Carrier 50EJQ Información técnica descargar pdf (Pagina 5)

Sequence of Operation (Expansion Module) —

For CV, VAV, or heat pump units equipped with optional ex-

pansion I/O (input/output) board, the following functions will

be added to the sequence:

1. The expansion control board will perform a periodic SIO

scan and maintain I/O database expanded I/O points.

2. Fire/Smoke Control is performed.

3. If the unit is in Occupied mode (or indoor fan is ON for

thermostat units), the expansion control board will per-

form IAQ control.

4. The fan, ﬁlter, demand limit, and ﬁeld-applied status is

monitored.

OPERATION

Constant Volume Operation with Thermostat —

Although these units are designed for operation with room

sensors conﬁgured with an occupancy schedule and CCN

compatible for comfort heating and cooling, the unit is also

compatible (without additional hardware) with a two-stage

heat and two-stage cool thermostat. Thermostat inputs and

outputs are shown is Tables 1 and 2.

Table 1 — Thermostat Operation Inputs

INPUTS TYPE

TSTAT DIP switch no. 2

Heat Type DIP switch no. 7

AC/Heat Pump DIP switch no. 8

G Discrete Input

Y1 Discrete Input

Y2 Discrete Input

W1 Discrete Input

W2 Discrete Input

Enthalpy Switch Discrete Input

Supply-Air Temperature (SAT) Analog Input

Outdoor-Air Temperature (OAT) Analog Input

Minimum Position (IQMP) Internal Parameter

Supply-Air Set Point (SASP) User Conﬁgured

(default = 55 F)

High OAT Economizer Lockout (OATL) User Conﬁgured

(default = 65 F)

Table 2 — Thermostat Operation Outputs

OUTPUTS TYPE

Thermostat Operation Mode Internal Parameter

Indoor Fan Discrete Output

Compressor 1 Discrete Output

Compressor 2 Discrete Output

Economizer Position Analog Output

Heat 1 Discrete Output

Heat 2 Discrete Output

THERMOSTAT OPERATION MODE — The thermostat mode

is only operational on CV or heat pump units. If the DIP

switch is set for thermostat operation, the control will set

Thermostat Operation mode (TSTAT) and clear all other modes.

In Thermostat Operation mode the function of the control

will be limited. See Fig. 1 and 2.

Indoor Fan — When in Thermostat Operation mode, the in-

door fan will operate in the following way:

• when G input is energized, turn on indoor fan and open

economizer dampers to the minimum position (IQMP)

• when G input is deenergized, turn off the indoor fan and

close the economizer dampers.

• when the unit has electric heat or is a heat pump, turn on

the indoor fan whenever there is a call for heat.

For a further explanation of the economizer damper mini-

mum position (IQMP) see the Indoor-Air Quality Sequence

of Operation section on page 15.

Cooling — When in Thermostat Operation mode, the G ter-

minal must be energized before cooling can operate. When

G is initiated and there is no call for cooling, the economizer

will be at the minimum position (IQMP).

The control will determine if outdoor conditions are suit-

able for economizer cooling. The conditions are suitable when:

• Enthalpy is low

•OAT≤OATL (see Table 1)

• SAT reading is available

• OAT reading is available

When all 4 of the above conditions are satisﬁed, the con-

trol will use the economizer as the ﬁrst stage of cooling. When

Y1 input is energized, the economizer will modulate to main-

tain SAT at the Supply-Air Set Point (SASP). When SAT is

above SASP, the economizer will be 100% open. When SAT

is below SASP the economizer may modulate between mini-

mum position and 100%. When Y2 is energized, and SAT is

less than SASP, the control will bring on compressor no. 1

and continue modulating the economizer as described above.

If SAT remains above SASP for 15 minutes, compressor no.

2 will be started. When Y2 is deenergized, the last stage of

compression will be dropped. When Y1 is deenergized, the

control will drop all DX cooling, and drive the economizer

to the minimum position if the thermostat fan switch is in

the ON position, or will close it if the thermostat fan switch

is in the AUTO position.

If the outdoor conditions are not suitable, the control will

keep the economizer at the minimum position and cycle com-

pressor no. 1 and 2 based upon Y1 and Y2 respectively.

The control will lockout the compressors if the SAT is too

low: compressor no. 1 lockout at SAT <40 F and compres-

sor no. 2 lockout at SAT <45 F.

After a compressor is locked out, it may be restarted again

after a normal time guard period.

Heating — When in Thermostat Operation mode, the in-

door fan must be on for electric heat. Heat 1 will follow W1

input. Heat 2 will follow W2 input. Heating and cooling

will be mutually locked out based on which mode was ini-

tiated ﬁrst.

Heating (Heat Pump) — When in Thermostat Operation mode,

the indoor fan will be on. Compressor no. 1 and 2, and re-

versing valve solenoids 1 and 2 will follow W1 input. Heat

stages 1 and 2 will follow W2 input. The unit will follow

calls for defrost with timed defrost cycles.

Heating and cooling will be mutually locked out based on

which mode was initiated ﬁrst. The control will maintain com-

pressor time guards and safety checks at all times.

1 2 3 4 5 6 7 8 9 10 ... 43 44

Comentarios a estos manuales

Sin comentarios

Carrier 50EJQ Información técnica Pagina 5

Comentarios a estos manuales

Relacionado con productos y manuales para Detectores de humo Carrier 50EJQ