DRAW
The draft of a chimney is determined by the following formula:
T = H (YA - YB)
T = Draft in mm.ca
H = Height of the vertical chimney in meters. YA =
Specific weight of the outside air in kg / m³.
YB = Specific weight of the combustion gases expelled in kg / m³.
SECTION
The section of the chimney for the two series is determined by the following formula:
S = 8.61 Q / H½
S = Section of the chimney in cm²
Q = This is the power of the boiler in kW / h. H =
The reduced height expressed in meters.
The reduced height of the chimney is defined by the following formula:
Hr = H - (N. 0.5 + L + R)
Hr = Reduced height
H = Actual height of the chimney. N
= Number of elbows.
L = Horizontal length.
R = Generator back pressure.
R = 1mm up to 50,000 kcal / h. R =
2mm up to 160,000 kcal / h.
NOTE: These values must be increased by 6% depending on the region for every 500
meters of elevation above sea level.
DUCT DEPRESSION
The draft measurement must be carried out under the shutter, which will allow the shutter to be
balanced during the measurement.
The flue gas pipe must never be reduced to a diameter smaller than that of the
outlet nozzle. However, there is no problem if the duct is of a larger diameter. In the
event of installation on an old masonry duct, it is essential to pipe the duct.
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02/04/2019
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During installation, at the time of commissioning, it is recommended to have a draft
measurement called "depression" carried out in order to check the water column of the
chimney's depression.
This measurement is carried out while hot when the device is at its normal output after
approximately half an hour of operation.
This depression should be 2 mm WC after the pull key.
It is therefore recommended for this result a vertical height of 5m for an
FH50ECP
and 6
to 7m for an
FH100ECP
.
In order to stabilize the draft, it is necessary to install at the outlet of the Ø 153mm nozzle for
FH50ECP
and 200mm for
FH100ECP
, a tee fitted with a regulator flap.
