Holding equipment does the quietest job in the kitchen: no searing, no boiling — cooked food kept hot, safe and presentable for hours, in bain-maries, holding cabinets, proving cabinets and heated displays. The thermostat duty looks easy and is constantly underestimated. The temperatures are low, the hours are endless, and food quality punishes every overshoot the control allows.
The holding duty: gentle, continuous, unforgiving
A holding control spends its life switching gently around a narrow, low band — which means the specification that matters is not headline range but behaviour at the working point: resolution on the dial where the chef actually works, and contact endurance across years of continuous service. Our control family is tested to 100,000 cycles, and setpoint ranges are configured to order, so the adjustable band can be centred on your holding temperatures instead of spread across temperatures the equipment will never see.
Wet wells and dry wells
A wet bain-marie well is forgiving: the bulb sits in the water jacket, the water buffers every swing, and the food sees a steady temperature. A dry well is a different control problem — the element heats the well metal directly, response is fast, and a bulb that reads air instead of metal will overshoot and hunt. Seat the bulb firmly against the well wall or in its well, in metal-to-metal contact. Heated display decks and shelves are dry duty of the same kind: what the bulb touches decides what the food gets.
Control selection, well by well
The AG16-K (16A / 20A · 110V / 250V, 50–400°C platform, ranges configured to order) is the standard holding control; the compact AGO series fits countertop warmers where panel space is tight; SPDT contacts add a pilot light showing the well is at temperature. One rule is worth its own paragraph: one control per well. Wells are loaded differently — one full, one nearly empty, one refilled with cold product — and a single bulb can only tell the truth about the well it sits in. Sharing one control across wells guarantees that some of them are held wrong. For large warming and proving cabinets on three-phase supplies, the three-pole AG32-3K switches all phases together at up to 50A.
Boil-dry and dry-fire: the limiter still applies
Low working temperatures do not mean low fault temperatures. A wet well that boils dry, or any well whose control contact welds, keeps heating — and holding equipment often runs unattended, including overnight. Fit an independent manual-reset limiter (AG16-S, fixed trip points factory-set to your specification) in series with the control. If it ever trips, the equipment stays off until someone finds out why: that is the correct behaviour for a fault in an empty kitchen.
Certifications
Our thermostats are produced under a TÜV-certified quality system — certificate R50309054 (EN 60730-1 / EN IEC 60730-2-9), verifiable on Certipedia. Confirm the approvals carried by the specific models you select for the markets you sell into.
FAQ
Can one thermostat run a four-well bain-marie?
It can switch the elements, but it can only sense one well. Wells loaded differently drift differently, so three of the four would be held at whatever temperature the sensed well dictates. One control per well is the honest design, and it is how the equipment holds temperature across a service.
Why does food dry out at the edges even at the right setpoint?
Usually overshoot, and usually the bulb: seated against air instead of the well metal or water jacket, it reads late, the element overruns, and the food pays for the swing. Firm bulb contact and a setpoint band configured around the holding temperature narrow the swing considerably.
Is a safety limiter really necessary on low-temperature equipment?
Yes. The limiter is not there for the working temperature; it is there for the fault — a welded contact or a boiled-dry well takes temperatures far beyond the holding band, often with nobody watching. A manual-reset limiter is cheap insurance that stays off until checked.
Capillary Control Thermostats · Manual Reset Safety Limit Thermostats · How to Choose a Capillary Thermostat