Coolroom Installation Problems – Common Mistakes, Causes & How to Prevent Them

Choosing the Wrong Coolroom Size

Coolroom sizing is not simply a question of fitting the biggest room possible into the available space. The installer needs to understand what will be stored, how much stock will be inside, how employees will access it and how air will circulate once shelving is installed.

A room that is too small can quickly become overcrowded, forcing stock directly beneath the evaporator, blocking return airflow, and obstructing doorway circulation. Conversely, an unnecessarily large room increases surface area heat gain and energy costs.

Key Factors to Sizing: Normal and peak stock volume, shelving configuration, trolley/pallet access, product pull-down requirements, delivery frequency, and door-opening patterns.

Installing the Coolroom on an Unsuitable Base

The floor or slab beneath the coolroom affects the alignment of everything built above it. If the installation surface is significantly uneven, assembling the room square and plumb becomes difficult.

Potential Consequences: Door frame racking, uneven gasket compression, joint separation, and drainage flow issues. The supporting slab must be checked for level, moisture barriers, and load-bearing capacity prior to panel assembly.

Using the Wrong Floor Design

A chilled coolroom (+2°C to +4°C) and a freezer room (-18°C to -22°C) require fundamentally different floor construction.

Freezer Rooms: Sustained sub-zero operation requires dedicated underfloor insulation, vapour barriers, and thermal breaks. Without appropriate substrate protection, continuous cold migration into the concrete slab causes subfloor moisture to freeze, expand, and crack the slab (frost heave).

Poor Drainage Planning

Water issues in coolrooms are frequently drainage design errors rather than refrigeration machinery breakdowns:

• Evaporator Condensate Drainage: Must have adequate fall (gradient), short runs, and drain line heaters in freezer applications to prevent ice blockages.
• Wash-Down Drainage: Floors must feature graded falls toward floor wastes to prevent pooling water and biological contamination.

Incorrect Refrigeration-System Sizing

Cooling capacity must be calculated using full heat-load calculations rather than room volume alone. Heat load factors include ambient outdoor extremes, daily door-opening frequency, warm incoming product mass, lighting, fan motors, and internal occupancy.

Undersized Systems: Run continuously, lose temperature during deliveries, and struggle on 35°C+ summer days. Oversized Systems: Short-cycle, fail to dehumidify properly, and cause premature component wear.

Installing the Condenser Where It Cannot Reject Heat

The condensing unit rejects all extracted room heat into the surrounding atmosphere. Locating condensers in unventilated plant rooms, cramped ceiling voids, or tight corners causes hot-air recirculation.

This elevates head pressure, triggers high-pressure safety trips, cuts cooling capacity, and accelerates compressor burnout.

Poor Evaporator Position and Air Distribution

Cold air must reach every corner of the storage space. If the evaporator blows directly into high shelving or return air is blocked by stock, airflow short-circuits back into the unit.

This causes the temperature sensor near the coil to satisfy and cycle off while stock at the far end remains dangerously warm.

Poor Door Position, Alignment or Selection

The doorway is the primary point of thermal and humidity infiltration. Installing door frames out of square prevents magnetic gaskets from compressing evenly, allowing humid air to enter continuously.

This creates doorway ice accumulation, sweating walls, and extended compressor run times.

Poorly Planned Refrigeration, Drain and Electrical Services

Uncoordinated service penetrations create thermal bridges and air leaks. Every pipe, conduit, and drain penetrating the insulated wall must be detailed with vapour-sealed escutcheons and closed-cell foam insulation.

Installing the Temperature Sensor in the Wrong Position

A sensor mounted directly in the cold discharge air stream registers a false low reading, shutting off the system before the room cools. Placing it too close to the door registers false high readings, overworking the compressor. Sensors must sit in representative return-air zones.

Incorrect Defrost Setup

Inadequate defrost frequency or short durations allow ice to encase evaporator coils, blocking airflow. Excessive defrosting adds unnecessary thermal load to the room. Defrost termination sensors and fan delay timers must be calibrated to room humidity.

Poor Electrical Planning

Failing to establish total connected electrical loads (compressor, fans, defrost heaters, drain heaters, door frame heaters, controllers) leads to nuisance breaker trips and voltage drops that damage compressor motor windings.

Unsupported Equipment and Poor Ceiling Planning

Insulated sandwich ceiling panels are not structural load-bearing floors. Heavy commercial evaporators, pipe runs, and cable trays require independent suspension hangers tied into the building’s primary structural steelwork.

Forgetting Future Maintenance Access

Refrigeration systems require routine maintenance. Installing condensing units or evaporators hard against walls prevents technicians from cleaning coils, replacing fan motors, or servicing expansion valves without expensive dismantling.

Treating Commissioning as "Switch It On and See If It Gets Cold"

Proper commissioning requires systematic pressure testing, deep vacuum evacuation (below 500 microns), precise refrigerant charging by weight, superheat/subcooling measurements, and a supervised pull-down temperature test under load.

Assuming a DIY Cooling System Equals Commercial Refrigeration

Converting domestic air conditioners with external controllers (e.g. CoolBot) has strict limitations. They are not engineered for sub-zero freezer use, have limited humidity extraction, struggle during frequent commercial door traffic, and lack the robust continuous-duty ratings of commercial refrigeration plants.