FireBird HEAT PAC 120/150, Installation Servicing & Operating Instructions, Page: 37 / 56

SYSTEM FILLING, TESTING AND MAKE-UP
Heating Circuit
This is the Radiator Heating System including boiler which is filled from mains supply via flex filling
loop Part No. 4 (Page 38) within boiler to a pressure determined from system static head,
expansion vessel size and system water volume.This flexible filling loop should be disconnected
when boiler and system are filled and checked, See diagrams below.
35
System filling should take place slowly and can be done by either of the following methods:-
Manual Filling
Fill system through drain tap made up on central heating system.
Automatic Filling
Automatic System filling may be made with a feed and make-up cistern connected through a double check
valve and stop valve assembly to the return side of the heating system as close to the boiler as is practicable.
This cistern
should be located above the heating systems highest point to give a minimum static head of
300 mm between it (highest point) and cistern. The manual filling system fitted to boiler should then be
disconnected and connection points blanked off.
This system has the advantage of automatic water make-up in the event of system pressure loss due to air
elimination and minor leaks. In any case control panel pressure gauge should be occasionally checked.
Remember also to check air fill pressure of Expansion Vessel when system is cold using
standard tyre gauge connected to Schrader air valve on vessel.
NOTE: There shall be no direct connection to the mains, even with the use of
a non-return valve without the permission of Local Water Authority.
* It is recommended that an inhibitor be added at the time of final fill to
protect the System from corrosion. Ensure that this is carried out in
accordance with inhibitor manufacturers instructions. Installer should
ensure that inhibitor used is suitable and that it will have no adverse effect
on Expansion Vessels diaphragms or any other part or component of the
system.
Method A
Method B