Trapping Steam Tracer Lines - Xylem Bell & Gossett Hoffman Speciality Series Engineering Data Manual

Each individual steam tracer line requires a
separate trap to assure condensate drainage.
When more than one tracer line is manifolded
into a common trap, condensate can back up
in the line with the greatest pressure drop.
Individual tracer line trap selection guide:
1. Bucket Traps may be used for tracer lines
in areas not subject to freezing. The tracer
lines should be installed for gravity
drainage when Bucket Traps are used.
Condensate will drain at saturation temper-
ature for maximum heat transfer. Bucket
Traps are normally too expensive for larger
tracer applications.
2. Thermodisc Traps were designed for tracer
line applications. The pulsation of the ther-
modisc opening will cause condensate col-
lected at low points to move through the
tracer line. When installed according to
manufacturer's instructions, Thermodisc
Traps completely drain all condensate from
the body when the steam is off, to prevent
freezing. Thermodisc Traps drain conden-
sate at saturation temperature for maxi-
mum heat transfer. They are inexpensive
and the Hoffman 650 Series allow com-
plete replacement of the seat and disc
without removing the trap body from the
line.
3. Thermostatic Traps open in response to
temperature, not condensate level. Use
where maximum heat transfer is not impor-
tant. Thermostatic Traps normally open
10° to 30°F. below saturation temperature
to extract the maximum Btu's from the
steam before draining condensate.
Applications using Thermostatic Traps
should be pitched to allow gravity conden-
sate drainage. Thermostatic Traps select-
ed for tracer lines should fail open. When
the steam is off, the thermostatic element
will open draining condensate to prevent
freezing.
4. F & T Traps should never be used for trac-
er line applications. They are subject to
freezing when located in low ambient con-
ditions when the steam is off. They are
more expensive and normally fail in a
closed position.
CORRECT
WRONG
1. Each tracer line must have its own trap.
2.A common trap with manifold tracer lines may cause short cir-
cuiting through lines with lower pressure drop.
3. Longer lines will back-up condensate and will not provide ade-
quate heat transfer.
Trapping
Steam Tracer
Lines
39