96
13
STARTING THE BOILER
13.1
General
Check the gas pressure available at the gas connection pipe of the boiler. Use the pressure nipple (4)* of the gas
safety valve for this measurement. The gas input pressure for the boiler, to operate properly under the correct load,
must be at least 20 mbar at high fire.
* Gas valve screws and nipples: see picture on page 101.
The boiler has two identical gas control valves: one for the top burner (MASTER) and one for the bottom burner
(SLAVE 1). Both gas valves must be adjusted at maximum load and at minimum load.
Two burners are present in one heat exchanger. In fact, into one stainless steel casing, two heat exchangers have
been built, a primary and a secondary. The primary exchanger, moreover, consists of an upper and a lower part. The
upper part in which the top burner fires, is only transferring heat from the top burner. The lower part in which the
bottom burner fires, is only transferring heat from the bottom burner. After the flue gases have passed the primary
heat exchanger, they merge in the central part. In this secondary part, the remaining heat is extracted from the flue
gases of both burners, causing condensation of the gases, if cooled down sufficiently.
Measuring the CO
2
percentage in the flue gas outlet outside the boiler, while both burners are burning, will result in
an average CO
2
value. It is possible that this average value is correct, while the CO
2
setting of the top burner is too
low and the CO
2
setting of the bottom burner is too high. Therefore, the CO
2
levels of each burner must be adjusted
separately. Measurements are performed at the front, by making use of two measuring holes. See drawing.
Top (primary) heat exchanger
Top burner
Plug for top measuring hole
Top measuring hole for
flue gas measuring
(Secundary heat exchanger)
Bottom measuring hole for
flue gas measuring
Plug for bottom measuring hole
Bottom burner
Bottom (primary) heat exchanger
