Installation and operating instruction
Oil condensing boiler WTC-OB 18-B
5 Installation
83311002 1/2018-03 La
23-132
5.1.2 Fill water quantity
If information about the fill water quantity is not available, the following table can be
used to estimate the quantity.
For systems with buffer vessels, the buffer content must be taken into account.
Heating system
Estimated fill water quantity
(1
55/45 °C
70/55 °C
Pipe and steel radiators
37 l/kW
23 l/kW
Cast iron radiators
28 l/kW
18 l/kW
Panel radiators
15 l/kW
10 l/kW
Air conditioning
12 l/kW
8 l/kW
Convectors
10 l/kW
6 l/kW
Underfloor heating
25 l/kW
25 l/kW
(1
based on the heating requirements of the building.
5.1.3 Treat the fill and top-up water
De-ionisation (recommended by Weishaupt)
De-ionise the fill and top-up water completely.
(Recommendation: mixed bed procedure)
When the heating water has been entirely de-ionised, additional top-up water up to
10 % of the system contents may be untreated. Higher quantities of top-up water
must be de-ionised.
Check the pH value (8.5 ±0.5) of the de-ionised water:
after the commissioning,
after approx. 4 weeks of operation,
during the annual servicing.
If necessary, increase thepH value of the heating water by the addition of Triso-
dium Phosphate.
Softening (cation exchanger)
CAUTION
Damage to the appliance due to raised pH value
Softening the water by means of cation exchange leads to self alkalisation of the
heating water. Corrosion can damage the appliance.
Following the softening of the water by means of cation exchanger the pH value
has to be stabilised.
Soften the fill and top-up water.
Stabilise the pH value.
Check pH value of (8.5 ±0.5) during the annual servicing.
Stabilisation of hardness
CAUTION
Damage to the appliance due to inappropriate inhibitors
Corrosion and scale could damage the appliance.
Only use inhibitors when the manufacturer can guarantee the following:
the requirements relating to the heating water are fulfilled,
the heat exchanger in the appliance will not be attacked by corrosion,
there will be no formation of sludge in the heating system.
Treat the fill and top-up water with inhibitors.
Check the pH value (8.5 ± 0.5) according to the instructions provided by the
manufacturer of the inhibitors.
