A walk-in cooler or freezer installation scope should cover the insulated panel box and floor, the door and hardware, the evaporator and condensing unit, defrost method, refrigerant line sets, drains, the electrical boundary, startup, a documented temperature pulldown and food safety requirements. Freezers add heater requirements and floor details that coolers do not need.
- Decide cooler or freezer first. Freezers need heated door frames, a floor strategy and a defrost approach that coolers can skip.
- The box and the refrigeration system are separate packages. Scope who assembles panels, who sets the equipment and who connects them.
- Line sets and drains are where most installation surprises show up, particularly when the condensing unit is on a roof.
- Electrical stops at a named disconnect. Power, lighting circuits and door heater circuits need a licensed electrical party.
- A documented pulldown with recorded temperatures proves the box works before food goes in.
Start with the box, not the compressor
A walk-in has two halves. The enclosure is a prefabricated insulated box made of foamed panels. The refrigeration system is an evaporator inside and a condensing unit outside. Operators tend to buy them as a package, but the scope should still split them, because different people handle each half and different things go wrong.
For background on how walk-ins work and fail, the walk-in cooler and freezer guide is the companion read. This page is only about writing the installation scope.
Panels, floor and door
- Dimensions and location: Interior size, ceiling height, clearances to walls, sprinklers and lights, and the path the panels take through the building.
- Panel assembly: Cam-lock or equivalent joining, sealed seams, and trim at the ceiling and wall transitions. Say who levels the slab.
- Floor: An insulated floor panel, or a flush floor on a slab prepared with insulation. Freezers on grade need a way to prevent frost heave, such as a heated sub-floor or a raised, ventilated floor system.
- Door: Swing direction, hinge and closer type, strip curtains or a gasket package, a view window, and a heated frame on freezers.
- Interior finish: Shelving, kick plates, and floor surface rated for traffic and washdown.
A walk-in assembled in an existing kitchen often has to fit around hoods, drains and ceiling structure. Photograph the install location, list the obstructions and let the scope say who relocates a conflicting sprinkler head or light fixture. Those belong to other trades.
Evaporator, condensing unit and defrost
| Item | Cooler | Freezer |
|---|---|---|
| Evaporator defrost | Often off-cycle or electric | Electric or hot gas, on a timed schedule |
| Door frame heater | Not usually needed | Required to prevent ice at the frame |
| Floor | Insulated panel or flush floor | Insulated floor with a frost heave strategy |
| Drain heat | Rarely needed | Heated drain line or trace heat |
| Controls | Thermostat or controller with a defrost timer | Controller with defrost termination and alarm |
State where the condensing unit goes: outdoor on a pad, on a wall rack, on a roof, or inside as a self-contained system. Outdoor and roof units face Southern California heat and, near the coast, salt air. Ask for coastal protection where it applies. The refrigeration and coolers service page explains how Davinci approaches ongoing service for these systems.
Defrost choice affects energy use, product temperature swings and drain design. The scope should name the defrost method and the controls that terminate it.
Line sets, drains and penetrations
- Define the line set route, from the evaporator through the box wall to the condensing unit, including length, rise and any roof penetration.
- Specify pipe sizing based on the manufacturer's data and the actual route, with insulation on the suction line.
- Require brazing with a nitrogen purge, a pressure test and an evacuation before charging, with results recorded.
- Route the evaporator condensate drain to an approved connection with a trap, and heat it on freezers.
- Seal every penetration through the box and the building envelope so the wall insulation and vapor barrier are not defeated.
Kitchens rarely have a convenient floor drain near the right wall. Add the drain to the scope as a visible item and name the plumber if one is needed. A drain issue discovered after panels are up often costs more than the refrigeration itself.
The electrical boundary
Walk-ins need power for the condensing unit, the evaporator fan and defrost heaters, interior lighting, and, for freezers, door and drain heaters. Each is a separate circuit or a separate branch off a panel. Davinci's own crew performs the refrigeration and controls work, and does not perform primary electrical service, panel or feeder work, so the scope must name the electrical party and identify the disconnect where mechanical work begins.
- Disconnect at the condensing unit, within sight, with the circuit sized by the manufacturer's data.
- Evaporator power and defrost circuit from the panel to the evaporator.
- Lighting and door heater circuits, if separately fed.
- Alarm or monitoring connections, and the network or phone line for remote alerts.
Startup, pulldown and health code
Startup is complete when the box has pulled down from ambient to its setpoint and held it. The scope should require recorded temperatures at intervals during pulldown, final superheat and subcooling readings, confirmation that defrost runs and terminates, and a test of any high-temperature alarm. Product should not be loaded until the box holds its setpoint.
Food service operators answer to the California Retail Food Code, which requires cold holding at 41 F or below. Inspectors and plan checkers may ask for a thermometer, a clean washable interior and a drain arrangement that meets code. Confirm current requirements with the local environmental health department, and review the restaurant temperature logs and health inspections page for the documentation side. The industries pages for restaurants and grocery and retail describe the sites where these boxes usually land.
Contractor shall furnish and install the walk-in enclosure, door and floor as scheduled, together with the evaporator, condensing unit, refrigerant line sets and condensate drain. Piping shall be pressure tested and evacuated with recorded results. Owner shall provide power to the disconnect locations identified by a licensed electrical contractor. Contractor shall complete startup and record a temperature pulldown before product is loaded.