Liebert Notes

Question 1

A call for heat/cool is sent as input through the ________ which becomes an output (command)

Answer 1

microprocessor

Question 2

Lieberts use industry standard triacs rated at a ___amp capacity

Answer 2

2amp

Question 3

If a load is removed from the triac, you can get a false reading due to potential voltage. True or False?

Answer 3

True

Question 4

On a Liebert, the gate connects the ______-_______

Answer 4

opto-isolator

Question 5

The pin/dot on the opto-isolator represents?

Answer 5

Location of pin 1

Question 6

Input pin 1 is ___volts

Answer 6

AC (24v prior and 1.2v at opto)

Question 7

Output pin 1 is ___volts

Answer 7

DC (5vdc)

Question 8

Pin one is the voltage being received by the opto. True or False?

Answer 8

True

Question 9

Pin 2 on the input opto completes the AC source to ______/_______

Answer 9

neutral/ground

Question 10

Pin 2 on an output opto completes the DC source to ______-_______

Answer 10

digital-ground

Question 11

Input Opto has no voltage signal on what pins?

Answer 11

3,6

Question 12

Pin 4 and 5 on input opto?

Answer 12

Pin 4 completes DC source to digital ground.

Pin 5 receives Dc signal to microprocessor (5v when not activated and 0v when activated)

Question 13

Output opto has no voltage signal on what pins?

Answer 13

pin 3,5

Question 14

Pin 4 and 6 have what function on output opto?

Answer 14

Pin 4 completes 24Vac path to gate of the triac

Pin 6 receives AC source signal from input device

Question 15

Output Opto 1-2 pins are __v when conducting and __v when not conducting

Answer 15

0v

5v

Question 16

Purpose of the opto-isolator is to provide isolation of ___ voltage sources

Answer 16

two

Question 17

Opto-isolators allow a DC voltage to activate an AC load or allows an AC voltage source to provide a ____ signal

Answer 17

DC

Question 18

Two types of Opto isolators are?

Answer 18

Input and Output Opto

Question 19

Difference between input and output opto?

Answer 19

Input provides DC signal and Output allows DC source to activate an AC load

Question 20

The output-opto uses a DC source to activate a ____ internal to the IC chip. This causes a triac, also internal, to switch on allowing current flow to the AC load

Answer 20

LED

Question 21

What is the purpose of the ribbon cable on the leibert?

Answer 21

status and alarm lights

Question 22

When is the hot gas bypass coil energized?

Answer 22

When evap press temp is too low, HGBV opens and allows hot gas to mix with refrigerant

Question 23

Purpose of HGBV?

Answer 23

reduce cooling capacity and defrost coil

Question 24

Humidifier pan fills with water based on ?

Answer 24

time (9.5min for 40sec)

Question 25

The leibert filter clog is nuisance tripping. How to resolve?

Answer 25

disconnect the switch

Question 26

The Leibert requires water in the infrared humidifier pan. How to make this happen electrically?

Answer 26

Put factory jumper on Q12

Question 27

How is auto flush control accomplished on Leibert Level O?

Answer 27

Programming

Question 28

INput-optos isolate what voltages? a) AC voltage control of DC voltage b) DC control of AC voltage c) Are not used on Level O controls

Answer 28

a)

Question 29

Output-optos isolate what voltages? a) AC voltages control of DC voltage b) DC voltage control of AC voltage c) Are not used on Level O controls

Answer 29

b)

Question 30

What device activates the gate of the triacs?

Answer 30

OPTO

Question 31

What does EPROM stand for?

Answer 31

Erasable programmable read only memory

Question 32

What precaution must be taken when checking bulbs of infrared humidifier lamps?

Answer 32

do not look directly at bulbs

Question 33

What precaution must be taken when changing bulbs of infrared lamps?

Answer 33

Do not touch bulbs with bare hands

Question 34

What device will prevent Leibert from starting immediately when power is resumed after a power failure? what is the max delay?

Answer 34

Sequential auto restart 0-90sec