inches of water for each pound of pressure differential
locate the source of trouble. If drain A is stopped but B
and C are running, the trouble is located somewhere in
between the trap and the drainage system.
section 1 of the drain line. If the A and B drains are
Inefficient trap operation is usually caused by one
stopped but C is running, the trouble is in section 2. If
of the following problems:
A, B, and C are stopped but F is running, 3 is the section
that needs attention. If A, B, C, and F are stopped but D
and E are working, check section 8. If D is working and
The discharge valve is leaking because of
E is stopped up, check section 4. If E is running but D
scoring by dirt or scale.
is stopped, check section 5. If both D and E are stopped
The discharge valve is leaking because of a
but A, B, C, and F are running, the trouble will lie
punctured float or basket.
somewhere in section 6. If all these facilities are
stopped, the trouble will be located at section 9.
The working parts are adrift.
The discharge valve is too small.
The discharge valve does not seat properly.
Strainers are installed in piping systems to prevent
The trap is air bound.
the passage of foreign matter that could obstruct valves
or damage the machinery or appliances.
The sediment has collected in the bottom of the
Use these procedures to clean a strainer fitted with
a drain in the bottom and an air cock vent in the top or
The trap does not accumulate enough water to
cover. Close the valves leading to the strainer and open
both the drain and the vent cock. This permits the
discharge of oil and sludge and purges the chamber of
The bypass valve is open or leaking.
air. Close the drain before you reopen the valves. Then
close the vent after you have reopened the valves.
If the discharge valve is too small, it may be
When no air cock vent is provided in the strainer cover,
possible to enlarge the discharge orifice, but only if the
first close the valves leading to the strainer and then
float leverage will handle a larger valve. If the internal
open the strainer cover. Do the latter step gradually
load on the valve equals or exceeds the pulling power
because, if the strainer is air bound, oil and foreign
of the leverage, the valve will not open. It may be
matter will spray out. Remove the strainer basket,
possible to raise the leverage, or it may be easier to
replace it with a clean one, secure the strainer cover, and
direct part of the discharge to another trap. However,
open the valves. Check to make sure there are no leaks.
never overload a trap by leading too many additional
Clean, spare strainer baskets of the necessary size
drains to it. Keep this in mind when you make
and type, plainly marked or tagged, should be kept in a
alterations in a piping system.
rack convenient to each strainer. The removed basket
can usually be cleaned with a jet of steam. If it is heavily
encrusted, it should be boiled in a solution of boiler
at less than capacity, you can crack the bypass valve
just enough to carry off the excess water. Remember
that if the quantity of condensate diminishes, the bypass
valve will deliver steam. If a trap does not accumulate
enough water, pour one or two buckets of water on the
Traps must be located below the lowest point to be
drained. Also, they should be easily accessible for
overcome the trouble. If not, you will have to shut off
inspection and repair.
the trap, remove a fitting, and prime with water through
The capacity of a trap is determined by the ejection
pressure, the pressure against which it is discharged, and
Inspect drainage systems regularly to detect leaks
the area of the discharge orifice. Proper observance of
that could easily pass unnoticed. In freezing weather,
pressure limits is necessary if traps are to function
the drains for auxiliary machinery in exposed locations
efficiently. They should not be subjected to pressures
should be drained. If necessary, they should be broken
higher than those that they are designed to carry. A trap
will normally discharge condensate against a head of 24
to prevent possible damage to the machinery.