21
• Adjust gas input to boiler by removing protective cap on
pressure regulator
,
and turning screw clockwise to
increase input and counterclockwise to decrease
input.
• Manifold pressures are taken at outlet side of gas
valve.
• To check for proper ow of natural gas to boiler, divide
input rate shown on rating plate by heating value of
gas obtained from local gas company. This determines
number of cubic feet of gas required per hour.
• With all other gas appliances off, determine ow of gas
through meter for two minutes and multiply by 30 to
get hourly rate.
• Make minor adjustments to gas input as described
above.
• Change burner orices if nal manifold pressure
varies more than plus or minus 0.3 inches water
column from specied pressure.
• Primary air adjustment is not necessary, therefore air
shutters are not furnished as standard equipment.
CHECK SAFETY CONTROL CIRCUIT.
Test ignition system safety shutoff device after placing
boiler in operation.
1.
Pilot: With main burner operating, turn pilot gas
adjusting screw clockwise until pilot gas is
turned off. Within 90 seconds main gas control closes,
shutting off gas to main burner.
2.
High Limit Control: Remove cover and note
temperature setting. Decrease this setting to minimum
and operate boiler. When the boiler water temperature
exceeds the control temperature setting, the control
will open the circuit, closing the automatic main gas
valve. See Figure 21.
CHECKING GAS INPUT RATE TO BOILER
Figure 21 - High Limit Control Location
Burner Access
Door
Gas Valve
High Limit and
Operating Control
Located Inside Boiler
P/N 240009041, Rev. C [04/30/2017]
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