Wolf FGB-K Series Installation And Maintenance Instructions For Contractors page 46

Filling the heating system
To ensure correct function of the condensing boiler, fill
the system as instructed, vent it completely and fill the
trap.
We recommend using a sludge separator with integral
magnetite separator in the boiler inlet to protect the
high efficiency pump and the boiler. This is particularly
relevant for old systems and mixed installations.
Before connecting it, flush the entire system
Please note
to remove residues such as weld beads,
hemp, putty, etc. from the pipework. Check
the dirt filter.
• The gas condensing boiler must be switched OFF.
Close the gas ball valve.
• Open the cap of the automatic air vent valve on the
high efficiency pump by one revolution.
• Open all radiator valves.
Open the flow and return valves on the boiler.
• Slowly fill the entire heating system and gas
condensing boiler while cold up to approx. 2 bar via
the return line (external pressure gauge required).
Inhibitors and antifreeze are not permitted.
Please note
• Bleed all radiators and if the system pressure drops
significantly, top up with water to reach 2 bar again.
• Check the entire system and all component unions
for water leaks.
If leak tightness cannot be ensured, there is a
risk of water damage.
• Switch on the power supply to the gas condensing
boiler AP indication on the display for the duration of
the venting program.
• Briefly open the manual air vent valve on the flow
pipe until all air has escaped and then close it again.
Collect any water expelled.
46
18. Filling the heating system / trap
Fig: Automatic air vent valve on the heating circuit pump
Fig: Manual air vent valve
Automatic
air vent valve
Slightly open the
manual air vent valve
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