37
GAS FEED SYSTEM AT LOW PRESSURE (max. 400 mm.W.C.)
When the burner has been correctly fastened to the boiler,
proceed with connecting it to the gas pipeline (see BT 8780
and BT 1387).
The dimension of the gas adduction pipeline should be in
proportion to its length and to gas delivery and the load
loss should not exceed 5 mm.W.C. (see diagram).
It must also be perfectly hermetic and adequately tested
before the burner’s general inspection. It is indispensable
to install a proper fitting on the pipeline, in proximity to the
burner, to allow for easy disassembling of the burner and/
or opening of the boiler door.
In addition, the following should be installed: a cut-off cock,
a gas filter, a stabilizer or a pressure regulator (when the
feed pressure is superior to 400 mm.W.C. = 0,04 bar), and
an antivibration joint. These parts should be installed as
described in our drawing (see BT 8780 ).
We consider it useful to give the following practical tips for
installing the essential accessories on the gas pipeline near
to the burner:
1)
To avoid big drops in pressure on ignition, the
length of the pipeline between the
point where the stabilizer or reducer is fitted and
the burner should be from 1,5 to 2 m. This pipe
must have a diameter equal or superior to that of
the burner attachment fitting.
2)
The gas fitting must be applied on horizontal
pipes.
This is to avoid any impurities falling into the pipes
or entering the stabilizer during cleaning.
3)
To get the best performance out of the pressure
stabilizer, it is advisable to fit it onto
horizontal pipes, after the filter.
In this way, the vertical movement of the entire mo-
bile part (shutter) of the stabilizer is rapid. (If the
movement of the mobile part were horizontal - with
the stabilizer fitted onto vertical pipes - friction to
the guide bush/es of the pin to which the entire
mobile part is fitted would delay movement).
4)
We advise installing a bend directly onto the
burner gas ramp before applying the
removable fitting.
This layout makes it possible to open the boiler
door, if there is one, after the pipe fitting itself has
been opened.
The above information is clearly illustrated in drawing BT
8780.
GENERAL DIAGRAM FOR INSTALLATION OF GATE-FILTER-
STABILIZER-ANTI-VIBRATION JOINT-OPENABLE PITTING
8780GB.tif
8871GB.tif
