Electronic Defrost Control (Edc) - GE HPS15BTHR Technical Service Manual

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Table Of Contents

Table of Contents

The EDC processes

1. The amount of time the compressor has run.

2. The number of times the fresh food door was open.

3. The length of time the defrost heater was on.

During the defrost mode, the electronic control monitors the defrost heater operation (heater ON time). Once

the heater operation is terminated by the Defrost Thermostat, the electronic control will allow a DWELL TIME

before initiating the next cooling cycle. Dwell time is the elapsed time from the heater termination until the

cooling operation is resumed (approximately 15 minutes). If the Defrost Heater remains on more than 25

minutes (or a maximum of 40 minutes), the EDC board will go directly into the cooling mode and bypass the

DWELL TIME MODE. This cycle would be considered an Abnormal Defrost.

During the cooling operation, the electronic control monitors door opening times and compressor run times.

These times are measured in seconds (1 second of door opening = 286 seconds) and are accumulated until

they add up to 80 hours of total equivalent compressor run time. One door opening at 1 second X 286, is

equivalent to 4 minutes 46 seconds of compressor run time.

Once 80 hours (4600 minutes) of total equivalent compressor run time is reached, the refrigerator will enter

the Defrost Mode. The total equivalent compressor run time is calculated by multiplying the accumulated

amount of time the Fresh Food door was open since the last defrost cycle by a multiplication factor, then

adding to that number the actual amount of time the compressor has been running since the last defrost

cycle.

The MULTIPLICATION FACTOR of 286 seconds is used to compute an equivalent compressor run time for each

time the refrigerator (Fresh Food door) door is open. For example, with a multiplication factor of 286 and a

door open 10 times for one second each time, 2860 seconds of equivalent compressor run time is noted,

(286 X 10). NOTE: To get door opening seconds to minutes, divide the total number of door opening seconds

by 60 (60 seconds = 1 minute). Example: 10 x 286 = 2860 seconds, 2860 / 60 = 47 minutes.

(

Accumulated door open

time (door openings)

To initiate manual defrost, open the fresh food door, then press the door switch located on the control

panel three (3) times within five (5) seconds and close the fresh food door. Pressing this switch in this way

will initiate an immediate defrost unless the control is already in the Defrost or Dwell states. After defrost

is initiated, the normal defrost sequence will follow and the normal rules will determine the start of the

next defrost. NOTE: If the refrigerator has been unplugged, wait 45 seconds before initiating the defrost

diagnostic.

To terminate defrost, with the fresh food door open press the door switch three (3) times within five (5)

seconds when the control is in either the Defrost or Dwell states. Pressing this switch in this way will

terminate the defrost and initiate a first cycle state (time starts at 0).