Closed-Type Expansion Tank - Weil-McLain Series 2 Manual

® S
ERIES
Primary/Secondary System Piping

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 53 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 fi tting. Slope any horizontal piping a minimum of
1 inch per 5 feet of horizontal pipe.
Always use a tank fi tting such as the B&G Tank-trol or Taco
Taco-trol (shown). The fi tting reduces gravity fl ow of water
in the piping to the tank, avoids air bubbling through the
tank water, and provides the proper fi ll height in the tank
Correct 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
manufacturer's instructions for fi lling the tank.
Typical tank sizing provides for approximately
12 PSIG when the tank is fi lled to the normal
level and system water is cold. Note that boiler
relief valve is set for 30 PSIG. Operation pressure
of system, after temperature expansion above
cold fi ll pressure, should not exceed 24 PSIG to
avoid weeping of relieve valve.
48
2
-
G
AS FIRED WATER BOILER
— Boiler Manual
Figure 53 Piping to closed-type expansion tank
(continued)
Part number 550-142-190/1218