Sequence Of Operation, Vav Units Only; 50Bvj,W; Control Source (Run Conditions); Digital Input - Carrier Omnizone 50BVC Installation, Start-Up, Service And Controls Operation And Troubleshooting

Fig. 25 — Flex and Expansion XNET Connection
Alarms
• Leaving water temperature high/low trip
• Discharge air temperature high/low trip
• Entering water temperature high/low trip
• Sensor failure alarm
• Unit filter runtime trip (optional)
• Comp 1 runtime trip
• Comp 2 runtime trip
• Comp 3 runtime trip
• Comp 4 runtime trip
• Freeze stat sensor UPM alarm (optional)
• Low pressure sensor UPM alarm
• High pressure sensor UPM alarm
• Low pressure sensor UPM alarm
• High pressure sensor UPM alarm
• Condensate overflow UPM alarm
• High/low voltage UPM alarm
Sequence of Operation, VAV Units Only —
See the integration points list on page 65 for
50BVJ,W —
specific points and values.
CONTROL SOURCE (RUN CONDITIONS) — The
may have external or internal control sources to initiate
heating or cooling operation.
EXTERNAL CONTROL SOURCE — The unit may be
controlled from the following external sources:

• Digital input

• BAS – Building Automation System

• Manual on

DIGITAL INPUT — Provides a method of running the unit
by providing a contact closure (On/Off) to UI-12. Digital in-
put provides a simple interface for enabling unit operation.
Once enabled, the unit will run until the occupied set point
has been satisfied.
BAS — Provides a network interface to the heat pump. The
I/O Flex 6126 controller supports the following building au-
tomation protocols:
BACnet
Modbus
LonWorks
MANUAL ON — Places the unit in manual run mode; the
unit will operate until the set point is satisfied.
INTERNAL CONTROL SOURCE (KEYPAD) — All con-
trollers are provided with a battery backup real time clock.
When configured for Keypad, the internal scheduler uses the
local time and user schedule to initiate unit operation. Occupied
Schedule: 56 F supply air set point (adjustable).
Unit Mode —
heat pump per its specific design configuration and applica-
tion. A unit mode may be selected from the following:

• Cooling only

• Cooling only with hot gas re-heat

COOLING ONLY — The unit is configured for mechanical
cooling.
COOLING ONLY WITH HOT GAS RE-HEAT — The unit
is configured for cooling only with active humidity control.
Please see Discharge Air Control with Modulating Re-Heat for
additional details.
Fan Modes —
type of fan hardware being used with the unit. Fan hardware
is application specific and will determine the behavior for
the specific application for which it is being applied.
The Fan option may be configured with one of the follow-
ing options:
• Supply Air Fan (SAF) Start/Stop (also known as On/Off
signaling)
• Variable Frequency Drive (or Variable Fan used in VAV
unit
applications)
• Return Fan interlock with Supply Fan (If SAF runs RAF
runs)
START/STOP FANS — The fan enable signal is provided
on BO-1 of the I/O Flex 6126 controller; operation is inter-
locked with cooling and re-heat operations. The return air
fan can be enabled via the BACview tool, and it will be
commanded 5 seconds after the supply fan has been en-
gaged at all times.
The supply fan can also be set to stop if the return fan is in
alarm via the BACview tool.
VARIABLE FREQUENCY DRIVE (VFD) FAN — The
VFD uses an analog signal (0 to 10V) to control the speed of
the blower. This signal is output from Analog Output 1 (AO-
1) of the I/O Flex 6126 controller.
45
COMMUNICATION PROTOCOL
Building Automation and Control network
Common open industrial protocol standard
LonWorks Automation and control network
(Card required)
The Unit Mode is used to configure the
The Fan mode option is used to select the