Practical Information For Heating Contractors - Baxi POWER HT-A 1.430 Installation Manual

Prior to installation
4.14 Practical information for
heating contractors
3 8
1. With reference to the specific system volume (e. g. when using heating water
buffer cylinders), determine which requirements apply regarding total hard-
ness of the fill and top-up water to VDI Directive 2035 and the the following
table.
If partial softening to 6 °dH is insufficient according to the project-specific wa-
ter hardness diagram, use either an additive or use only fully desalinated water
(with pH stabiliser).
If a boiler is replaced in an existing system, we recommend installing a dirt trap
or filter in the system return, upstream of the boiler. Flush the system thor-
oughly.
2. Depending on the materials used, determine whether the addition of inhibi-
tors, partial softening or full desalination is the best method.
3. Record the filling process (if possible, use the BAXI system log. If an additive
is used, note this on the boiler). To prevent gas pockets and bubbles, it is essen-
tial to fully vent the system at maximum operating temperature.
4. After 8 to 12 weeks, check and record the pH value. Offer and conclude a main-
tenance contract.
5. Once a year, check the system is operating correctly with regard to pressure
maintenance, pH value and the volume of top-up water used.
Tab. 4: Table to VDI 2035 Sheet 1
Total heating output
in kW
*)
< 50
50 - 200
200 - 600
> 6 0 0
*) for system boilers (< 0.3 l/kW) and systems with electric heating elements
Total hardness in °dH
subject to the specific system volume
< 2 l 0 k / W 2 l 0 k / W a
16.8 11.2
11.2 8.4
8.4 0.11
0 1 . 1 <
n d < 5 l 0 k / W 5 l 0 k /
< 0.11
< 0.11
< 0.11
0 1 . 1 < 0 1 . 1
W