Honeywell T7984 A 사용자 설명서

T7984 A,B,C ELECTRONIC MODULATING CONTROL THERMOSTATS

Output 2 On/Off (T7984B only)

A 24 Vac on/off output which is normally used to control terminal

reheat in a zoned system. Example: electric base board relay,

electric duct heater relay, perimeter on/off 24 Vac valve, etc.

This output can also be used for cooling applications with the

mode jumper installed (See the control curves for T7984B)

There is a status LED mounted internally that indicates the

action of the output. The red LED indicates that the output

electronic contact (triac) is energized.

This electronic contact (triac) is rated at 1.1A max. in rush and

0.5A running. This electronic contact (triac) is protected with a

PTC self-resetting fuse. In the event of an overload or a short

circuit, the PTC self-resetting fuse will reduce the load to a

very low level. If the power is removed or the overload or the

short disappears, the PTC fuse will return to its normal state

and allow normal operation.

CPH (Cycles per Hour)

It is possible to fix the number of time per hour the reheat end

device will be energized. Those settings are adjusted with DIP

switch (S1).

Two different settings are possible:

4 cycles per hour or 8 cycles per hour

Use the following setting for the following reheat device applications:

Table 5. Cycle settings for reheat device applications

4 cycles per hour

8 cycles per hour

Anything using a gas fired or

oil fired terminal reheat device

N.C. 24 Vac thermal valve

(Hot wax thermal body valve)

Any gear driven end device

valve or damper actuator
Properly sized electric base

board strip

Oversized capacity electric

base board strip

Properly sized electric duct

heater

Oversized capacity electric

duct heater

Output 2, Modulating Analog Output 2 to

10Vdc (T7984C only)

A modulating signal that uses a variable Vdc signal for the

control of analog valve actuator or SCR power controller

which is normally used to control terminal reheat in a zone

system.

This type of output on the T7984C uses a half wave rectifier

bridge. If the same transformer is to be used for the

thermostat and the end device, be sure to select end devices

which also use a half wave rectifier bridge.

There is a status LED mounted internally that indicates the

action of the output. The red LED intensity is proportional to

CHECKOUT

Service LED

All thermostats have internal service LED & a system status

Led on the cover. The internal service LED are colored lights

that can be viewed from the side of the thermostat they are

energized and the system status LED is the one mounted on

the cover. (See the checkout & start up procedures section.)

Table 6. System Status LEDs

Thermostat operation can be confirmed with the System

status LED on the thermostat cover.

Model

Color

Explanation

T7984A

green High intensity = Demand for cooling or

heat.

Low = no demand.

T7984B,C red

Flashing = Night setback/set-up

activated.

Table 7. Internal Service LEDs

C Color

Indication when

•

• green Intensity is proportional to output 1

•

red

On/off output 2 is closed (load

energized)

• red

Intensity is proportional to reheat

output

Test Condition:

1. No contact changeover input and changeover sensor

disconnected. No wire on mode input.

2. T7984B & C: set DIP switch S3 and S4 to —ON“ position

to remove 75°F (24°C) limitation.

3. Room termperatures must be between 60-80°F.

Table 8. Knob position

Rotate Knob to: Green

Red (reheat models only)

T7984B & C

Minimum Position ON

OFF

Maximum Position OFF

The night setback feature can be temporarily overridden for 2-

1/2 hours by depressing the override button on the thermostat

cover.

the action of the output.

Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
customer.honeywell.com

Honeywell Limited-Honeywell Limitée
35 Dynamic Drive
Scarborough, Ontario M1V 4Z9