ASHRAE Handbook — HVAC Systems and Equipment, Valves

ASHRAE Handbook — HVAC Systems and Equipment, Cooling Towers

The basin heater thermostat has failed, not activating the heater in freezing conditions. Without basin heat, water in the sump and exposed piping will freeze, cracking the basin and potentially rupturing condenser water piping. Basin heaters must be verified annually before cold weather.

ASHRAE Handbook — HVAC Systems and Equipment, Heat Exchangers

Heavy scale buildup on heat exchanger plates indicates failed water treatment. Fouling reduces heat transfer efficiency and increases pressure drop across the exchanger. Scale deposits as thin as 1/32" can reduce heat transfer by 25%. The plates must be cleaned with an approved chemical descaler and water treatment program corrected.

ASHRAE Handbook — HVAC Systems and Equipment, Primary-Secondary Pumping

The decoupler (bridge) pipe must be sized to match the largest system pipe — in this case 10". An undersized decoupler creates excessive pressure drop between primary and secondary loops, causing flow interference and unpredictable delta-T performance.

ASHRAE Standard 188 — Legionellosis: Risk Management for Building Water Systems

Conductivity of 4,500 µS/cm is nearly double the upper target limit, confirming excessive mineral concentration. High conductivity accelerates scale formation, promotes corrosion, and creates conditions favorable for Legionella growth. Immediate blowdown is needed to reduce conductivity to target range.

ASHRAE TC 9.9 / TIA-942 5.3.5

Cables routed across perforated floor tiles obstruct cold air delivery to server inlets. Under-floor cable routing must maintain clear pathways around perforated tiles. Cable obstruction can reduce tile airflow by 50% or more.

ASHRAE TC 9.9 / TIA-942 Annex G

Propping open hot aisle containment doors defeats the purpose of airflow separation. Containment doors must remain closed and self-closing to maintain the pressure differential between hot and cold aisles.