1.8.4 BOILER ROOM PRESSURIZATION
The boiler room must be supplied with adequate air
for combustion and for proper operation of draft
control devices (barometric dampers or draft
diverters) as outlined in "Combustion Air Supply",
Section 1.7 of this manual.
WARNING
THE BOILER ROOM MUST BE MAINTAINED AT A
POSITIVE OR NEUTRAL PRESSURE (RELATIVE
TO OUTDOORS) AT ALL TIMES. EXHAUST FANS
OR CONNECTIONS FROM THE BOILER ROOM
TO ZONES OF NEGATIVE PRESSURE (AIR
DUCTS, NEGATIVE PRESSURE ROOMS, ETC.)
WILL CAUSE NEGATIVE PRESSURE IN THE
BOILER ROOM. SUCH CONDITIONS WILL CAUSE
HAZARDOUS OPERATION OF THE BOILER AND
INTRODUCTION OF COMBUSTION PRODUCTS
INTO THE BUILDING AIR.
AND A DRAFT PROVING SWITCH MUST BE
INSTALLED TO PREVENT OPERATION OF THE
BOILER IF THE FAN SHOULD FAIL TO OPERATE.
IT ALSO MAY BE ADVISABLE TO INSTALL AN
AUTOMATIC VENT DAMPER IN THE VENT
SYSTEM TO PREVENT BACKFLOW THROUGH
THE VENT SYSTEM DURING BOILER OFF
CYCLES. SEE FOLLOWING SECTION ON
AUTOMATIC VENT DAMPERS.
IF THE BOILER ROOM MUST BE UNDER A
NEGATIVE PRESSURE AT ANY TIME, AN
INDUCED DRAFT FAN WILL BE REQUIRED.
FURTHER, THE BOILER MUST BE PROVIDED
WITH A "SINGLE ACTING" BAROMETRIC DRAFT
CONTROL - NOT WITH A DRAFT DIVERTER. THE
FAN MUST BE INTERLOCKED WITH THE BOILER
1.8.5 DRAFT CONTROL INSTALLATION - DRAFT DIVERTER
Each atmospheric gas boiler is supplied with a
VERTICAL DRAFT DIVERTER or a BAROMETRIC
DRAFT REGULATOR. THESE DEVICES MUST BE
INSTALLED WITHOUT MODIFICATION. DO NOT
SHORTEN THE COLLAR LENGTH OF A DRAFT
DIVERTER. INSTALL THE BAROMETRIC
DAMPER (IF SUPPLIED) PER INSTRUCTIONS IN
SECTION 1.8.6.
Refer to boiler dimensional for the required distance
from the top of the DRAFT DIVERTER (when
supplied) to the floor. The flue pipe (straight section)
of the diverter must not be shortened or modified in
any manner. The draft diverter must be mounted
directly on top of the boiler as shown in Fig. 1.8.1A.
1.8.6 DRAFT CONTROL INSTALLATION - BAROMETRIC D. R.
FIG. 1.8.6A: BAROMETRIC DRAFT CONTROL
LOCATIONS
FIG. 1.8.6B: BAROMETRIC CONTROL - MG2
BAROMETRIC DRAFT REGULATORS (when supplied)
must be installed such that the minimum distance from
the centerline of the barometric draft control to the top of
the boiler jacket is at least one flue pipe diameter.
Barometric draft controls should preferably be mounted
in the end of a tee as shown in Fig. 1.8.6A. This will allow
better control of minor downdraft conditions.
Содержание AB Series
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