Carrier 19FA Instrukcje Operacyjne Pobierz pdf (Strona 20)

HVAC Training

Page : 20 of 42

Title:

Chiller Maintenance

Lesson Plan

NMH30C000105

3. If the refrigerant level remains out of range notify Operations, Engineering and HVAC for

additional direction.

The intent is to insure an accurate level is obtained prior to making an operability or corrective

action decision. However, operations is required to be notified and requested to run the chiller. At

this point a member of operations may decide to take a conservative approach and declare the

chiller in-operable until proven otherwise. This is always their option but is not the intent of the

task. To insure the intent of the steps is clear for the Control room staff, a pri 4 action has been

generated to enhance the existing statement in the task to state something to the effect; “Sight

glass level may not be and accurate indication of the chiller refrigerant charge due to stacking. The

following steps should be performed prior to determining necessary corrective actions or chiller

operability.”

Evaluation Conclusion

There words in the task are written as directed by CRDR 9-8-1324. The necessary steps to verify

level prior to making corrective action notifications are correctly identified in the instructions. The

STA made a conservative decision to declare the Chiller inoperable prior to performing these steps

and has every right to do so.

The discrepancy between the Operability level listed in the task and the 40OP are due to the

stand-by vs. operating conditions when the readings are required to be taken. The conditions

described in this CRDR were not the result of a Human Performance Error.

An action has been generated to enhance the recommendations to perform the steps necessary to

validate the sight glass level prior to determining operability.

I request this CRDR be closed based on the evaluation performed and the Note worthy HP Event

Criteria 5 requirements be removed.

Cause

Possible misunderstanding of how sight glass indications can change without loss of refrigerant

and that it should be validated prior to making an operability determination. If it was understood, a

conservative decision to declare the chiller in-op until proven otherwise is and will remain to be at

the discretion of the control room staff.

To insure the intent of the steps is clear for the Control room staff, a pri 4 action has been

generated to enhance the existing statement in the task to state something to the effect; “Sight

glass level may not be and accurate indication of the chiller refrigerant charge due to stacking. The

following steps should be performed prior to determining necessary corrective actions or chiller

operability.”

Evaluation Conclusion

The words in the task are written as directed by CRDR 9-8-1324. The necessary steps to verify

level prior to making corrective action notifications are correctly identified in the instructions. The

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Carrier 19FA Instrukcje Operacyjne Strona 20