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8. Power Exhaust Operation
8.1.
Single Fan or Blower
The M2 has several exhaust control options selected by ECTO 8.16. The default operation, option 0, is single−stage ener-
gized when the fresh air damper opens to 50% Travel (ECTO 8.20). The blower must be operating.
Units equipped with an A133 (GP) board with the DIP configuration switch set to VAV, may control the fan by a building
pressure switch (S37 or S39) or a pressure transducer (A34).
8.2.
Two Fans or Blowers
Units equipped with two−stage exhaust fan and A133 (GP) board with the DIP configuration switch set to VAV, may control
the fan stage by two fresh air damper position setpoints, two pressure switches or from two pressure sensor setpoints.
8.3.
Exhaust Blower VFD
Units equipped with a power exhaust VFD and A133 (GP) board with the DIP configuration switch set to VAV, may vary the
speed of the blower to maintain a building pressure setpoint.
There are four exhaust fan enable options to choose from when the unit is equipped with a GP board:
1. On when blower is energized.
2. On always.
3. On during occupied period.
4. On if optional digital input A133_P194_1 is energized.
See table 28 for more details.
Single−Stage Exhaust
Option
Option
ECTO 8.16
Enabled when
0
Blower is energized.
CAV units with single stage exhaust fans use the A55_P265−11 output to energize the exhaust relay when the fresh air damper position reaches
50% Travel (ECTO 8.20) when the blower is operating. The exhaust will de−energize when the damper position decreases 10% (ECTO 8.21)
less than the setpoint or when the blower is de−energized.
VAV units with VFDs could use this option for single stage operation. In that case, the A55_P265−11 output is used to enable the VFD and the
exhaust fan will operate at speed set with ECTO 8.17 (50% default).
1
Always
2
Occupied
3
Blower is energized.
On units equipped with an A133 board set for VAV operation, the exhaust fan will be energized when enabled and the Digital Input 1 is energized. This
option typically would have a building pressure switch connected to the Digital Input.
VAV units with VFDs could use this option for single stage operation. In that case, the A55_P265−11 output is used to enable the VFD and the ex-
haust fan will operate at speed set with ECTO 8.17 (50% default).
4
Always
5
Occupied
6
Blower is energized
A133 Digital Input 1 (P194−1)
7
is energized (enable switch)
(1)
Settings require adjustment in most cases.
CAV units equipped with an A133 board set for VAV operation, the power exhaust will be energized when enabled and the Analog Input voltage is at or
above ECTO 8.20 setting. Exhaust air will de−energize when the voltage decreases by the deadband set with ECTO 8.21. This option typically would
have a building pressure sensor connected to the Analog Input.
VAV units with VFDs could use this option for single stage operation. In that case, the A55_P265−11 output is used to enable the VFD and the ex-
haust fan will operate at speed set with ECTO 8.17 (50% default)
Two−Stage Exhaust
8
8
Blower is energized
Blower is energized
(1)
Settings must be adjusted for proper operation.
Units equipped with an A133 board set for VAV operation and two−stage exhaust fans use the A55_P265−11 output to energize the exhaust relay for
stage one when the fresh air damper position reaches 50% Travel (ECTO 8.20) when the blower is operating. The A133_P194−5 output energizes
exhaust fan relay (K201) for stage two when the fresh air damper position reaches (ECTO 8.23) when the blower is operating. ECTO 8.23 must be
adjusted for this operation. Stage 2 will de−energize when the damper position decreases the % set with ECTO 8.24 less than the setpoint or when the
blower is de−energized. Stage two will not energize until 0 seconds default (ECTO 8.25) after stage one. Stage 1 will not de−energize until stage two
has been de−energized for 100 Seconds (ECTO8.22).
506457−01 05/10
Table 28. ECTO 8.16 Exhaust Control
Input
Fresh Air Damper Position
A133 Digital Input 1 (P194−1)(TB18−1)
A133 Di it l I
t 1 (P194 1)(TB18 1)
(Pressure Switch S37)
(Pressure Switch S37)
A133 Analog Input 2 (P194−7) (TB18−7)
A133 Analog Input 2 (P194−7) (TB18−7)
(Pressure Sensor A34)
(Pressure Sensor A34)
Input1
Input2
Fresh Air Damper Position
Fresh Air Damper Position
Page 34
8.
Power Exhaust Operation
Setpoints
Default
ECTO
Default
50% Travel
8.20
10% Travel
Input energized by pressure switch setting.
p
g
y p
(1)
(1)
−0.3"w.c.
8.20
0.04"w.c.
Setpoints #
Deadband
50% Travel
8.20
1
20% Travel
10% Travel
8.21
2
64% Travel
Deadband
ECTO
8.21
g
(1)
(1)
8.21
8.23
8.24
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