Carrier 69NT40-521, 69NT40-511-199 manual Step, Yes

STEP

A

Compressor Starting Sequence

*Operating capacity is the required capacity to maintain container box temperature.

**Required voltage is a function of operating capacity and supply frequency.

B

C

YES

D

E

F

G

H

I

J

L

Is Ambient

NO

Low Speed

Run For 2

Temperature Less

Soft Start

Minutes

Than 60 ˚F ?

(See Note A & B)

YES

YES

High Speed Start

Was Ambient Greater

Than 60 ˚F During Start ?

NO

Does High Pressure

YES

Is Supply Voltage

Switch (HPS) Trip ?

Greater Than

Required Voltage ** ?

NO

NO

NO

YES

Has Compressor Run

Are High Speed Switch

For 20 Minutes ?

Over Conditions Satisfied ?

(Refer To Steps “J & L”)

YES

NO

NO

Has Set Point

Continue In

Been Reached ?

Low Speed

YES

NO

Is The Operating Capacity *

Below Low Speed Capacity ?

YES

NOTE A

Is Supply Voltage

YES

During

compressor

Greater Than

Required Voltage ** ?

operation, if at anytime the

High Pressure Switch (HPS)

NO

trips, the logic will switch to

Low Speed

Low Speed Soft Start.

Soft Start (See Note B)

NOTE B

Low

Speed

Soft Start

is

performed

by closing

the

Run 20 Minutes

Continue In

SMV to 0% opening for ten

Low Speed

seconds during the start-up

of the compressor. The SMV

opening is

then gradually

Is Supply 3 ˚F Above Set Point

NO

increased to the desired value

Or Is Operating Capacity *

Greater Than Low Speed Capacity ?

at the rate of a 3% opening

per second.

YES

Figure 3-6. Two-Speed Compressor Speed Change Logic -- Perishable Range Only

T-268-07 3-36