Emerson E2 Manual do Operador descarregar pdf (Página 49)

Intelligent Store™ Discus® Compressors are lower

than for standard demand cooling compressors. This

is to compensate for the probe location used on the

Intelligent Store™ Discus®. The actual peak gas

temperatures inside the head are correspondingly

higher and will be at the standard demand cooling

levels during injection start, injection stop and at the

maximum trip temperature.

The following demand cooling service procedures are

covered below:

• Manually triggering injection

• Temperature probe inspection

• Coil inspection and replacement

• Injection valve replacement

5.1.1 Manually Triggering Injection

Injection may be forced for diagnostic purposes only,

by sending a signal to the module that the probe

temperature is above the “Injection Start” tempera-

ture. The probe is an NTC (Negative Temperature

Coefficient) unit meaning that its resistance decreas-

es with increasing temperature. Unplugging the

temperature probe from the harness and holding a

jumper across the harness connector will signal the

module to load the coil, if the compressor is running.

Caution: Inserting an oversize wire into the connector

will “spring” open the female connector terminals,

impairing their function. See figure 5.3 below for a

view of a jumpered harness.

Figure 5.3 Jumpered Temperature Input on Harness

5.1.2 Temperature Probe Inspection

Erroneous temperature probe readings are often due

to “sprung” connections at the harness, or corrosion

on the harness connector surfaces. A reading of

approximately -40F is indicative of an open circuit or

poor electrical connection. Unplug the temperature

probe from the harness and measure the probe resist-

ance to determine whether the probe itself is faulty.

Refer to figure 5.4.

Figure 5.4 Temperature Probe Resistance

Plug the connector back in and look at the head

temperature for this compressor on the E2 screen.

Agreement between the calculated probe tempera-

ture based on resistance and the E2 temperature indi-

cate the harness connection is good. An extreme tem-

perature indicates the probe is faulty.

A probe temperature based on resistance that seems

reasonable based on the approximate temperature of

the head indicates the probe itself is not faulty. If the

E2 shows a head temperature that is obviously not

correct, visually inspect the harness connector to look

for signs of corrosion or for “sprung” female terminals

in the harness. If the terminals appear to be “sprung”,

carefully squeezing the outside of the plug to recon-

figure their shape may yield acceptable contact.

Nyogel 760G lubricating grease is used in the

connector to prevent fretting and corrosion.

Jumper Wire

Thermometer

Temp. (F°)

Calculated Sensor

Resistance (Ohms)

60.8

62.6

64.4

66.2

69.8

71.6

73.4

75.2

78.8

80.6

82.4

84.2

87.8

89.6

91.4

93.2

96.8

98.6

100.4

102.2

104

105.8

107.6

109.4

141426

135000

128907

123129

117639

112437

107478

102762

98289

94041

90000

86139

82476

78984

75663

72504

69480

66609

63864

61254

58770

56394

54126

51966

49914

47943

46053

44262

42543

AE8-1337 R1

1 2 ... 44 45 46 47 48 49 50 51 52 53 54 ... 70 71

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Emerson E2 Manual do Operador Página 49

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