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Oil Shortage (Low Oil Level)

Likely causes

Oil trapped in evaporator or piping due to poor trap design

Check: Verify oil specification (R22: mineral oil; R404A/R410A: POE oil)

What to do: Verify oil specification (R22: mineral oil; R404A/R410A: POE oil) → Check system pressure before adding oil (cannot add under high pressure) → Add correct oil through oil charging valve → After charging, confirm oil level in sight glass (1/4–3/4 range) → Review pipe trap design for oil return bends → Check oil separator presence and function

Oil return line blocked

Check: Check system pressure before adding oil (cannot add under high pressure)

What to do: Check system pressure before adding oil (cannot add under high pressure) → Add correct oil through oil charging valve → After charging, confirm oil level in sight glass (1/4–3/4 range) → Review pipe trap design for oil return bends → Check oil separator presence and function

Oil separator malfunction

Check: Add correct oil through oil charging valve

What to do: Add correct oil through oil charging valve → After charging, confirm oil level in sight glass (1/4–3/4 range) → Review pipe trap design for oil return bends → Check oil separator presence and function

Field tip

Oil level is low. Identify cause (oil trapped in pipework or oil leak) and add refrigeration oil of correct specification. Wrong oil type causes sludge, capillary blockage, and compressor burnout. Always verify the oil spec before adding.

All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.

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