Motorised High/Low Control B; High/Low Control - FULTON J Series Installation, Operation And Maintenance Manual

1.1
GENERAL
The Fulton motorised high/low control is designed to improve the efficiency of the boiler by switching
the firing rate from high fire (when there is low steam pressure in the boiler) to low fire (when the
boiler reaches a high steam pressure). The systems major components comprises of; two stage gas
valves, motorised air damper unit and two stage steam pressure switches.
The adjustment of the air gate control motor or the two stage
Air Damper Housing
High/Low Fire Cams
Air Damper Motor
1.2
OPERATION
With the steam pressure switch preset to the high and low fire operational requirements of the system,
and the boiler operating normally, steam pressure will gradually increase until the high pressure limit
is reached, the pressure switch will then switch the two stage gas valve and the air damper motor to
the low fire position.
The boiler will continue to operate at low fire until the steam pressure falls to the low pressure limit
setting on the pressure switch. At this point, the gas valve and the air damper will switch the boiler
into high fire mode and the sequence of high fire / low fire is regulated automatically with no routine
maintenance required.
Note: Should the boiler attain the off setting of the on/off control pressure switch, the burner will switch off on
low fire and then restart in the normal way on high fire.
1.3
ADDITIONAL CONTROLS
Low Fire Hold Switch - Used to maintain the boiler in the low fire mode during commissioning.
MOTORISED HIGH / LOW CONTROL
!
gas valve should only be carried out by qualified personnel,
incorrect adjustment could result in damage to the pressure
vessel and/or the production of harmful combustion gases.
FIG. 38 HIGH/LOW CONTROL
J DUAL FUEL MANUAL 02 2014 ISSUE 9
CAUTION
B
APPENDIX B
Page 69