2020 Tech Report Jan-Feb

Task # 2.b.: Cleaning a Strainer in a Configuration “B” Control Group: Gauge Valves

ACTION

COMMENT

CAUTION: Failure to properly secure the end of the hose in the water bucket can lead to the hose coming free, whipping around, and possibly causing injury to personnel nearby, as well as allowing ammonia vapor to escape to the atmosphere directly. CAUTION : Opening Valve “C” too fast or too far can cause water/ammonia mixture to splat- ter from bucket.

10.

Attach a suitable hose, approved for am- monia service, to Valve “C.” Terminate and secure the opposite end of the hose (currently attached to Valve “C”) in a bucket of water outside and downwind of the plant if possible.

11.

Slowly throttle open Valve “C.”

12.

When pressure has bled off, close Valve “C.”

13. 14.

Remove hose from Valve “C.”

Check for any remaining pressure by carefully opening Valve “C.” If any pres- sure exists as evidenced by strong am- monia odor, reattach the hose to Valve “C” and repeat pump out procedure (Steps 11 through 14) of this Maintenance Pro- cedure. Verify that the control group has been isolated and pumped out.

If pressure continues to exist, it may be neces- sary to repeat this task to ensure all valves are tightly closed. If the problem persists, inform your supervisor or facility contact.

NOTE: The control group should remain un- der Refrigeration Operator / Technician con- trol throughout this procedure. If not, the pos- sibility exists that conditions may have been altered after isolation, requiring the repetition of this Task.

15.

16.

Ensure that all ammonia refrigerant in the isolated section with the strainer is pumped out to 0 PSIG. Slowly remove the bottom cap of the strainer or filter, either unscrewing the hex bottom or loosening the cover bolts.

CAUTION: Be careful to avoid any refrigerant which may still be in the strainer or filter. See the strainer Manufacturer’s Operation and Maintenance Manual for instructions.

17.

NOTE: If the screen is damaged or debris / sludge / sediments cannot be removed and cleaned, replace the screen assembly.

18.

Slowly remove the screen / filter assem- bly and clean with a good solvent; blow dry and inspect.

RETA TECHNICAL REPORT PAGE 12