Absolute ABS-1500 - Page 65

Absolute Boilers ABS 1500-2000-2500-3000-4000
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a. Local operation via internal set point, The output of the boiler modulates on the basis of the ow temperature.
b. Remote operation via external signal (4-20mA) for output or temperature set-point
c. Lead/Lag (Cascade master control) communicates directly to each boiler via Modbus communication protocol.
Important!! – No frost protection when the boiler power is turned o
6. Air pressure switch calibration and check
a. Check sensing tube, connected no cracks or splits
b. Command boiler on, disconnect sensing tube from switch our air shroud
c. Boiler shall shutdown on air pressure switch open
d. Reattach sensing line and restart boiler and conrm correct operation
7. Low gas pressure calibration and check (manual reset)
a. Check for leaks around the surface mount of low gas pressure switch for gas leaks
b. Command boiler on, while starting turn dial to the maximum setting or until boiler shutdown on LCI (operating
interlocks), the switch is equipped with a LED indication when switch has activated.
c. Set switch setting back to 3.5” w.c., press the reset on switch and observe boiler shall start again automatically.
d. Conrm pressure via inlet test point of the gas valve (3), measure the pressure while operating in high
re position to conrm sucient gas pressure if available, inlet gas pressure lower than 3 ½ inch w.c. will
result in poor air/fuel ratio and reduce output. The gas pressure shall always be above the 3.5 inch w.c. at
all times. The switch will activate in low gas supply pressure conditions and shall not be circumvented.