© 2018 OJ Electronics A/S
9
INSTRUCTIONS Commissioning guide for AHC-3000
8.1
Fire alarm
This fire alarm is detected on a digital fire input on the AHC-3000 controller.
The signal may possibly come from an automatic fire detection system (AFD) or an external fire
thermostat placed in the duct system.
If the digital input (fire alarm) detects the fire alarm (fire alarm = open contact), the AHU will enter
fire mode and the fan speed will assume the status selected in parameter “
Supply fan speed
”
/“
Exhaust fan speed
” (see fig. 8.3).
If a 0% fan speed is selected in both parameters, the AHU will stop and the dampers will close.
8.2
AHU internal fire alarm
This fire alarm uses the supply air and exhaust-air temperature sensors in the AHU to detect a fire
alarm. If the current value of the “
Supply temperature
” or “
Extract temperature
” is beyond the
setpoint (see fig. 8.3), the AHU will go into fire alarm mode and emit a fire alarm: “A” alarm. This fire
alarm will stop the fans.
9. Balancing
This function allows the installer to maintain a constant fan speed during the air-distribution
adjustment of, for instance, the manual dampers in a CAV application.
Selecting “Lock fan” will set the fan speed at the current value.
The fans will remain at this speed for eight hours – and the system will automatically return to normal
operation after this period of time has elapsed.
If the balancing job is finished before time runs out, you can manually return the function to “
Normal
operation
”.
Info:
Frost protection of the water heating coil is active during the balancing function – the normal
temperature control is active.