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HVAC Training

Page : 14 of 42

Title:

Chiller Maintenance

Lesson Plan

NMH30C000105

Details of the event:

We have experienced problems with the lube oil heater temp controllers in the past. 200 °F has

been used as a "cut-off" temperature to evaluate whether lube oil lubrication ability could be

subject to premature breakdown.

The temperature controller (1JECATC0518) for the EC chiller oil sump heater has some history of

the set point drift. There has been several work orders issued to adjust the controller. A search of

SWMS found less than ten work orders that actually replaced a temperature controller.

On 08/04/02 a similar condition occurred on the Unit 1 "A" Chiller reference CRDR 2546696.The oil

temperature controller (1JEC ATC0517) was replaced.

Several CRDRs have been issued because of high lube oil sump temperatures. Operability

Determination # 94 was issued in 1996 to address the impact of high temperature on the EC lube

oil. The concern with high lube oil temperature is of a "long term" nature rather than an immediate

OPERABILITY concern.

This OD has been used several times over the years to justify operability of the chillers. The OD

has buffered the impact of finding the oil temperature outside of the normal temperature band.

The impact on plant operations has been minor for the majority of the times the temperature was

found outside of the normal control band. HVAC Maintenance has been able to replace the erratic

controller that fails to return to the normal control band. When the controller becomes intermittent,

like 1JECBTC0518, a work order written to replace the instrument as scheduled maintenance.

Fenwal temperature controllers are available on the market and the procurement lead time is

relatively short. A clearly declining trend has not been identified. There are no current plans to

replace the Fenwal controller with a different instrument because of performance problems.

CRDR # 2689093 documents an occurrence of low oil level which also caused low oil

temperature on 2MECBE01.

The description of the event:

On March 8, 2004 the Essential Chiller "B" was found with no visible oil level and oil temperature

out of specification low at 106 degrees. Minimum operability limit is 120 degrees.

Declared EC "B" INOPERABLE and complied with LCO 3.7.10.A. No visible oil leak was apparent

on the chiller skid. 1.5 gallons of oil was added to bring the level up to 3/4 of the lower sight glass

and the chiller was restored to OPER ABLE status at 0143 on March 9, 2004.

Details of the event:

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Carrier 19FA Betriebsanleitung Seite 14