113
27.2
27
2003A
N/A
N/A
116
31.9
89
19.8
89
19.8
39
116
32.0
30
Max Flow
MVB
Model
20° T
30° T
39° T
Min Flow
Содержание 503A
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