1. DECAM LN2 PUMP REMOVAL - CHECKLIST
Its assumed that the LN2 inside has been purged from the tank and it is empty and electrically ready to be disconnected. Pressure and VI readouts OK, power disconnected. Check the dome rotation is free to move. All tools were collected and crew steps are defined. The following describes the mechanical equipment required to remove the tank from the roof, the tank top vessel and the cryo coolers head if required.

2. DECAM LN2 PUMP REMOVAL - CHECKLIST
[ ] DES/HEXAPOD LIFTING FIXTURE: 57 kg mass, with eyebolts locked 390mm from center . Note the jib hook does not fit in the upper eyebolt, a large shackle is need there (increasing headroom requirement) [ ] x3 flat slings, 5 feet (yellow) . Longer TelOps slings (purples) will result in not enough headroom clearance to 3ton jib at console roof, Add suitable x6 shackles

3. DECAM LN2 PUMP REMOVAL - CHECKLIST
Disconnect: [ ] Cryo coolers #1 & #2, Supply/Return lines. (x4) (use 1-5/8 wrenches) . Install clean caps in each open-end. [ ] x2 instrumentation probes(15/16w) [ ] Pressure probe at the tank neck (5/8w) [ ] Regulated pressure line (1-3/ /8 w) Cover open ends with bags to avoid dust contamination [ ] x2 Electrical RTD wiring & boxes Note: Tie down the connectors, to avoid snagging while lifting

4. DECAM LN2 PUMP REMOVAL - CHECKLIST
Disconnect: [ ]x2 supply/return lines to valve-box 1 step ) Vacuum jacket Use 13mm ratchet wrenches and nut drivers (no room). Lock bellows with cable ties while loosening the inner LN2 line

5. DECAM LN2 PUMP REMOVAL - CHECKLIST
Disconnect: [ ]x2 supply/return lines to valve-box 2 step) LN2 lines Use 1-5/8 & 1-3/4 wrenches to loose the connection (delicate fine thread) Avoid retainer and gasket to fall down into the jacket. Use full-round, captive gasket , not open-end type (open type is quite hard to install) Model: ref HyLok Gasket retainer 1” H-ZGRT-16 NI

6. DECAM LN2 PUMP REMOVAL - CHECKLIST
[ ] Disconnect x3 tank/roof bolts, two 1.5” wrenches [ ] Remove west fence at the roof, 3/8 bolts plates ( 9/16in wrenches)

7. DECAM LN2 PUMP REMOVAL - CHECKLIST
[ ] Connect the lifting fixture to the tank eyebolts and lift unit LESS than ½ inch. There is an interference with the valve box legs. Move tank to south and overtake the leg. Place tank on C floor and secure the equipment

8. DECAM LN2 PUMP REMOVAL - CHECKLIST
Top Vessel / Pump removal [ ] Remove top vessel bolts, (1-7/16w). Note #11 is installed upside down [ ] Locate and install x3 eyebolts on positions #2, 6 & 10. Install eyebolt plate between the flanges. Mark the position and alignment of the tank gasket before lifting.

9. DECAM LN2 PUMP REMOVAL - CHECKLIST
Top Vessel / Pump removal [ ] Use cryo-gloves during the removal operation. [ ] The weight of this unit is not aligned with the tank axis. Cryo-coolers heavy mass displaces CG towards eyebolt #10. Watch this while lifting the unit as the structure could suddenly tip and the pump is out of tank free-way up.

10. DECAM LN2 PUMP REMOVAL - CHECKLIST
Top Vessel / Pump removal – Top vessel rigging, marking gasket [ ] Use foam or a belt-hoist to avoid the #10 eyebolt sling damage the cryo-coolers

11. DECAM LN2 PUMP REMOVAL - CHECKLIST
[ ] Lift unit slowly . Separation plates in the structure obstructs the off-of-axis pump visualization. [ ] Unit could tip due to displaced weight. Keep area clear. [ ] Avoid smash the electronic connectors inside the tank.

12. DECAM LN2 PUMP REMOVAL - CHECKLIST
[ ] Remove the pump loosening x4 bolts. (14mm wrenches) [ ] Position of the pump bolts affects the installation /removal of the unit due to obstructions with the tank Mark the position before start operation.

13. DECAM LN2 PUMP REMOVAL - CHECKLIST
Old Pump issues: Heavy wear in bearings causes the shaft to settle down and impeller gets damaged