Modine MDB Série Manuel D'installation Et De Maintenance page 25

control aPPlications - 100% makeup air units - model mdB
Tables 25.1 through 25.3 show the sequence of operation for 100% Makeup Air Two Speed and VFD Airflow
Control Options and associated Control Types. Note that in all cases, the controlling thermostat is based on
the gas controls selected and the firing rate control is not controlled by the night setback thermostat.
For additional information on gas controls options, please see page 13-14.
table 25.1 - two speed vFd control types
changeover
switch setting
Low
High
# of exhaust Fans operating
operation
0
1
2
If used with the Two Speed VFD Airflow Control Option, the VFD low speed is factory set for a speed between 40% and 100% as specified by the customer. If VFD
j
low speed is 50% of high speed, then either fan can start the unit. If the low speed is higher or lower than 50% of high speed, it is critical that the exhaust fans always be
started in the same order.
table 25.2 - vFd with Building Pressurization controller control types
changeover
switch setting
None (power on)
changeover
switch setting
Occupied
Unoccupied
time clock
mode
Occupied
Unoccupied
table 25.3 - vFd Building management (ddc) system control types
changeover
switch setting
Unit enabled by contact
closure from DDC system k
changeover
switch setting
Unit enabled by contact
closure from DDC system k
note: The VFD varies the speed of the motor to provide between 40% and 100% of the total unit airflow, based on the analog signal received from the building
management system.
A separate inlet or discharge air damper is required if 100% shut-off of outside air is required when the unit is not operating.
k
control type "a" - manual high/low speed switch
Blower
operation
Continuous - Low
Continuous - High
control type "B" - high/low speed exhaust Fan interlocks
Blower
operation
Off k
Continuous - Low
Continuous - High
control type "a" - continuous operation
Blower
operation
Continuous
control type "B" - manual occupied/unoccupied switch with night setback stat
Blower
operation
Continuous
Intermittent k
control type "c" - time clock with night setback stat
Blower
operation
Continuous
Intermittent k
control type "a" - 4-20ma Building management control system analog signal
Blower
operation
Continuous
control type "B" - 0-10vdc Building management control system analog signal
Blower
operation
Continuous
air
delivery
100% OA (50% CFM) j
100% OA (100% CFM) j
air
delivery
None
100% OA (50% CFM) j
100% OA (100% CFM) j
air
delivery
100% OA
(40%-100% air volume)
air
delivery
100% OA
(40%-100% air volume)
100% OA
(40% air volume)
air
delivery
100% OA
(40%-100% air volume)
100% OA
(40% air volume)
air
delivery
100% OA
(40%-100% air volume)
air
delivery
100% OA
(40%-100% air volume)
7-500.10
controlling
thermostat
Per Gas Controls
Per Gas Controls
controlling
thermostat
Per Gas Controls
Per Gas Controls
Per Gas Controls
controlling
thermostat
Per Gas Control
controlling
thermostat
Per Gas Controls
Per Gas Controls (Enabled by Night
Setback Stat)
controlling
thermostat
Per Gas Controls
Per Gas Controls
(Enabled by Night Setback Stat)
controlling
thermostat
Per Gas Controls
controlling
thermostat
Per Gas Controls
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