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Job card: steakhouse walk-in with wandering temperatures, caused by a corroded wall-mounted thermostat with its bulb tacked to the panel; replaced with a Johnson Controls A19ABC-24C in a proper enclosure with the bulb in the return air

Steakhouse walk-in cooler holding erratic temperatures. Fine one day, warm the next, no pattern.

Walk-in wall panel with a rust stain where the old thermostat was mounted and the capillary bulb wire tacked along the wall

The old thermostat had been mounted straight onto the wall panel, where condensation had rusted through the back of it. The capillary bulb was tacked along the wall on a bit of wire, so it was reading the panel more than the air. The rust stain is where it used to live.

Box of a Johnson Controls Penn A19ABC-24C temperature control showing its range and capillary specification

We replaced it with a Johnson Controls / Penn A19ABC-24C, the standard mechanical cold-room control: -30 to 100°F range, adjustable differential, 8-foot capillary.

New Penn temperature control mounted beside an Intermatic defrost timer box inside a walk-in, connected with conduit

The new one got a proper enclosure, conduit into the defrost timer box next to it, and the bulb positioned in the return air path where it senses what the product is actually sitting in. Placement matters more than the control. A perfect thermostat reading the wrong spot gives you a perfect wrong number.

Two-fan evaporator mounted at the ceiling of a walk-in cooler above wire shelving

Evaporator checked while we were there: both fans running, coil clean, defrost verified on the timer.

If your walk-in’s temperature wanders, the thermostat and where its bulb sits is the first place to look. It’s the cheapest part in the box, and it makes all the decisions.

If it heats or cools, we handle it. 📞 718-802-1700

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