A commercial dishwasher is two heated water circuits in one cabinet. The wash tank is held hot through the whole service; the booster heater takes the final rinse water up to sanitising temperature in seconds, at the highest power density in the machine. Both circuits are thermostat jobs — and the booster adds a third: protection against firing dry. This guide works through all three.
Wash tank control: the steady job
The tank element cycles all day, every day. The temperature band is modest, so what decides the control’s life is endurance, not range: our control family is tested to a mechanical life of 100,000 cycles under load. The AG16-K (16A / 20A · 110V / 250V, 50–400°C) is the standard fit; choose SPDT contacts when the same control should also drive an “at temperature” pilot light, so operators can see at a glance that the wash water is ready.
Booster heater control: the hard job
The booster is a small vessel with a big element, and it is switched hard and often. Start with current: size the control against the element’s actual draw with margin for continuous duty, never at 100% of rating. The control models we fit to dishwasher heating:
| Model | Rating | Range | Reset |
|---|---|---|---|
| AG16-K | 16A / 20A · 110V / 250V | 50–400°C | Automatic |
| AGO SERIES | 16A / 20A · 110V / 250V | 50–400°C | Automatic |
| TY316 | 16A · 110V / 250V | 50–380°C | Automatic |
Technical data is a catalogue reference. Confirm final ratings, dimensions and approvals for the selected model before ordering.
Dishwasher water temperatures sit at the low end of these ranges, which is why setpoint ranges are configured to order: tell us the wash and rinse temperatures and we set the adjustable band around them, instead of leaving your working point in the bottom sliver of a wide scale where dial resolution is coarsest. For the heaviest single-phase booster loads, the AG32 family takes over — the AG32-1K up to 32A, and a 20A / 250V AG32-2S variant built specifically for water-heater duty.
Dry-fire protection: the limiter that earns its place
A booster’s worst minute is a low-water one: the element finds itself in air instead of water, and its temperature runs away while the control — sensing water temperature, or what is left of it — may see nothing wrong. The defence is an independent manual-reset limiter with its own bulb on the booster vessel: AG16-S, with standard fixed trip points at 380 / 400 / 430°C or a trip point factory-calibrated to your specification, set above the highest legitimate vessel temperature and below the temperature that damages the element and seals. Manual reset matters here more than anywhere: a dry-fire event means a fault — level control, fill valve, scale — and the machine should not quietly re-arm before someone looks.
Steam, scale and wet panels
Everything inside a dishwasher is wet, steamed or scaled. Keep the switch body out of the splash zone and let the capillary reach the tank; where the control must live in the wet zone, the TY316 is available in a waterproof version. Seat bulbs in their thermowells with firm contact, and design for descaling access: a bulb insulated by scale reads late, the water overshoots, and the first symptom looks like a thermostat fault — our troubleshooting guide covers the pattern.
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
Why does the booster heater need a separate limiter if it already has a control thermostat?
Because the dangerous event — firing with low water — is precisely the one the control may not see: it senses water, and there is too little water to sense. An independent limiter with its own bulb on the vessel is the backstop, and manual reset forces a service check before the machine runs again.
Our wash and rinse temperatures are under 100°C — isn’t a 50–400°C range the wrong part?
The headline range is the platform, not the part you receive: setpoint ranges are configured to order, so the adjustable band is set around your wash and rinse temperatures with usable dial resolution. Ratings, contacts and capillary are configured the same way.
Which control suits the wettest part of the machine?
The TY316 is available in a waterproof version for controls that must sit in a damp or splash zone. More often the better design is to mount the standard control in a dry area and let the capillary and bulb reach into the wet zone.
Capillary Control Thermostats · Manual Reset Safety Limit Thermostats · Capillary Thermostat Troubleshooting