Buderus Logano plus GB312 Applications Manual page 13

GB312 Applications Manual
3.3 Water hardness
Use only clean municipal water to fi ll the system.
In order to protect the appliance against limescale damage
over its entire service life and in order to ensure trouble-free
operation, the total amount of limescale-forming substances
in the fi rst-fi ll and replenishment water
used in the heating system must be limited.
3.4 Checking the maximum quantity of fi rst-fi ll
water based on water quality
USER NOTE
If the system capacity exceeds the calcu-
lated allowable water volume V
damage to the boiler can result.
To check the permissible water quantities based on water
quality, either use the following calculation methods or
consult the graphs.
Calculation basis
The fi rst-fi ll and replenishment water has to meet certain
requirements that are dependent on the total boiler output
and the resulting total volume of water in the heating sys-
tem. Use the following formula to calculate the maximum
quantity of fi ll water that may be introduced without
treatment:
3
V (ft )= 0.0243
max
Formula for calculating the maximum quantity of
(untreated) water that may be introduced
Vmax = maximum volume of untreated fi rst-fi ll and
replenishment water in ft³ that may
be introduced into the system over the
entire service life of the boiler
(1ft³ = 7.48 gallon)
Q
Out = Total boiler output in Btu/h (see Tab. 1)
CaCO3 = Calcium carbonate concentration (hardness) in
ppm (1ppm = 1mg/l)
Information about the calcium carbonate (CaCO3, hard-
ness) concentration of the municipal water can be obtained
from your local water company.
Logano plus GB312 applications manual | 04.2008
,
max
× Q
(Btu/h)
Out
CaCO (ppm)
3
Example calculation:
Calculation of the maximum permitted quantity of fi rst-fi ll
and replenishment water, Vmax, for a heating system with a
total boiler output of 955,400 Btu/h (boiler size 280–8).
Water hardness analysis fi gures quoted in ppm (CaCO3).
Q
Out = 955,400 Btu/h
Hardness (CaC03) = 280 ppm
Maximum permissible water volume Vmax
955,400 Btu/h
x
V = 0.0243
max
280 ppm
Boiler size
90-4
120-4
160-5
200-6
240-7
280-8
Tab. 5 Boiler output
3.5 pH requirements
• The optimal range of pH for the boiler system fluid is 7.0
to 8.5.
• pH must be checked and recorded at each yearly
maintenace in order to keep the warranty valid.
• Failure to do so will immediately void the warranty on the
heat exchanger
• Adjusting pH if it is out of range (7.0pH to 8.5pH)
- Flush system with fresh municipal water, run the
system up to temperature for an hour and check pH.
OR
- Add Rhomar Protek 922 to the system at a volume of 1
gallon of Protek 922 to 25 gallons of system volume.
Technical specifi cations are subject to change without prior notice
| 13
3
= 83 ft
Boiler output Q [Btu/h]
out
122/86°F
307,090
409,460
545,940
682,430
818,910
955,400