Reznor RHC 8000 DJL, Application Instructions

Page: 32 / 36

0710RHC8-JLNLEN 32 / 36
12.4 Multiple heating sections in series with by-pass channels
(not applicable for RHC 8000M models)
12.4.1 By-pass requirements :
* Referring to section 4.1.3, a by-pass duct
in parallel with the heat exchanger
enclosure might be required.
* Such by-pass duct might also be required
to reduce the pressure loss over the
heating section, particularly at higher
airflows.
* When a by-pass duct is applied, a portion
of the total airflow is guided through the
by-pass duct and the remaining airflow is
guided through the heat exchanger
enclosure.
* The by-pass duct dimensions must be
properly determined in order to ensure that
the airflow through the heat exchanger
enclosure always meets the minimum
airflow requirements as mentioned in table
8.
12.4.2 Calculation of recommended maximum by-
pass :
* This calculation is applicable for total
airflow conditions above V2 (table 8).
* Consequently, the perforated inlet plate
must NOT be installed and must not be
applied in combination with the by-pass as
determined by the calculation method
underneath.
The by-pass can either be mounted on top of
the heat exchanger or besides the heat
exchanger as shown in figure 13.
The recommended maximum by-pass
dimensions for a given air flow (V
tot
) can be
calculated as follows : (V
tot
is the air flow
expressed in m³/s).
F
OR
2
UNITS IN SERIES
a
)
By-pass besides heat exchanger :
Model dim. B (mm) factor R1 factor R2
8030 06
461
255.
50
-268.
00
8045 09 671
150.
40
-270.
70
8050 06 461
199.
10
-383.
50
8060 12 880
111.
90
-264.
70
8075 09
671
126.
60
-386.
20
8075 15 1090
85.
60
-276.
70
8090 18 1299
72.
70
-285.
50
8100 12 880
97.
20
-377.
00
4
Dimension C (mm) = R1 x V
tot
+ R2
b) By-pass on top of heat exchanger :
Model dim. D (mm) factor R1 factor R2
8030 06 1170
90.
00
-108.
10
8045 09 1170
85.
60
-152.
90
8050 06
1770
51.
90
-202.
50
8060 12 1170
84.
90
-99.
90
8075 09 1770
48.
00
-138.
80
8075 15 1170
79.
70
-267.
70
8090 18
1170
80.
70
-316.
90
8100 12 1770
48.
80
-190.
90
4
Dimension A (mm) = R1 x V
tot
+
R2
F
OR
3
UNITS IN SERIES
a) By-pass besides heat exchanger :
Model dim. B (mm) factor R1 factor R2
8030 06
461
200.
50
-288.
10
8045 09 671
109.
80
-236.
40
8050 06 461
145.
10
-348.
10
8060 12 880
81.
50
-234.
50
8075 09
671
92.
30
-399.
00
8075 15 1090
67.
40
-285.
50
8090 18 1299
56.
70
-246.
80
8100 12 880
72.
60
-338.
90
4
Dimension C (mm) = R1 x V
tot
+ R2
b) By-pass on top of heat exchanger :
Model dim. D (mm) factor R1 factor R2
8030 06 1170
79.
20
-114.
00
8045 09 1170
76.
50
-164.
70
8050 06 1770
38.
30
-92.
20
8060 12
1170
74.
40
-214.
30
8075 09 1770
35.
40
-125.
70
8075 15 1170
63.
30
-225.
60
8090 18 1170
62.
90
-274.
10
8100 12
1770
36.
10
-168.
50
4
Dimension A (mm) = R1 x V
tot
+
R2