Reznor RHC 8000 DJL, Application Instructions

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0710RHC8-JLNLEN 23 / 36
11.0 H
EATING SECTION WITH BY
-
PASS
CHANNEL
11.1 By-pass requirements
11.1.1
Referring to section 4.1.3, a by-pass duct in
parallel with the heat exchanger enclosure
might be required.
11.1.2
Such by-pass duct might also be required to
reduce the pressure loss over the heating
section, particularly at higher air flows.
11.1.3
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.
11.1.4
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 7
Table 7
Model V1
(m ³ )
V2
(m ³ )
8030 06 3750 4400
8045 09 5650 6600
8050 06 6200 7150
8060 12 7500 8750
8075 09 9300 10790
8075 15 9300 11900
8090 18 11200 14300
8100 12 12400 14300
8125M.15 15600 18000
8150M.18 18200 21000
8175M.21 20100 21500
8200M.24 23300 24000
V1 = min. airflow required through heat
exchanger enclosure
V2 = minimum airflow required without
perforated inlet plate
11.2 Calculation of recommended maximum by-
pass (not applicable for 8000M models)
11.2.1
This calculation is applicable for total airflow
conditions above V2 (table 7).
11.2.2
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.
A) 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).
a) By-pass besides heat exchanger :
Model dim. B (mm) factor R1 factor R2
8030 06 461
295.
00
-350.
60
8045 09
671
196.
80
-354.
10
8050 06 461
272.
30
-532.
80
8060 12 880
146.
30
-346.
00
8075 09 671
174.
40
-514.
10
8075 15
1090
112.
50
-357.
50
8090 18 1299
93.
00
-362.
40
8100 12 880
129.
90
-508.
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
117.
70
-141.
30
8045 09 1170
112.
00
-200.
00
8050 06
1770
70.
90
-138.
80
8060 12 1170
111.
10
-265.
10
8075 09 1770
66.
10
-194.
90
8075 15 1170
105.
80
-345.
70
8090 18
1170
104.
80
-412.
70
8100 12 1770
64.
60
-252.
70
4
Dimension A (mm) = R1 x V
tot
+
R2
B) Example :
RHC 8075 09 RJL
with :
- total air flow = 5.0m³/s = 18000 m³/h
- by-pass besides heat exchanger
Result :
- dimension B = 670. 50 mm
- dimension X = 400mm (see fig. 13)
- R1 = 174. 40
- R2 = -514. 10
- dimension C = 174. 40 .5 x 5. 00 – 514. 10
4
C = 357. 90 mm