Carrier 33ZCVAVTRM Spezifikationen PDF herunterladen (Seite 35)

HOT WATER OR STEAM HEAT — The zone controller

can be configured to control local heat provided by heating coils

carrying hot water or steam, governed either by a two-position

(on/off) valve or by a proportional (floating modulating) valve.

The heating coils can be installed in the air terminal (ducted), or

as perimeter heat. If modulating baseboard is used, refer to the

General Heating Information section for additional information.

Figure 22 shows the hardware configuration for a zone control-

ler applied to a series fan powered air terminal equipped with

hot water or steam heating coils. The diagram in Fig. 23 shows

how the zone controller controls an air terminal equipped with

two-position hot water or steam heat. The diagram in Fig. 24

shows how the zone controller controls an air terminal equipped

with proportional hot water or steam heat. The fan runs con-

stantly in all modes during occupied periods.

For modulating control, the supply air needed is compared

to the actual supply air to either drive the valve open or closed.

There is a deadband on the supply air deviation where the valve

will be left at the current position until the error gets larger than

the deadband.

For modulating type heat, the floating point function com-

pares the submaster reference from the PID loop to the supply

air temperature to calculate the direction and time to position

the valve. The control prevents both outputs from operating

simultaneously.

Configuration determines the logic output type for normally

open or normally closed type two-position valves.

HeatingwithIAQControl

— A feature is provided for situa-

tions in which additional primary air is required for ventilation

(IAQ).

The heating set point is calculated from the midpoint be-

tween the current heating and cooling set points.

The standard heating algorithm is used. The algorithm pre-

vents the space temperature from falling below the set point

before heating is activated. The air terminal must be in the

cooling mode and the equipment must be providing cooling.

When in unoccupied heating, the terminal’s fan will be

turned on to provide airflow to the zone. Also, in the unoccu-

pied mode, the primary damper will be held in its last com-

manded position. If the air source becomes active (on) during

this mode, the damper will be controlled normally.

NOTE: In a Linkage system the when the central fan is operat-

ing, the terminal fan will also be operating.

Parallel Fan Terminal Applications — The paral-

lel fan terminal provides three capabilities to the zone. First, it

allows for unoccupied heating if auxiliary heating is available.

Secondly, it allows CV heating when occupied (the fan is on

when ducted heating is on). Thirdly, it provides a means to pre-

vent cold air from “dropping” into the zone during cooling

mode.

The 33ZCFANTRM or 33ZCVVTZC-01 (with option

board) Zone Controllers provide heating control in three differ-

ent ways:

• positioning the primary air damper to a minimum air-

flow when the air source is in cooling mode and starting

the fan to utilize plenum heat as a first stage

• controlling an optional auxiliary heater mechanism to

provide heating

• modulation of the primary air damper when the air

source is in its heating mode (VAV Central Heating)

The 33ZCFANTRM or 33ZCVVTZC-01 (with option

board) Zone Controllers support three methods to control heat-

ing. These methods are as follows:

• two-position (on/off) control using a normally open or

normally closed heating valve

• modulating control using a normally open or normally

closed floating point heating valve

• modulating control using up to 3 stages of electric heat

COOLING — The primary control function of zone controller

is to provide cooling to the space by modulating the amount of

supply airflow through its primary damper.

The airflow set point is limited to a range of values that al-

low the air source to operate properly in the Cooling mode.

These configured limits are listed in the Installation Instruc-

tions for the zone controller. The minimum limit ensures that

the sum of all air terminal minimum airflow requirements fall

within the minimum cooling operating range of the air source.

The maximum limit ensures that airflow will not increase

above the maximum design value and that the noise level gen-

erated at this maximum airflow will be acceptable to the occu-

pants of the zone.

100%

MAX COOL LIMIT

(DAMPER OVERRIDE

PRESSURIZATION

MODE)

MAX HEAT LIMIT

MIN HEAT LIMIT

MIN COOL LIMIT

FULL HEATING

FULL COOLING

DEADBAND

COOL

WARM

OCCUPIED

COOLING

NTFC

SETPOINT

OCCUPIED

HEATING &

MORNING

WARM-UP

SETPOINT

DAMPER

OVERRIDE-

EVACUATION

MODE

ELECTRIC

HEAT

STAGES

% AIRFLOW

SPACE TEMPERATURE (DEGREES)

VENT POSITION

LEGEND

*Stage 1 is radial or baseboard heat with combination heat.

Fig. 21 — Sequence of Operation for Series Fan Powered Air Terminal with Staged Electric Heat

NTFC — Nighttime Free Cooling

Air Source Supplying Heated Air

Air Source Supplying Cooled Air

...... Ventilation Mode

NOTE: Ventilation mode occurs when air source mode is in cooling and

air source supply air temperature is above 65 F and below 75 F.

1 2 ... 30 31 32 33 34 35 36 37 38 39 40

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