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SETTING OF BOILER CONTROL PRESSURE SWITCHES
PRESSURE CONTROL SWITCH ADJUSTMENT
If boiler fails to maintain steam pressure in operating range, pressure control switch may require adjustment.
1. Start boiler and allow pressure to build up to operating level -15 PSI (
1kg/cm²
).
2. Check boiler pressure gauge. If gauge indicates 12 to 14 PSI, pressure control switches are properly adjusted.
3. If boiler does not come on when pressure gauge reads 12 PSI and does not go off when pressure gauge reads
14 PSI, proceed as follows:
WARNING:
Because power must be on to adjust pressure switches, be sure to protect against electrical shock.
a. Remove screws and lift front cover off control box.
b. Hand adjust operating pressure control switch (A) and high limit pressure control switch (B) by turning
adjusting nut (Knurled knob) clockwise to raise and counter clockwise to lower actuation point. Switch (A)
should be set so that boiler comes on when boiler pressure gauge reads 12 PSI and goes off when gauge
reads 14 PSI. Switch (B) should be set so that boiler will shut off if pressure reaches 15 PSI. If 15 lb. boiler is
used for 5 lb. operation, follow above instructions and then refer to “adjusting watts 3/4" pressure reducing
valve.
c. The actuation value (differential) is factory set and cannot be changed.
d. The cold water condensor thermostat is preset at factory.
e. Repeat steps, 1, 2, and 3. If 12 to 14 PSI boiler pressure gauge reading is obtained
during boiler operation, adjustment is correct. If proper adjustment cannot be made consult Trouble-Shooting
Guide in this manual.
f. After making adjustments, replace cover on pressure switch box.
