Thermal energy storage tank annual maintenance checklist

Insulation and vapor seal inspected and repaired

Jacket opened where suspect, insulation dry to the core, vapor seal continuous and repaired at any breach, no hidden corrosion under the insulation.

Confined-space permit and attendant in place before any entry

Where the tank is entered, the site's permit-required confined-space program is followed: atmosphere tested, attendant posted and rescue ready before anyone goes in.

Tank pumps and valves locked out before any entry or draining

Every pump and valve that can move water into the tank locked and tagged. Entrant out, hatches shut and locks removed by whoever hung them before the cycle test.

Access hatches, gaskets and fixed ladders inspected

Hatch hinges, latches and gaskets sound and sealing, fixed ladders and platforms secure and free of corrosion, beyond the quarterly check that hatches are shut.

Storage water sampled and treatment confirmed

Water sampled and checked against the manufacturer's guidance, treatment confirmed, no scale, sediment or biological growth in the sample, results logged.

Internal diffusers and connections inspected where accessible

Diffusers or distribution headers clear of debris, no blockage that would short-circuit the thermocline, internal connections sound where they can be reached.

Glycol loop sampled for lab analysis

On ice systems, a loop sample sent for concentration, inhibitor level and pH, going beyond the quarterly refractometer reading, with results logged.

Tank water tested for glycol from a coil leak

On ice-on-coil tanks with glycol in the coils, the tank water is checked for glycol, since any trace points to a leaking coil or header.

Tank sensors compared with a calibrated reference at each height

Each tank sensor compared with a calibrated reference at the same point, offsets recorded, and any sensor outside the manufacturer's tolerance adjusted or tagged.

Level or ice inventory sensor checked against a manual measurement

Tank level measured by hand or sight tube and compared with the transmitter or inventory sensor reading, error recorded against last year's check.

High and low level alarms tested through to the BAS

Where the tank has level alarms, each is simulated and seen arriving at the BAS with the right point name, then cleared and returned to normal.

Charge and discharge set points compared with the design sequence

Schedule, end-of-charge limit and discharge set points at the BAS match the design sequence and commissioning record, with any change since explained.

Full charge and discharge cycle run and capacity confirmed

Tank driven through a complete charge and discharge, temperatures and level tracking as expected, usable capacity confirmed against the design and logged.

Tank returned to automatic charge and discharge control

Valves and pumps back in automatic, hatches closed and locked, jacket repairs closed up, and the tank left on its normal schedule for the next charge.

Capacity result and findings reported to the owner

Usable capacity against design, water and glycol results, sensor offsets and repairs made or still needed reported to the owner as next year's baseline.