Evaporative Condenser Spray Nozzle Clogging — High Condensing Pressure

Question

Accepted Answer

Scale and algae buildup blocking nozzle orifices (1.5–3 mm) due to poor water treatment. Check: With spray pump running, visually verify uniform wetting at coil top. Any dry patch → inspect those nozzles. Remove nozzle and borescope orifice or do light-transmission test. Check header branch pressure — higher than normal = downstream blockage. What to do: 1) Remove all nozzles, soak in 10% citric acid for 30–60 min to dissolve scale 2) Remove algae with 100 ppm sodium hypochlorite wash 3) Measure orifice diameter with vernier — replace if >10% enlarged 4) Inspect/replace inline filter (100 mesh) before reassembly 5) Water management: conductivity <2000 μS/cm, hardness <150 ppm. Spray pump impeller wear causing spray pressure drop (below design 1.5–2.5 bar). Check: Measure header pressure — below design 1.5–2.5 bar confirms issue. Compare pump discharge pressure; drop >2 bar (after piping losses) suggests impeller issue. Disassemble: check impeller wear and casing ring clearance (typical limit ≤0.3 mm). What to do: 1) Replace impeller (OEM, SS316 or bronze) 2) Replace casing rings at same time 3) Inspect/replace mechanical seal 4) Re-align shaft with laser alignment tool 5) On commissioning, verify pressure/current in normal range and log baseline. Winter freezing cracking or misaligning some nozzles. Check: After winter restart, visually inspect nozzles for cracks. Metal nozzles show hairline cracks; plastic nozzles show white stress cracks. Check spray pattern — asymmetric means misalignment or crack. Verify last year's freeze-drain records. What to do: 1) Replace all cracked/damaged nozzles (match OEM spec) 2) Reset vertical/angle alignment to design spray angle 3) Winter measures: standardize complete drain-down, inspect basin heaters and trace heating 4) Automate basin heating when ambient <5°C 5) Ensure drain valves at low points of spray line. Algae growth in fill/packing increasing airflow resistance. Check: Visually check fill discoloration (green/brown slime). Measure pressure drop — >200% of clean baseline = replace. Water quality: pH, conductivity, bio count (bacteria/fungi). Check light exposure — direct sunlight on fill accelerates algae growth 5×. What to do: 1) Remove fill, high-pressure wash; replace if severe 2) Routine algaecide dosing: maintain 0.5–1 ppm chlorine + biweekly non-oxidizing 3) Install shade covers to block direct sunlight on fill 4) Rebalance blowdown/makeup to lower COC 5) Install 50 μm makeup water prefilter. Faulty water level control valve causing insufficient water supply → partial coil dry operation. Check: Measure basin level against float setpoint — deviation >5 cm indicates valve fault. Check makeup line flow meter. Manually actuate float valve to test open/close motion. For electronic level sensors, review low-level alarm logs. What to do: 1) Disassemble float valve: replace O-rings/seat, remove corrosion from linkage 2) Reset level setpoint (5 cm below overflow) 3) Replace/calibrate electronic sensor 4) Redundancy: float + electronic sensor recommended 5) Verify low-level alarm interlocks spray pump to protective stop. Inadequate blowdown raising chloride ion concentration → pitting corrosion on coils. Check: Measure cooling water conductivity — compare with design COC (concentration of cycles). Typical 3–5×. Measure chloride directly — >300 ppm = pitting risk. Section coil sample and inspect for pits (small surface holes). What to do: 1) Increase blowdown valve opening or install conductivity-based auto blowdown controller 2) Set target conductivity: makeup conductivity × COC target (typically 3–5) 3) For pitted coils, apply epoxy patch/tube sealing as interim, replace if severe 4) Long-term: dose corrosion inhibitor (tolyltriazole, polyphosphate) 5) Install corrosion coupons and verify corrosion rate <0.1 mm/year.

Evaporative Condenser Spray Nozzle Clogging — High Condensing Pressure

Likely causes

Scale and algae buildup blocking nozzle orifices (1.5–3 mm) due to poor water treatment

Spray pump impeller wear causing spray pressure drop (below design 1.5–2.5 bar)

Winter freezing cracking or misaligning some nozzles

Algae growth in fill/packing increasing airflow resistance

Faulty water level control valve causing insufficient water supply → partial coil dry operation

Inadequate blowdown raising chloride ion concentration → pitting corrosion on coils

Related cases