An open multideck chiller keeps chilled product out in the open, with no door between the shopper and the shelf. The thing that holds the cold in is an air curtain: a moving sheet of refrigerated air that falls across the open front and separates the cold case from the warm sales floor. Because the curtain is invisible, store staff usually only think about it when something starts to go wrong — a shelf that feels warm, product at the front that is not holding, or water appearing at the base. This guide sets out what staff can actually observe about the air curtain before a service call, and what belongs in the note that reaches the technician.
The cabinet here is a multideck open chiller with an open front and no doors. That open front is the point of the design — product stays reachable — and it is also the part that depends on the air curtain working. A glass door upright cabinet closes its front with doors; an open chiller closes it with moving air. The two are different machines, and an air curtain check applies to the open cabinet only.
What the air curtain is and what it does
The air curtain is a continuous flow of cold air moving across the open front of the cabinet, from the discharge point at the top toward the return at the bottom. It works as a barrier: the chilled product sits behind a moving wall of air, and the curtain slows the warm, humid store air from rolling into the case. The colder the case runs relative to the store, the more work that barrier has to do, which is why an open chiller reacts visibly when the store is hot, humid, or draughty.
The curtain also depends on the path staying clear. Shelves, product, and trim all sit inside a designed airflow path, and anything that interrupts the flow — a shelf packed past its front edge, a high stack of product, or a display card taped into the airstream — weakens the barrier at that point. That interaction is why the air curtain check is not just about the top and bottom of the cabinet; it is about the whole open front.
What staff can see, and what they cannot
The air curtain itself is moving air, and staff cannot read its speed or direction the way they read a thermometer. What staff can see are the effects of the curtain on the things around it, and those effects are what the observation log records. A light strip of paper or a length of ribbon held near the open front shows whether air is moving and in which direction, without turning the check into a measurement. The point of that quick look is direction and presence — is the air moving down across the front, or does it stop partway down — not a figure to quote later.
What staff cannot see is the actual velocity or the volume of air the cabinet is supposed to move. Those are model-specific values held in the cabinet's own documentation, and the store leaves them to the technician rather than guessing at a number.
Visible signs that point at the air curtain
Several everyday signs suggest the curtain is struggling, and each one is an observation a shift member can make without tools:
- A shelf at the front of the case feels noticeably warmer than the shelves behind it, or warm air rolls out at shin height along the base.
- Product facing at the front of a shelf shows a different condition from product further back — softer packaging, moisture on the wrapper, or a warm feel on the label.
- Condensation sits on the front edge of shelves or on the front trim, where warm, humid air is meeting the cold front.
- A draught from a neighbouring door, a ceiling vent, or a till fan reaches the case front and visibly disturbs product or a test strip.
None of these signs names the cause on its own. They are the pattern the store records, and the technician interprets the pattern against the model's airflow design.
The load-line interaction
The air curtain and the product load are one system, and the clearest staff-side check is where product sits relative to the load line. Most open chillers carry a marked or documented load line — a shelf-front or case-front limit that product stays behind so the curtain can fall cleanly. When product is stacked above or forward of that line, it blocks the falling air, and the curtain weakens exactly where the stack sits.
The load-line discipline is covered in its own guide on open chiller product load lines and the shelf-front air path, and an air curtain check leans on it: the first thing staff look at when the front feels warm is whether anything has drifted past the line. A single overstacked shelf can produce the same symptom as a weak curtain, and clearing the stack is a merchandising fix, not a service call. The two checks run together, but they are separate records.
Reading the curtain during the day
The air curtain does not behave the same all day. It is most stressed when the store is warmest and the case is busiest — typically the middle of the day — and most settled in the cool of the early morning. An observation taken only in the quiet morning can miss a mid-afternoon drop, so the routine notes the time and the store conditions alongside the sign. A curtain that holds fine until a delivery door stands open, then warms the front row, is telling the store something about draughts around the case, not necessarily about the cabinet itself.
What the observation log records
An air curtain note is only useful when it names the situation rather than the suspicion. The entry records the cabinet, the date and time, the store conditions, the sign that was seen, and where along the case front it appeared. It also notes what was already checked — whether product was cleared back from the load line, whether a door or vent was open nearby — because that separates a merchandising cause from a cabinet cause before the technician arrives.
A note that says "front of the chiller feels warm" is a starting point; a note that says which shelves, which end of the run, what time, and what the load line looked like gives the technician a picture they can work from.
The service handoff
When the store does call service, the observation log is the handoff. The technician works from the pattern — warm front row, condensation on the front trim, a disturbance on one end of a long run — and compares it against the model's airflow design and any fault codes. The store's job is to hand over what was seen, not to diagnose the fan, the coil, or the refrigerant side. Staff stay on the observation side, and the technician owns the measurement and the repair.
A handoff is stronger when it carries the cabinet identity, which is why the same asset code practice used across the store's refrigerated cabinets helps here: an air curtain note tagged with the right cabinet code attaches to the right machine in a multi-run store.
Keeping this separate from water-on-the-floor checks
A weak or disturbed air curtain can end in water at the base of the case, because warm air reaching the cold front condenses and runs down. That makes the air curtain check a neighbour of the water-on-floor check, but the two are not the same record. The open chiller water on the floor guide follows the puddle — where it forms, whether it returns, what the drain and the floor conditions show — while this record follows the airflow. A store can hold both notes, and a technician reading them together gets more than either alone, but the store keeps the observations in separate entries rather than folding one into the other.
No invented airflow figures
The one thing this guide deliberately leaves out is a number. Air curtain velocity, air volume, and the energy the fans draw are model-specific values documented by the supplier, and a store record built on a remembered figure does more harm than good. When a store wants the airflow values for its exact cabinet, it asks the supplier for the model's documented figures rather than filling the log with a guess. The observation log records what was seen; the specification sheet records what the model is rated to do.
For a store choosing or reconfiguring an open chiller, the same discipline runs through selection. The multideck open chiller with top light box and the remote standard multideck open chiller each carry their own airflow and format details, and the open chiller merchandising plan guide ties the curtain back to how shelves, airflow, and aisle traffic are planned together. A cabinet set up to its merchandising plan is easier to read than one improvised on the floor.
A record that earns the service call
The air curtain check comes down to a habit: notice the signs, check the load line, note the time and conditions, and hand the technician a pattern rather than a complaint. Staff never need to measure the airflow, and they never need to guess at a figure. They need to describe what the open front is doing, and let the technician turn that description into a diagnosis.