General description of control operation
Low water cutoff
Shuts down boiler if there is a low water condition.
Steam relief valve
Provides discharge if boiler pressure exceeds 15 psig.
Pressure limit control
If high steam pressure occurs, control shuts down burners until
pressure drops. Limit should be set higher than design pressure
of system. Operating control can be set at 5 psig and adjusted to
comfort level. Normal operation is usually less than 5 psig. At
certain times the system may operate under vacuum conditions.
Gauge glass
Indicates boiler water level. Cold fill water level should corre-
spond to line stamped on boiler jacket. When boiler operates,
water level will fluctuate.
Pressure gauge
Provides reading of boiler pressure. Maximum boiler pressure
is 15 psig.
Tankless water heater
Weil-McLain tankless heater ratings are based on 200°F boiler
water temperature. To get rated output, set tankless heater con-
trol to 200°F. Control can be adjusted to meet system hot water
requirements.
Burner adjustments for packaged and
non-packaged boilers
Final burner adjustments must be made using
combustion test equipment to assure proper opera-
tion. Do not fire boiler without water or sections
will overheat.
1. Refer to burner manual for start-up.
2. Allow boiler to heat to design condition.
3. Using combustion test equipment, adjust burner for:
a. CO2 between 11% and 12% and 0 smoke.
b. -0.01” to -0.02” W.C. draft in combustion chamber.
Controls requiring annual service
Float-type low water cutoff
Follow instructions to blowdown cutoff on page 4. Also refer
to instructions from cutoff manufacturer in envelope assembly
provided with boiler.
Probe-type low water cutoff
Cutoff must be removed and inspected and cleaned annually.
Refer to cutoff manufacturer’s instructions in envelope assembly
provided with boiler.
Steam relief valve
Check operation of steam relief valve. Follow instructions on
label fastened to relief valve.
Scald potential. Do not check operation of relief
valve unless discharge piping has been installed ac-
cording to Boiler Manual. If piping is not in place,
a qualified service technician must properly install
piping.
Gauge Glass
To clean glass:
1. Close lower gauge glass cock and carefully open petcock
below glass to blow water and sediment out of glass by steam
pressure.
2. Slowly open lower gauge glass cock and allow a small amount
of water to flush out through the open petcock.
3. Close petcock and fully open lower gauge cock. The water
level should immediately rise to its proper level.
4. If gauge glass breaks, close off both gauge cocks and loosen
glass retaining nuts to remove gauge glass. Do not use thin
glass tubing as a replacement.
Detailed service procedures
(continued)
Part number 550-141-829/1211
36
GOLD
SGO
OIL-FIRED NATURAL DRAFT STEAM BOILER — SERIES 3 —
Boiler Manual
SERVICE TECHNICIAN ONLY — read and follow completely.
