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HVAC Training

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Title:

Chiller Maintenance

Lesson Plan

NMH30C000105

EO: 1. 7

Discuss the process of inspecting and replacing the refrigerant PSV's

Introduction

In this objective the trainee will learn what to look for when inspecting the refrigerant pressure

safety relief valve and how to replace them.

Main Idea

Assess and address workplace hazards.

Verify the refrigerant has been transferred and the shell pumped down completely prior to

proceeding.

Use a back-up wrench for removal.

The inspection may be performed prior to pumping down the chiller.

1) All pressure vessels are required to have some type of pressure relief.

2) ASME specifications are stamped on the mac hi ne.

3) The pressure safety valves for the chillers should be inspected for signs of corrosion.

Note: The PSVs on the Essential chillers are replaced every 5 years. So no inspection is required. The Normal chillers

are inspected every year and replaced every 5 years.

a) Disconnect vent piping at valve outlet. (Union half and piping)

b) Inspect valve body and mechanism for any evidence of internal corrosion or foreign material

(rust,dirt,scale,etc.). W ha ts the w orst thing tha t could ha ppe n? Excessive rusting of the PSV could cause a

catastrophic leak of refrigerant which could then cause the tubs to rupture.

c) Verify PSVs and piping are free of foreign material.

d) The normal chillers have pipe elbow installed on the outlet to prevent rain from entering the valve and rusting

out the disc.

e) Reinstall vent piping.

4) When replacing the valves ensure that the pressure rating of the valve being installed matches the vessel.

a) Pressure rating of the cooler PSV's.

i) 2 on the Essential chiller at 185 psig

ii) 3 on the Normal chiller A,B,C at 185 psig

iii) 2 on the Normal chiller E02 at 185 psig

b) Pressure rating of the storage tank.

i) 2 on the Essential chiller at 285 psig

ii) 2 on the Normal chiller A,B,C at 285 psig

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Carrier 19FA Istruzioni per gli Interventi Pagina 40