Most often a refrigerant loss, an iced evaporator, a failed defrost, or a door seal letting warm air in all day. All four are usually repairable.
A straightforward room is typically two to three days on site once panels arrive. We will give you a realistic date, and work around trading hours where we can.
Yes. Doors, seals, heaters and individual panels can all be replaced without rebuilding the room.
Usually yes. Modern insulation and controls, correctly sized, use noticeably less than a twenty year old room with tired seals.
Yes, and we plan around service times. Most kitchens cannot lose their cold storage for a day, so we sequence the work accordingly.

