E93.1803.901 HW
32
8 THE HW SANITAIRY SYSTEM: INSTALLATION INSTRUCTIONS
The HW system
The CB-HW boilers are designed for use with one or more hot water tanks, because the boiler needs a minimum
amount of water flow. To get an output temperature of 60°C, the temperature of the return should be within the
range 43.5
– 47.5 °C.
In designing the hot water system there are some points to consider:
-
How many boilers and how many tanks are needed to accommodate the desired domestic hot water flow.
- Water hardness: a high water hardness will lead to calcification of the heat exchanger, especially when
water temperatures are high. Calcification can be delayed by increasing the waterflow through the boiler
resulting in a smaller temperature difference between in- and output of the boiler:
•
If the water hardness is between 4 and 11 °dH the temperature difference between flow and
return of the boiler should be 16.5 °C maximum
•
If the water hardness is between 11 and 14 °dH the temperature difference between flow and
return should be 12.5 °C maximum
•
If the water hardness is above 14 °dH a water softener should be considered. Also above 11 °dH
a water softener could be considered, since an installation at 12.5 °C temperature difference will
need bigger pipes and pumps. After softening, the water hardness should be minimum 4 °dH
- Pipework is to be made of copper or stainless steel pipes, diameters according or bigger than prescribed
below. When using plastic pipes, make sure the inner diameter of the pipes is at least equal to the corre-
sponding copper size.
8.1.1
S
TAND
-
ALONE SET
-
UP
The basic form of a HW installation is one water heater with one tank.
CB-85-HW
CB-105-HW
CB-125-HW
CB-155-HW
Boiler flow at ΔT = 16.5 °C (m
3
/h)
4.26
5.07
6.22
7.57
Pipework size at ΔT = 16.5 °C
42 x 1.5
42 x 1.5
42 x 1.5
54 x 1.5
Maximum pipe length (m) *
2 x 20
2 x 15
2 x 30
2 x 30
Pump advice at ΔT = 16.5 °C
1*
1*
2*
2*
Boiler flow at ΔT = 12.5 °C (m
3
/h)
5.62
6.69
8.21
10.0
Pipework size at ΔT = 12.5 °C
42 x 1.5
54 x 1.5
54 x 1.5
54 x 1.5
Maximum pipe length (m) *
2 x 14
2 x 18
2 x 30
2 x 30
Pump advice at ΔT = 12.5 °C
2*
2*
X
1)
X
1)
Table 1: Pipe sizes and pumps
*(see table 3)
1)
NB!
An X in the pump table doesn’t necessarily mean that the corresponding installation cannot be built. If it
can, it will need specific design effort and pump selection. Please consult your supplier for advice.
•
Adding bends or valves to the pipe system influences water resistance and maximum pipe length. In the table
below equivalent pipe lengths are given, which should be subtracted from the given maximum pipe length.
Table 2: Equivalent pipe lengths
Pump number
Pump type
1
Grundfos UPMXL GEO 25-125N 180
2
Wilo Stratos Para Z 25/1-12
Table 3: Pump types
Copper
pipe
diameter D
Equivalent pipe length
90° bend
R = 1
D
Equivalent pipe length
45° bend
R = 1
D
Equivalent pipe length
valve
mm
mm
M
m
m
42
1.5
0.5
0.3
0.1
54
1.5
0.8
0.3
0.2
Summary of Contents for CB 105 HW
Page 69: ...E93 1803 901 HW 70 12 6 Electrical schematic...
Page 70: ...E93 1803 901 HW 71...
Page 71: ...E93 1803 901 HW 72 12 7 Ladder Logic Diagram LOW MAINS VOLTAGE VOLTAGE...
Page 127: ...E93 1803 901 HW 128 22 SPARE PARTS CB 85 HW CB 105 HW and CB 125 HW exploded view...
Page 128: ...E93 1803 901 HW 129...
Page 129: ...E93 1803 901 HW 130 CB 155 HW exploded view...
Page 130: ...E93 1803 901 HW 131...
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