Trane HUV Installation Operation & Maintenance page 33

About the Pneumatic Controls
Trane's pneumatic control pack-
age provides an ideal replacement
and retrofit in existing units or ad-
ditions currently designed with
pneumatic controls.
Located in the right hand end
pocket of the classroom unit venti-
lator, the pneumatic package sup-
ports a mixed air actuator,
discharge air sensor, and required
solenoids and pneumatic electric
(PE) switches required for proper
operation. See Figure 30 pneu-
matic package. Trane provides
the following selectable options
are also available with the control-
ler:
• Heating only room or zone
control
• 2-pipe zone control
• 4-pipe zone control
• Electric low limit thermostat
• Valve or face and bypass
control
• Valve or face and bypass con-
trol
DX
Note: Face and bypass is available
for 2-pipe CW and HW systems
only.
Zone vs. Room Control
Zone control provides the ability to
link several units together with a
single unoccupied night thermo-
stat. This enables the Unoccupied
cycle from one central thermostat
location.
UV-PRC001-EN
Controls
Pneumatic Controls
Room control provides flexibility
with a dual setpoint thermostat for
each unit. This provides the ability
to set a day temperature (occupied
mode) and a night temperature
(unoccupied mode) for each unit.
A single thermostat per unit is pro-
vided for day (occupied mode)
temperature setting with both
zone and room control.
During the unoccupied cycle for
zone control, the unit ventilators
are cycled on a zone basis (zone in-
dexing to be done by others).
When the unit ventilator is off, the
outside air damper is closed and
the heating valve is in an open po-
sition.
During the unoccupied cycle for
room control, the outside air
damper is closed and the hot wa-
ter valve is open. As the space
temperature drops below the un-
occupied setpoint, the fan will cy-
cle on and the outdoor air damper
will remain
closed. The
fan remains
Figure 30: Pneumatic package
on until the space temperature ex-
ceeds the unoccupied setpoint.
Note: The day/night changeover
system is field supplied and in-
stalled.
Morning Warm-up
When the space temperature is
greater than 3-degrees F below
setpoint, the outside air damper
remains closed. If the space tem-
perature comes within 3-degrees F
of setpoint the outside air damper
will modulate to minimum posi-
tion.
Low Temperature Protection
(manual reset device)
The low temperature thermostat
option senses the discharge air
temperature. Should the tempera-
ture drop below 38-degrees F (ad-
justable), the unit ventilator will
become disabled.
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