Summer Cooling Readiness Checklist: Chillers, Towers, Absorbers

This checklist is for people responsible for keeping production running: production managers, chief engineers, energy managers and operations teams. You can hand it to a service crew as a working document. Most summer breakdowns of cooling equipment are not real failures but small issues that piled up over winter and surface under load. They can be seen in advance, and almost all of them are fixed by planned preparation 4 to 6 weeks before sustained hot weather. It is based on our log of deviations for 2021 to 2025 (337 documented cases) and on ASHRAE, CTI and EPA industry practice adapted to Russian codes. The PDF is in Russian; the key points are below in English.

What is inside the checklist?

• Why summer breaks cooling systems, with figures on losses from fouling and scale.

• A one-page summary: the three main actions and a countdown schedule to the heat.

• Chiller checklist: air-cooled and water-cooled condenser, refrigerant circuit, water and glycol, electrics and controls, key readings.

• Cooling tower checklist: mechanics and drive, fill and drift eliminators, water treatment and Legionella prevention.

• Absorption chiller checklist: lithium bromide solution, vacuum, cooling water and heat source.

• A general checklist for managers: schedule, redundancy, people, documents, cost of downtime.

Key takeaways

In hot weather the capacity margin melts away. Equipment is selected for the design outdoor temperature per SP 131.13330.2020 (Russian building climatology code). The hotter it gets, the smaller the gap between refrigerant and outdoor air: condensing pressure and power draw rise, cooling capacity falls. If by then the condenser is clogged with poplar fluff and the cooling tower has scale, the machine cannot deliver its rated capacity and trips on high pressure.

Dirt costs you percent of capacity. A fouling layer of about 1 mm on an air-cooled condenser's fins cuts efficiency by up to 21% and raises the power draw of the refrigeration side by up to 35% (US EPA data). Scale of just 0.25 mm on the tubes of a water-cooled condenser cuts heat transfer by about 30%. Every extra degree of condenser approach adds 1 to 2% to power consumption. That is why cleaning heat exchange surfaces is the best-paying step in pre-season preparation.

Count down: 6, 4, 2 weeks. Prepare before temperatures settle above +25 °C, not in the first hot week, when service companies are swamped with calls and you can no longer shut machines down. Six weeks out: plan, assign owners and order spares (filters, screens, belts, nozzles, refrigerant, glycol, chemicals). Four weeks out: maintenance by checklist while machines can still be taken offline one at a time. Two weeks out: a test under load on a hot day and a check of the standby machine.

Three actions cover most of the risk. Clean the chiller condensers and the cooling tower fill. Sort out the water: glycol in the chiller loop and recirculating water in the cooling tower, including disinfection against Legionella. Check electrics, drives and redundancy: terminals and seals, bearings and belts, and an actual start of the standby machine.

Moisture in terminal boxes is the main enemy of the electrics. In our deviation log it is the most frequent cause of short circuits and tripped breakers. Because of it we now treat every motor with potting compound and sealant at our plant. In our experience refrigerant leaks occur more often at site-installed joints than in factory piping, so check the joints first.

Cooling towers: water and hygiene. Before the season the system is cleaned and shock-disinfected; the typical regime under ASHRAE 188 is 4 to 5 mg/l of free chlorine at pH 7.0 to 7.6 held for about 6 hours. Drift should be no more than 0.001% of the circulating flow (CTI practice); visible "rain" from the tower means a damaged drift eliminator. Approach to wet bulb is usually 3 to 5 °C; if it grows, the fill is fouled or airflow is short.

Absorption chillers: crystallisation and vacuum. Lithium bromide concentration is kept in the working range, typically about 54 to 64%; over-concentration near the crystallisation line is the main threat. Operating vacuum is on the order of below 10 mm Hg absolute, and air ingress sharply cuts capacity. The machine takes about 30 minutes to reach full output, so if it is critical for production, keep a tested standby for the peak heat.

N+1 redundancy has to start, not just exist on paper. Start the standby machine, write down what the shift does if a machine trips at peak heat, and work out what one hour of downtime costs. One avoided emergency shutdown at the height of the season almost always costs more than the whole pre-season programme for the entire fleet.

Who is it for?

• Chief engineers, energy managers and production managers before the season.

• Operations teams and service crews, as a working checklist with sign-off fields.

• Directors deciding how much to invest in preparation who want to see the risks and the money.

FAQ

When should summer preparation of cooling systems start?

Six weeks before temperatures settle above +25 °C: that is when you plan and order spares. Maintenance follows four weeks out, and a test under load plus a standby check two weeks out.

What should be done first if time is short?

Clean the heat exchange surfaces: chiller condensers and cooling tower fill. This brings back the capacity that dirt takes away, up to 21 to 35% on the condenser. Then the water in the loops and the electrics.

Why does a chiller trip on high pressure in summer?

On a fouled condenser, condensing pressure can rise, say, from 10 to 15 bar in the same weather. The high-pressure switch trips and the compressor stops, exactly when cooling is needed most.

Related articles

• How to cut industrial cooling costs: 8 measures with the numbers

• How much water does a cooling tower use, and how to cut make-up

• What is an absorption chiller? How it works, when it beats a chiller

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