21
BURNER SETUP & BOILER OPERATION
corrosion of the boiler and system components. Do
not use ethylene glycol or automotive antifreezes.
a. Make sure that the antifreeze supplier
can provide periodic testing of antifreeze
concentration and inhibitor level.
b. If an automatic fill valve is used, the solution
strength in the system must be checked to assure
that the antifreeze concentration has not been
overly diluted.
c. Local codes may require the addition of a
backflow preventer or manual fill only with
separation from the city water supply.
d. Consider the minimum temperature of potential
exposure in the system when deciding on the
antifreeze concentration. A concentration of
50% generally provides protection from freezing
to -30°F.
D2. FILL THE BOILER (STEAM BOILERS)
1. The normal water line for steam boilers with
gravity returns is shown in Figure 7.1.
2. For systems with pumped returns or boilers feed
units, the fill level will depend on the control being
used. Verify the unit maintains a water level that is
visble in the gauge glass and does not exceed the
normal water level shown in Figure 7.1.
3. Check all joints and fittings in the system piping for
leaks and repair as necessary
4. If the water hardness is high, use water treatment to
reduce the deposition of minerals in the boiler.
5 If the water pH is out of 7.5 to 11 range, add
water treatment chemicals to bring within range, if
required.
E. PURGE AIR FROM THE SYSTEM
(WATER BOILERS ONLY)
1. Purge the system using purge valves, isolating zones
in the process or use system vents. Do not operate
the pump(s) while purging. Pumps will hold air in the
eye of the impeller.
2. Allow the system to reach 180°F and use manual
vents, if installed, to remove any remaining air.
Watch the pressure gauge as the system approaches
180°F. If the pressure exceeds the design operating
pressure, check:
a. Fill valve pressure.
b. Expansion or compression tank operation and
sizing.
F. CLEAN THE BOILER
(STEAM BOILERS ONLY)
1. Clean the boiler within one week after initial start-
up. Cleaning will be more effective if boiler operates
a day or two to loosen sediment and impurities in
system.
2. Boiler must be cleaned to remove any accumulation
of oil, grease, sludge, etc. in the system. These
substances can cause foaming and surging of boiler
water, producing an unstable water line and water
carryover to system.
3. Connect a skim valve off the 1-1/2 NPT skim tapping
on rear of boiler. See Figure 7.1 (Section 7) for skim
tapping location. Run a 1-1/2 NPT drain line off
skim valve to a point of safe discharge.
4. Provide a means of supplying continuous fresh water
to the boiler for the cleaning process.
5. Use common washing soda, such as Arm and
Hammer Super Washing Soda. Mix 1/2 pound of
soda with water in a 10 quart pail. Pour the mixture
into the boiler through the safety relief valve tapping.
6. Open the skim valve. Fill boiler until water begins to
flow out of the valve.
7. Turn on burner. Allow boiler water to heat up to just
below steaming (180 - 200°F). Do not allow boiler
to steam; steaming mixes up contaminants instead of
floating them at surface.
8. Open make-up water valve to continually feed water
to boiler. Adjust flow to maintain water temperature
at 180 - 200°F.
9. Continue skimming boiler until water flowing from
skim tapping flows clear. This will take some time,
possibly several hours for a dirty system.
10. Turn off burner, close make-up water valve.
11. Drain boiler completely. Refill and drain one or two
times to wash out all washing soda.
12. Remove skim valve and piping. Pipe a nipple and
cap in the skim valve.
If gauge glass becomes dirty more contaminants
have worked loose in system. Repeat cleaning and
skimming process as needed to clean system.
NOTICE
Do not allow make-up water to flow too fast.
Excessive quantities of cold water may fracture
sections.
CAUTION
Do not leave boiler unattended while firing burner.
Operating boiler with water below minimum
permissible water level may fracture sections.
CAUTION
Cleaning the boiler requires the use of very hot water
and corrosive chemicals. Use care when handling to
prevent injury.
WARNING
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