Service Air

Question 1

What is the Purpose of Service Air?

Answer 1

Provide oil free air to:
Breathing Manifolds
Mixing and agitating functions
Emergency backup to instrument air

Question 2

What is the normal configuration of the U2 to U3 Service Air Cross Tie?

Answer 2

Normally open, acts as “Station Air”

Question 3

What is the normal pressure of the U2/U3 Service Air Header?

Answer 3

100-110psig

Question 4

What are the normal setpoints for /configuration for the U1 to U2 Service Air Crosstie?

Answer 4

There is a pressure control valve that is normally isolated and msut be valved in.
When in service, the valve starts to open at 74psig sensed on U1 side.
Full open at 90psig (closes in reverse order/setpoints, no deadband)
Protects U2 from depressurizing

Question 5

Where are the U2/U3 Service Air Crosstie Valves? which are proceduralized?

Answer 5

There are 2
One south of SBGT - This is proceduralized
One by resin transfer A/C’s - not proceduralized

Question 6

How does the Service Air to IA Crosstie function?

Answer 6

Air operated
When IA main receiver pressure drops to 85PSIG, solenoid operated valve opens and applies main receiver pressure to air operator and opens valve

Question 7

What is the reset for the SA to IA cross tie?

Answer 7

When IA main receiver pressure above 87psig, manual reset by pushbutton near main receiver

Question 8

Where does the SA - IA Crosstie tap into IA sysem?

Answer 8

Before IA Prefilters

Question 9

What is the power source for the Service Air Compressor?

Answer 9

Div II 480 Bus - Bus 26(36)

Question 10

What are the set points for the Service Air Receiver to “load” / “unload”?

Answer 10

When main receiver drops to 100psig, first stage butterfly valve opens to allow outside air to enter compressor.
When main receiver pressure reaches 110psig, first stage butterfly valve closes and the intake path is blocked.

Question 11

What is the cooling for the Service Air Compressors?

Answer 11

TBCCW

Question 12

What is the purpose of the Service Air Compressors Carbon Monoxide Monitors? Where are they?

Answer 12

They detect CO2 likely from ehicle idling in TB Trackway or DG exhaust leak - 
ALarm at 35ppm local alarm andMCR alarm
U1 on west wall opposite U1 SAC
U2 on South wall behind near U2 SAC
U3 is near U3 SAC

Question 13

What MCR indications are there for teh Service Air System?

Answer 13

U2 and U3 SAC ammeter
U2 Service Air Header Pressure (No U3)
U2 and U3 Lo SA Pressure Alarm

Question 14

Who is allowed to authorize the U2/U3 SA Crosstie?

All of the others?

Answer 14

Unit Sup can authorize U2/U3 SA Crosstie

Shift Manager permission required for all other crossties

Question 15

What causes a SAC Trip?

Answer 15

First Stage Outlet Air Tem >425F
Second Stage Outlet Air Tem >425F
Second Stage Inlet Air Temp >145F
Lo Oil Pressure <20psig
Hi Oil Temp >175F