To install a manhole or handhole plate, first center
the fitting in the opening. Make sure the shoulder does
not bind on the edges of the opening. Then slip the yoke
on and start the stud nut. Run the nut on the stud until it
is hand tight; then give the nut one-quarter of a turn
with a wrench. Do NOT tighten the nut enough to
compress the gasket.
When the boiler is given a hydrostatic test, the
pressure of the water usually forces the manhole and
handhole gaskets into place and thus ensures proper
seating. The plates are first set up lightly. When the
boiler is ready for testing, the pressure should be
pumped up to within 50 psi of the hydrostatic test
pressure, regardless of any leakage from the manhole
or handhole plates. Leakage is likely to be general at
first, but it decreases as the pressure is increased. When
the pressure is within 50 psi of the test pressure, most
of the leakage stops although the nuts are still loose.
If some plates are leaking badly, the trouble is
probably caused by improper seating of the gaskets. As
a rule, the gasket is caught on the outer edge between
the edge of the plate and the edge of the counterbore for
the seat. A light blow with a hammer on the outside of
the plate usually relieves the tension on the gasket and
allows it to seat properly.
After leaky gaskets have been adjusted and while
full test pressure is on the boiler, tighten up all plates
firmly. Use only the wrenches specified for this
Some economizer headers and a few superheater
headers are fitted with handhole plugs instead of
handhole plates. Also, some economizers have
bayonet types of cleanout plugs on the front ends of the
tube loops to allow access to the tubes at the return
bend end. Detailed instructions for installing and
removing the plug type of manhole fittings and the
return bend cleanout fittings are given in appropriate
manufacturers technical manuals.
The boiler should be given a hydrostatic test
annually or whenever the operator doubts the boiler
strength. The purpose of the test is to prove the
TIGHTNESS of all the parts of the boiler or the
STRENGTH of the boiler and its parts.
In preparing the boiler for a test, rinse it out with
fresh water. Then check carefully to see that no loose
scale or tools are left in any part of the boiler.
The procedures for making boiler hydrostatic tests
are as follows:
Close all openings and "gag" (clamp down) all
safety valves. Gags should be only hand tight
and straight. Do NOT use a wrench; it will bend
the valve stem and possibly damage the seat.
Remember that valves are easily damaged if
lifted by water pressure. Close all connections
on the boiler except air cocks, test pressure
gauge, and valves of the line through which
pressure is to be applied.
Reduce the water level in the boiler by opening
an air cock, and blow down the boiler until the
water level is below the feedwater inlet
connection. Clear the blowdown area before
Connect a hydrostatic pump between the boiler
and water service connection. Install all pipe
and fittings between the pump and the boiler.
Remember, the pipe and fittings must be able to
withstand test pressures. Install a hose between
the pump and the chosen water service. Ensure
the chosen water service supplies ample water
pressure to conduct the test.
Remove the plug from the feedwater inlet cross
by turning it in a counterclockwise direction.
Open the boiler casing access doors or plates, so
tube ends can be inspected during the test.
Install a wedge between the control switch and
the pressure-actuating platform. Also, install a
stop valve before the control switch to protect
the control, so hydrostatic pressure will not
actuate or damage the control. The range of the
pressure control is usually less than the
hydrostatic pressure being applied. Do NOT
bend or damage the actuating parts.
Fill the boiler with water until water discharges
out of the air cock; then close the air cock.
Ensure all the air is expelled from the boiler
before closing the air cock. Turn on the water
service valve. The water temperature should be
the same as the surrounding atmosphere. The
minimum water temperature must be 70°F.
Check the boiler steam pressure gauge in-line
cock to ensure that it is open. Ensure the
butterfly handle is in-line (parallel) with the