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Chilled Water Glycol Concentration Fault (Freeze Risk)

Likely causes

Insufficient ethylene glycol concentration — below minimum 30%

Check: Measure concentration on-site with refractometer within 10 minutes — add glycol immediately if below 30%. Freeze point conversion: EG 30%→-16°C, 35%→-20°C, 40%→-24°C

What to do: Inject glycol concentrate directly to adjust concentration — design freeze point = region's lowest temperature minus 5°C safety margin. Re-measure with refractometer after top-up

Over-dilution from excess makeup water — concentration not readjusted after refilling

Check: Check leak history and verify refractometer measurement records after each makeup water addition. Measure on-site immediately if not in regular inspection records

What to do: Establish makeup water protocol: re-measure with refractometer immediately after top-up → add concentrate to correct if below target. Set concentration-linked control if automatic makeup system installed

Glycol degradation (oxidation) — pH below 7.0 or browning indicates increased corrosivity

Check: Measure pH on-site with pH strips or meter — replace or add corrosion inhibitor if pH outside 7.0–9.0 range. Visually inspect glycol for brown discoloration

What to do: Add corrosion inhibitor or fully replace solution if pH below 7.0. Before cold snap: maintain circulation pump at low speed before shutdown or activate electric freeze-protection heaters

Field tip

Refractometer is a must-have field tool. EG 30% = -16°C freeze point. Set 5°C below your region's lowest temperature. Re-measure every time you top up — unmeasured concentration is the main cause of freeze accidents.

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