FULTON VMP40 - High Pressure Limit Switch; Flame Scanner

Boiler Safety Testing – Fulton Vertical Steam Boilers
High Pressure Limit Switch:
 With the burner on and the boiler under pressure, lower the set pressure on the switch until it
trips and shuts down the burner. Ensure the pressure that the switch trips at is the same as the
boiler operating pressure.
 To test the manual reset button, wait until the boiler has fully completed the post purge phase.
Once the boiler is in the standby position, reset the switch to the original set point.
 Press the manual reset switch on the pressuretrol. This will ensure that the manual reset switch is
functioning correctly. The burner should not start until the reset button is pressed.
Operating Pressure Limit Switch:
 With the boiler under pressure, lower the set pressure on the switch until it trips and shuts down
the burner. Be sure that the pressure that the switch trips at is the same as the boiler operating
pressure.
 This switch is an auto reset.
 Reset the switch to the original set point. The burner should turn back on automatically.
Flame Scanner:
 Verify that the flame scanner is observing flame with the burner running.
 Turn boiler to the off position.
 NOTE
o Do not shut off gas supply with boiler operation. This can lead to a potentially dangerous
situation.
 Close both the main gas supply isolation valve and gas pilot line isolation valve.
 Turn the boiler to the on position. The boiler will proceed through the ignition sequence. Once
burner control completes the ignition sequence, the burner control should display fault code for
pilot flame failure.
 During the pilot sequence, burner control should not display any flame signal during scanner test
with gas valves turned to the off position. If flame signal is present, troubleshooting will be
required to identify cause of the spark pickup.
 Turn the boiler to the off position and open the gas pilot line isolation valve while leaving the
main gas isolation valve in the closed position. This will allow for the burner to cycle through
the pilot sequence and test main flame failure. The burner control should display fault code for
main flame failure. Turn the boiler off after this test is complete.
o Typically on boilers 30 HP and below, the pilot flame will be sufficient to allow the
boiler to cycle through the main flame test. If this occurs, slowly shut the pilot line
isolation valve. This will cause the boiler to fail on main flame.
 Once the boiler has completed the post purge cycle, turn the boiler to the off position. Open the
main gas supply valve, turn the boiler to the on position and resume normal operation.