| Tweet |
Custom Search
|
|
|
||
 TM 55-1905-219-14-8
4-31. STRAINER - AIR CONDITIONING - MAINTENANCE INSTRUCTIONS.
a. Refrigerant-12 acts as a cleanser, loosening particles of dirt and scale which will collect in the strainers.
Clean liquid line strainers soon after a plant is placed in operation and, after that, as often as required. Dirty
liquid line strainer screens will throttle and cause some expansion, so that a difference in temperature on either
side of a strainer indicates a stoppage and the need for cleaning.
b. To remove and clean a liquid line strainer screen, first pump down strainer. Close cut-out valve on inlet
side of strainer and allow plant to pump down. As pressure is reduced, the strainer will become cold and then
begin to warm up as soon as liquid refrigerant has been removed. At that time, close cut-out valve on outlet
side of strainer, that is, downstream of thermal expansion valve. (The automatic control valves, expansion and
solenoid, have also been isolated and can be disassembled for cleaning, repair or replacement as required.)
c. Remove flange strainer cover and strainer screen. Plug strainer to exclude air and moisture. Clean
screen thoroughly and reinstall leaving flanged cover partly disconnected. Slightly open cut-out valves on both
sides of strainer one at a time and allow a small quantity of refrigerant to blow the air out of the line. Then
quickly tighten strainer cover. Open cut-out valves to place strainer and automatic control valves back on the
line.
NOTE
When strainer and automatic control valves are
isolated for service, liquid refrigerant flow to
circuit may be continued by opening hand expansion
valve in bypass line. Crack hand expansion valves
open gradually (about 1/4-turn at a time) and not
too much to avoid flooding.
4-922
|
||
|
||
