Honeywell chronotherm t8621a Benutzerhandbuch

15

68-0058—1

T8621A,C,D

INSTALLATION

M1546A

SYSTEM
TRANSFORMER

R

C

W1

W2

B

HEATING
CHANGEOVER 
RELAY

O

Y2

Y1

G

RC

COMPRESSOR 
CONTACTOR

COOLING 
CHANGEOVER 
RELAY

FAN RELAY

HEAT 2

HEAT 1

HIGH
LIMIT

HIGH
LIMIT

L1
(HOT)

L2

HEAT

OFF

COOL

SYSTEM
SWITCH

COOL 1

COOL 2

AUTO

ON

FAN
SWITCH

NON-ELECTRIC

ELECTRIC

POWER SUPPLY.  PROVIDE DISCONNECT MEANS AND 
OVERLOAD PROTECTION AS REQUIRED.

FAN OPERATION SWITCH MAY BE IN EITHER POSITION.

1

2

NOMINAL 24 VAC POWER MUST BE PRESENT BETWEEN R AND C FOR 
THERMOSTAT OPERATION.

DENOTES THERMOSTAT TO SUBBASE INTERCONNECTION.

NOTE:  THERMOSTAT DOES NOT PROVIDE MINIMUM OFF TIME IN             
              HEATING.

FAN 
OPERATION
SWITCH

2

3

1

SUBBASE 
LOGIC/ 
CONTROL 
CIRCUIT

4

3

4

POWER
SUPPLY

THERMOSTAT 
LOGIC CIRCUIT

Refer to Figs. 8-14 for typical hookups of subbase and

thermostat.

To customize the thermostat cycling performance to

various types of heating equipment, cycle rate adjustment
screws are provided on the back of the thermostat to
provide optimum room temperature control.

NOTE: Most applications will not require a change in

cycle rate.

The room air temperature will normally vary slightly

from the comfort temperature setting with the cycling of
the fur-nace or air conditioner.

The cooling cycle rate is factory-set and cannot be

adjusted. The heating cycle rate can be adjusted by turning
one or both cycle rate adjustment screws located on the
back of the thermostat. In multistage heat systems, the
cycle rate adjustment applies to the highest stage of heat
only. Screws should be backed out about one-half to one
turn, or be turned in until tight. See Fig. 15.