Honeywell CVL4022ASVAV1 Engineering Manual page 26

REHEAT
MODE
100
PERCENT
OPEN
REHEAT
FLOW
HeatOccSpt
Periph Min Pos
Fig. 27. VAV box modes for Reheat Type Float_Reheat/
Float_Periph, no minimum position, reheat goes to zero
percent in cooling mode Non-proportional (suited for
Reheat control because the Reheat closes to zero percent
at HeatOccSpt).
Reheat Type: Float_Reheat/Float_Periph.
Proportional Reheat Flow: Disable.
Periph Min Pos: 0% or greater.
REHEAT
100
MODE
PERCENT
OPEN
REHEAT
POS.
(DAMPER)
MIN
POS.
M11833
HeatOccSpt
Fig. 28. VAV box modes for Pressure Dependent, Reheat
Type Float Reheat/Float_Periph.
A Series fan is intended to run continuously when the main air
handler is on and is in-line with the primary air flow through
the box. This configuration is sometimes referred to as
Variable Volume Supply with Constant Volume Discharge
(VVS/CVD).
NOTE: The location of the heating coils can be in the dis-
charge, as shown in Fig. 29, or in the plenum return.
31-00083—02
COOLING MODE
MAX
FLOW
MIN
FLOW
CoolOccSpt
M11825
COOLING MODE
MAX
FLOW
(POS)
MIN
FLOW
(POS)
CoolOccSpt
Periph Min Pos
AIR FLOW
SENSOR
PRIMARY
AIR
DAMPER
ACTUATOR
1 1 1 1 1 1 1 2 2 2 2 2
3 4 5 6 7 8 9 0 1 2 3 4
1 1
1 2 3 4 5 6 7 8 9 0 1 2
Fig. 29. Series VAV box fan.
A parallel fan, see Fig. 30, is not located in the primary air
stream, but is designed to add return air from the plenum into
the air stream delivered to the space. The Controller turns on
the parallel fan when the space temperature falls below
Setpoint as a first stage of reheat (Parallel Temp), or if the air
flow falls below a minimum air flow setpoint to maintain a
minimum air flow to the space (Parallel Flow).
NOTE: The location of the heating coils can be in the
discharge, as shown in Fig. 30, or as part of the
plenum air return, either before or after the fan.
AIR FLOW
SENSOR
PRIMARY
AIR
DAMPER
ACTUATOR
1 1 1 1 1 1 1 2 2 2 2 2
3 4 5 6 7 8 9 0 1 2 3 4
1 1
1 2 3 4 5 6 7 8 9 0 1 2
Fig. 30. Parallel VAV Box Fan.
See Fig. 31 and Fig. 32 to see the Heat/Cool Modes for
Parallel Temperature/Flow VAV box fans.
26
REHEAT
COIL (OPTIONAL)
FAN
DISCHARGE
AIR
OPEN TO
FAN
PLENUM
VALVE
RELAY
REHEAT
COIL
DISCHARGE
AIR
FAN
FAN
VALVE
RELAY
RETURN AIR
FROM PLENUM
T7770
70
M33869
T7770
70
M33870