Part number 550-100-305/0916
37
AquaBalance
TM
W
ALL
M
OUNT
GAS
-
FIRED
WATER
BOILER
— C
OMBI
Boiler Manual
Figure 48
0IPINGTOCLOSEDTYPEEXPANSIONTANK
17
Primary/Secondary System Piping
(continued)
Closed-type expansion tank:
DO NOT use a closed-type tank if connecting to
a water heater that is equipped with an automatic
air vent.
Figure 48, shows suggested piping when using a closed-type
expansion tank, in which the air is directly in contact with
tank water.
Connect piping (½” or ¾”) from the air separator outlet to the
tank fitting. Slope any horizontal piping a minimum of 1 inch
per 5 feet of horizontal pipe.
Always use a
tank fitting
such as the B&G Tank-trol or Taco
Taco-trol (shown). The fitting reduces gravity flow of water in
the piping to the tank, avoids air bubbling through the tank
water, and provides the proper fill height in the tank.
Figure 47
0IPINGTODIAPHRAGMORBLADDER EXPANSIONTANK
C
orrect all leaks
in the system or tank piping. Leaks
allow air to escape from the system and will cause
water-logging of the tank. This will result in water
loss through the boiler relief valve due to over-
pressurization.
NEVER
use an automatic air vent
in a system equipped with a closed-type expansion
tank. The air removed from the system will cause
water-logging of the expansion tank.
Closed-type expansion tank—Follow tank manu-
facturer’s instructions for filling the tank. Typical
tank sizing provides for approximately 12 PSIG
when the tank is filled to the normal level and system
water is cold. Note that boiler relief valve is set for 30
PSIG. Operation pressure of system, after tempera-
ture expansion above cold fill pressure, should not
exceed 24 PSIG to avoid weeping of relieve valve.