R-Pro › Field cases › Air conditioning
AC New Install — Refrigerant Line Insulation and Condensation Prevention
Likely causes
Step 1 — Select insulation thickness and verify material spec (ASHRAE 90.1)
Check: Minimum thickness: 1/2 inch (12.7 mm) — residential standard (ASHRAE 90.1). Outdoor or hot/humid = 3/4 inch (19 mm)+. Material: closed-cell foam — elastomer (NBR/EPDM) or nitrile rubber. ASTM C534 compliant. UV-exposed runs require UV-resistant grade.
What to do: Insulate both liquid (small tube) and gas (large tube) lines. Gas (suction) line has higher condensation risk. Slide insulation onto tube before flaring — retrofit-fit damages and creates joint leaks. At joints: elastomer-compatible adhesive + maintain consistent thickness.
Visible condensation = symptom of insulation failure. Identify location and re-do — leaving it causes ceiling rot, mold, customer disputes. Outdoor insulation degrades within 5 years under sun — use UV-resistant grade or aluminum jacket. Glue and tape every joint.
All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.
Open R-Pro →