York W)036 THRU 060 Specifications download pdf (Page 44)

542300-YIM-A-1009

44 Johnson Controls Unitary Products

Compressor Protection

In addition to the external pressure switches, the compressor

also has inherent (internal) protection. If there is an abnormal

temperature rise in a compressor, the protector will open to shut

down the compressor. The UCB incorporates features to

minimize compressor wear and damage. An Anti-Short Cycle

Delay (ASCD) is utilized to prevent operation of a compressor

too soon after its previous run. Additionally, a minimum run time

is imposed any time a compressor is energized.

The ASCD is initiated on unit start-up and on any compressor

reset or lock-out.

Flash Codes

The UCB will initiate a flash code associated with errors within

the system. Refer to UNIT CONTROL BOARD FLASH CODES

Table 25.

Reset

Remove the call for cooling, by raising thermostat setting higher

than the conditioned space temperature. This resets any

pressure or freezestat flash codes.

Electric Heating Sequence Of Operations

The following sequence describes the operation of the electric

heat section.

Single-stage heating (applies only to 5, 7 & 10 kW 230V

heaters and to 7, 10, & 15 kW 460V and 575V heaters. All other

heaters MUST use a two-stage thermostat):

a. Upon a call for heat by the thermostat, the heater

sequencer (1S) will be energized. After completing the

specified fan on delay for heating, the UCB will energize

the blower motor.

b The thermostat will cycle the electric heat to satisfy the

heating requirements of the conditioned space.

Two-stage heating (applies only to 15, 20 and 30 kW 230V

heaters and 20 and 30 kW heater 460V and 575V heaters.):

a. Upon a call for first-stage heat by the thermostat, the

heater sequencer (1S) (15, 20, 30 kW 230 volt) and

contactor (2M) (20, 30 kW 460 and 575 volt) will be

energized. After completing the specified fan on delay for

heating, the UCB will energize the blower motor.

If the second stage of heat is required, heater sequencer

(2S) (12, 20, 30 kW 230 volt) or contactor (3M) (20, 30 kW

460 and 575 volt) will be energized. After completing the

specified fan on delay for heating, the UCB will energize

the blower motor.

b The thermostat will cycle the electric heat to satisfy the

heating requirements of the conditioned space.

Electric Heat Operation Errors

Temperature Limit

If the UCB senses zero volts from the high temperature limit,

the indoor blower motor is immediately energized.

This limit is monitored regardless of unit operation status, i.e.

the limit is monitored at all times.

If the temperature limit opens three times within one hour, it will

lock-on the indoor blower motor and a flash code is initiated

(See Table 25).

Safety Controls

The UCB monitors the temperature limit switch of electric heat

units.

The control circuit includes the following safety controls:

Temperature Limit Switch (TLs)

This control is located inside the heater compartment and is set

to open at the temperature indicated in the Electric Heat Limit

Setting Table 19. It resets automatically. The limit switch

operates when a high temperature condition, caused by

inadequate supply air flow occurs, thus shutting down the

heater and energizing the blower.

Flash Codes

The UCB will initiate a flash code associated with errors within

the system. Refer to UNIT CONTROL BOARD FLASH CODES

Table 25.

Reset

Remove the call for heating by lowering the thermostat setting

lower than the conditioned space temperature.This resets any

flash codes.

Table 19: Electric Heat Limit Setting

Voltage kW

Temperature Limit

Switch

Open Temperature

°F

208-1-60

5 1 140

71,3 140

10 1,2,3 140

15 2,4,6 140

1,2,3,4,5 140

6 150

30 1,2,3,4,5,6 150

230-3-60

51,2,3 140

71,2,3 140

10 1,2,3 150

15 2,4,6 140

20 1,2,3,4,5,6 150

1,3,5 160

2,4,6 150

460-3-60

7 2,4,6 140

10 2,4,6 140

15 2,4,6 140

20 3 160

30 3 150

575-3-60

10 2,4,6 140

15 2,4,6 140

20 5 160

30 5 150

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York W)036 THRU 060 Specifications Page 44

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