Trane Climate Changer T Series Installation Operation & Maintenance page 53

CAUTION
Vacuum Breaker Cracking Pressure!
The 1/2-inch NPT, 15 degree swing check valve vacuum breaker is recommended
because other vacuum breakers, such as spring-loaded ball-check breakers, have
cracking pressures as high as 1.25 inches Hg (17 inches of water). Vacuum breakers
with fitting sizes smaller than 1/2 inch NPT are too small to relieve vacuum quick
enough to ensure complete condensate drainage. Other types of swing check valve
vacuum breakers are acceptable if the fittings size is not smaller than 1/2-inch NPT and
the cracking pressure is not larger than 0.25 inches Hg (3.4 inches of water). Failure to
follow these instructions may result in equipment damage.
To prevent coil damage, complete the following recommendations:
•
•
•
Note: Vacuum breaker relief is mandatory when the coil is controlled by a modulating
CLCH-SVX06A-EN • T-Series Climate Changer Air Handler IOM
Install a 1/2-inch NPT, 15 degree swing check valve vacuum breaker with cracking
pressure of 0.25 inches Hg (3.4 inches water) or lower at the top of the coil. This
vacuum breaker should be installed as close to the coil as possible.
Types T and ST coils require that the vacuum breaker be located as near as possible
to the supply connection.
Vent the vacuum breaker line to atmosphere or connect it into the return main at the
discharge side of the steam trap
steam supply or automatic two position (ON-OFF) steam supply valve. Vacuum
breaker relief is also recommended when face-and-bypass control is used.
Installation - Piping
53