11
It is possible for a tank to become “water--logged” (filled with
water). It can also become overfilled with air. This can happen
after filling system with new water. Fittings are provided on tank
and in line to tank for bleeding off excess water or air.
When installing this tank, the following are important: :
1. Tank should be higher than boiler top.
2. Pipe to tank should continuously rise up to tank (so that
air can “bubble“ up through it).
C. Diaphragm--Type Expansion Tank (Not Provided)
The diaphragm--type expansion tank takes the place of a
conventional expansion tank. Read instructions packed with tank
assembly carefully. The tank comes with a 10--12 psi air charge.
This is the same as the pressure produced in system by automatic
fill valve. When system is first filled, ,tank contains little or no
water. .As water is heated, its pressure increases. It expands into
tank compressing the air in tank. This compressed air cushion
permits water in system m to expand as temperature changes. The
diaphragm--type expansion tank can be mounted on the air purger
fitting or at any other convenient place in the supply or return
line. It is recommended to locate the diaphragm type expansion
tank (a) in the supply line with the circulator located after the
expansion tank or (b) off the e3/4--in. tapping provided on the top
of the rear casting with the circulator mounted directly off the
boiler’s supply piping connection. This configuration allows the
circulator to “pump away” from the expansion tank for improved
air elimination and system performance. The air reliminator
fitting or air purger is not provided. The air eliminator fitting or
air purger is used to help remove air from the system before it
reaches the radiators. It should be installed in the supply line. Air
left in the system can cause noises in the pipes and inefficient
circulation in the radiators. .
D. Air Eliminating Fitting (Air Purger) (Not Provided)
Table 5 – Boiler Water Volumes
NUMBER OF BOILER SECTIONS
TOTAL VOLUME (GALLONS)
3
9.6
4
11.6
5
13.7
MUST BE REQUIRED MINIMUM
HEIGHT. MUST BE AT LEAST
3 FT HIGHER THAN HIGHEST
PART OF PASSAGE THROUGH
ROOF. MUST BE AT LEAST 2 FT
HIGHER THAN ANY NEIGHBORING
OBJECT. MUST HAVE AN
UNOBSTRUCTED TOP OPENING.
MUST BE AT LEAST
4 IN. THICK AND BE TIGHT.
BALANCED
WEIGHT
CRIMPED
END
ALTERNATE POSITIONS
TOP
TOP
MUST SLOPE UP AT
LEAST
1
/
4
IN. PER FOOT
OF HORIZONTAL RUN.
TIGHT CLEAN-OUT
DOOR
SEALED IN
THIMBLE
TIGHT, SMOOTH,
CORRECTLY SIZED.
DRAWBAND LAST
PIECE INSTALLED
DRAFT REGULATOR
VANE
A95601
Fig. 12 -- Typical Chimney Requirements
BW
4
/BW
5
