Slant/Fin BOILERS Liberty, Cleaning And Filling A New Steam Boiler, Low Water Cut-Off Check-Out

LIBERTY II 9

CLEANING AND FILLING A NEW STEAM BOILER

I.BEFORE USING STEAM BOILER

A.Check burner to be certain it is ready for firing. DO NOT FIRE into an empty boiler.

B.Be prepared to heat raw water to at least 180°F. as soon as it is introduced into the boiler. This procedure will remove dissolved, corrosive gases.

C.Provide drain line, with valve, from boiler. Use a bottom tapping. Line and drain must be suitable for handling caustic solution.

D.Check for low water cut-off operation, see section below for check-out.

II.CLEAN STEAM BOILER SYSTEM.

A.Fill the boiler to water line indicated on the boiler.

B.Follow start-up procedure for burner and operate the boiler with steam in the entire system for 2 or 3 days to bring oil and dirt from the system to the boiler. While system is in operation, maintain the proper water level in the boiler by slowly adding water to the boiler.

C.Shut down burner, cool down boiler and drain system.

D.Procedure to dissolve oil and grease in boiler:

1.Fill boiler to proper water line.

2.Prepare a boil-out solution of sodium hydroxide (caustic soda) and tri-sodium phosphate:

NOTE: Use caution in handling chemicals. Caustic soda is harmful to skin, eyes and clothing.

(a)Proportions: 1 lb. of each chemical per 50 gallons of sys- tem water.

(b)Stir chemicals into water until dissolved and pour into the boiler through a top tapping. Replace plug.

3.Start the burner; boil the water for at least 5 hours; shut off the burner.

E.With CAUTION, drain the boiler solution to a safe location. DO NOT LEAVE SOLUTION SITTING IN SYSTEM OVER 2 HOURS.

F.Wash the water side of the boiler thoroughly using a high pres-

sure water stream. Fill and drain the boiler several times.

III.TREATING WATER FOR CORROSION CONTROL (This is not scale control)

A.Prepare a solution of sodium chromate. Proportions: 1 lb. per 50 gallons of boiler water.

B.Stir chemical in water until dissolved and pour into boiler

through a top tapping. Replace plug.

IV. FILLING AND VENTING THE STEAM BOILER

A.Refill the boiler to the indicated water line.

B.Bring water to boiling temperature, promptly.

C.The boiler is now ready to be put into service or on standby.

BLOWING OFF A LOW PRESSURE STEAM BOILER

A.A 1-1/2" NPT tapping is provided in the front of the boiler (tapping no. 9, figure 1) for use as a surface blow down to provide rapid skimming of oil and grease which accumulate on the surface of the water. The boiler should be blown down as outlined below.

B.Turn off electrical power supply to boiler. Allow boiler to cool down and steam pressure to reduce to zero before removing skimmer tapping plug. Check for steam pressure by testing the pop safety valve. Keep your hands and all parts of your body away from the discharge end of the safety valve. Drain boiler down one to two inches below skimmer tapping. The water might be hot. Remove skimmer plug slowly and carefully install a 150 psi malleable iron

1-1/2" NPT street elbow, a 1-1/2" NPT skimmer valve and length of pipe and place a bucket underneath the open end of the pipe. Cover bucket with a piece of cloth. (See figure 9)

C.Fill boiler slowly until water level is two inches from top of gauge glass. (This is the starting water level for skimming only.) Fire boiler to produce steam. If the system is heavily laden with oil, it may be diffi- cult to obtain much more than a pound or so of pressure. Set the pressure control at about 7 psi. The higher the steam pressure you can use, the better and faster the cleaning.

D. As steam develops, open the SKIMMER drain valve with caution to skim the oil and film from the top of the water. DO NOT open the boil- er drain valve. Close the skimmer drain valve when the water level drops to about 5" from the top of the gauge glass. The water may stop before the level drops to 5" below the top of the glass. Refill boil- er until water level is again two inches from the top of the gauge glass.

E. Repeat (D) above until all film is skimmed off and the water settles to a normal movement. Add make up fresh water to the boiler as described in (D) above, during the blow-off operation, to maintain the proper skimming water level in the vessel. Empty bucket frequently in order to see the difference in water cleanliness.

F.When surging has stopped and water is clean, and no film can be seen floating in the bucket, shut off boiler, drain down to level of skim- mer tapping, remove valve, plug skimmer tapping and refill the boiler to 24-1/2" water level. After 15 minute operation, readjust level to normal operating level of 25-1/2" from bottom of boiler (see figure 9). Check the pop safety valve for proper operation. Check the low water cut-off operation, see below.

G.The entire process may have to be repeated over a period of a few days on extremely fouled systems.

LOW WATER CUT-OFF CHECK-OUT

I. Electronic probe type low water cut-off

If this boiler is factory equipped with an electronic probe type low water cut-off, operation of cut-off should be checked at least twice a year as follows:

A.While boiler is running, drain down boiler water slowly through Boiler Drain Cock shown on page 4, just until light goes on. Boiler should shut down 10 seconds after light goes on.

B.Be sure that it is the low water cut-off and not the room thermo- stat, pressure cut-out, or other control that has shut off the burner.

C.Refill the boiler and repeat test.

D.Refill the boiler and reset controls for normal operation.

II.Float type low water cut-off

If this boiler is factory equipped with a McDonnell & Miller float type low water cut-off, the low water cut-off must be blown down (flushed), at least once a week.