2.8.1
Single speed fans
The Fan On Pressure is programmable under the PROGRAM key. When the discharge pressure is > Fan On
Pressure and the fan delay timer has expired, the fan stage is incremented by 1. After incrementing the fan stage the
fan delay timer is set to 5 seconds and the Fan On Pressure is ramped from 1.4 BARG over the original value back to
the original value over the next 20 seconds.
The Fan Off Pressure is equal to the Fan On Pressure minus the Fan Diff Off Pressure which is programmable under
the PROGRAM key. When the discharge pressure is < Fan Off Pressure and the fan delay timer has expired, the fan
stage is decremented by 1. After decrementing the fan stage the fan delay timer is set to 5 seconds and the Fan Off
Pressure is ramped from 1.4 BARG below the original value back to the original value over the next 20 seconds
The following tables show the relationship between fan stages and the microprocessor digital outputs and fans:
1
-
11
Form 201.26.OI1(11/09)
Systems with 2 fans
FAN OUTPUTS 1
1-MF1, 2-MF1
FAN OUTPUTS 2
1-MF2, 2-MF2
=AMB-XTB7-8 (SYS1)
=AMB-XTB7-9 (SYS1)
=AMB-XTB10-8 (SYS2)
=AMB-XTB10-9 (SYS2)
0
OFF
OFF
1
ON
OFF
2
ON
ON
STAGES
Systems with 3 fans
FAN OUTPUTS 1
1-MF1, 2-MF1
FAN OUTPUTS 2
1-MF2, 2-MF2
FAN OUTPUTS 3
1-MF3, 2-MF3
=AMB-XTB7-8 (SYS1)
=AMB-XTB7-9 (SYS1)
=AMB-XTB7-10 (SYS1)
=AMB-XTB10-8 (SYS2)
=AMB-XTB10-9 (SYS2)
=AMB-XTB10-10 (SYS2)
0
OFF
OFF
OFF
1
ON
OFF
OFF
2
ON
ON
OFF
3
ON
ON
ON
STAGES
Systems with 4 fans
FAN OUTPUTS 1
1-MF1, 2-MF1
FAN OUTPUTS 2
1-MF2, 2-MF2
FAN OUTPUTS 3
1-MF3 & 1-MF4, 2-MF3 & 2-MF4
=AMB-XTB7-8 (SYS1)
=AMB-XTB7-9 (SYS1)
=AMB-XTB7-10 (SYS1)
=AMB-XTB10-8 (SYS2)
=AMB-XTB10-9 (SYS2)
=AMB-XTB10-10 (SYS2)
0
OFF
OFF
OFF
1
ON
OFF
OFF
2
ON
ON
OFF
3
ON
OFF
ON
4
ON
ON
ON
STAGES
