Difference Between Flash Steam and Live Steam
T h e following descriptions apply to visual observation.
(a) If the trap discharges to a closed condensate return system, it must
have a slaved test discharge pipe open to the atmosphere installed downstream
o f the trap.
(b) A properly operating trap will discharge condensate and flash steam
a s it cycles. Some types of traps (inverted bucket, disk) have an
intermittent discharge, others (float, F&T) should have a continuous
condensate discharge, and certain types (thermostatic) can be either. The
presence of a continuous live steam discharge is a problem. The lack of any
d i s c h a r g e also indicates trouble.
( c ) Inspectors should realize that when a trap is under a fairly heavy
load the discharge produces considerable flash steam. A faulty trap may be
l o s i n g a significant amount of live steam that cannot be detected. In a
condensate discharge of, for example, 1 0 0 lb/hr a loss of 10 lb/hr of live
s t e a m will not be visually detectable. This relatively small loss can amount
to the cost of a new trap in 2 to 3 months. T h e r e f o r e , if a trap is suspected
of being faulty, always check your visual inspection with another method.
( d ) A basic part of visual inspection is determining if the trap is cold
or hot at operating temperature. One method is to squirt water on the trap
top and observe its reaction. The water will not react on a cold trap, but
will bubble and bounce on a hot trap.
2 . 3 . 2 Sound Detection. L i s t e n i n g to traps operate and judging performance
and potential malfunction are convenient inspection methods when working with