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Troubleshooting

True Prep Table Temperature Problems: Common Faults and What They Cost to Fix

If your True prep table is running warm, it's usually dirty condenser coils, a worn gasket, or a refrigerant issue. Here's how to read the symptoms and when to call a tech.

By June 12, 2026 5 min read

If your True prep table is running warm, the most likely culprits are dirty condenser coils, a failing door gasket, or a refrigerant issue. Most of these are fixable without replacing the unit. Here’s how to read what’s going on.

Why True Prep Tables Run Warm

True makes solid equipment, but every prep table eventually runs into the same cluster of problems.

Dirty condenser coils are the number one cause. On the TSSU sandwich/salad line, the condensing unit sits at the rear of the cabinet. In a kitchen running 10-14 hours a day, coils can get fully choked with grease and dust in a few months. When airflow is blocked, the refrigerant can’t shed heat and the cabinet temperature climbs. You’ll often notice the compressor running constantly before the temperature actually drifts.

Worn door gaskets are a close second. The magnetic gaskets on True prep table lids and doors compress over time. Run a dollar bill along the gasket seal: if it slides out without resistance, cold air is leaking. A failing top gasket on a sandwich unit is easy to miss because the lid looks fine from a distance.

Refrigerant leak is less common but worth knowing about. If the unit cools fine in the morning and gradually loses hold through a busy lunch service, a slow leak is a real possibility. You’ll typically see frost patterns that look wrong, maybe heavy frost on just one section of the evaporator, or none at all.

Evaporator fan motor failure is another one. The fans circulate cold air through the cabinet. If one stops, you’ll get uneven temperatures, one rail staying cold while another warms. A failed motor is sometimes confused for a refrigerant problem because the symptoms overlap.

Thermostat or temperature controller issues come up too, more so on older analog units than on the current digital controllers. If the unit overcools in the morning and underperforms in the afternoon, the controller is worth checking.

How a Tech Actually Diagnoses This

A good refrigeration tech won’t just pull out the gauges and start checking refrigerant. The first pass is visual: coil condition, fan operation, gasket seals, physical signs of frost or oil streaks (which can point to a leak). Then temperature probes map the actual cabinet readings against what the controller is calling for.

If the coils are dirty, that gets addressed first, because it changes everything downstream. A unit with blocked coils will show artificially high head pressure, which can look like a refrigerant overcharge if you’re not paying attention.

Refrigerant diagnosis requires manifold gauges and a leak detector. On True equipment, the refrigerant type varies by model year. Units built before around 2015-2017 typically used R404A; newer models use R290 (propane-based). The tech needs to confirm what’s in the system before touching anything.

What You Can Check

The dollar-bill test on your door and lid gaskets is a quick field check any operator can run. Slide a bill around the seal: if it pulls out without resistance anywhere, cold air is leaking. Note where and let your tech know.

Condenser coil condition is worth eyeballing too. If you can see visible buildup on the fins, flag it. Most operators schedule coil cleaning as part of a PM visit every 90 days, more often in a high-grease environment. It’s the single most effective thing you can do to keep the unit running reliably, and it’s worth having on a maintenance contract so it doesn’t slip.

Everything else (refrigerant, electrical controls, evaporator work) is a pro job. Refrigerant work requires EPA Section 608 certification under federal law. Getting it wrong can damage the compressor and turn a modest repair into a major one.

What Repairs Actually Cost

Ranges here are rough. Parts availability, refrigerant type, and labor time all affect the final number. Get a quote before authorizing anything.

Condenser coil cleaning as a standalone service is typically modest, often bundled into a PM visit. Gasket replacement is usually straightforward parts-and-labor. Evaporator fan motors vary depending on whether you’re using OEM or aftermarket parts. Refrigerant work varies most: the labor to find and fix the leak is separate from the refrigerant cost itself. A minor access valve leak is one thing; a cracked evaporator coil is another. Controller or thermostat replacement is generally available through authorized True suppliers.

None of these repairs are reasons to replace a prep table that’s otherwise in good shape. True backs their equipment with an industry-leading warranty, and well-maintained units can last well beyond the typical commercial refrigerator lifespan.

Call Us

Call when the condenser is clean and the gaskets pass the dollar-bill test but the cabinet still won’t hold temp. Call when you see frost in unusual patterns. Call when the compressor is running nonstop or short-cycling. Those symptoms mean something in the refrigeration circuit needs gauges and expertise to sort out safely.

Don’t wait until product is at risk. A warm prep table is a food safety issue, not just an equipment problem.

Bay Area Refrigeration Service handles True equipment and most other commercial refrigeration brands across the Bay Area. We’ll get you on the schedule fast, often same or next day when we can. Reach us at bayarearefrigerationservice.com.

FAQ

Common questions.

Why is my True prep table not holding temperature during a busy service?
The most common reasons are blocked condenser coils, a failing door or lid gasket, or a slow refrigerant leak. Coils choke up fast in a working kitchen, and a gasket that looks fine from a distance can still be leaking. If you're not sure which it is, that's exactly what a diagnostic call is for.
Can I recharge the refrigerant in my True prep table myself?
No. Refrigerant work requires EPA Section 608 certification under federal law. An improper charge can damage the compressor or mask an underlying leak, turning a modest repair into a major one.
How often should I clean the condenser coils on a True prep table?
Every 90 days in a typical commercial kitchen, more often in a high-grease environment like a burger or pizza operation. Most operators build this into a PM contract so it doesn't get skipped. If yours haven't been serviced in a while, that's a good first call to make.
Is it worth repairing a True prep table that's 10 years old?
Usually yes. True equipment is well-built and they back it with an industry-leading warranty. Unless the compressor has failed on a very old unit, most temperature problems are caused by components that are cost-effective to replace. Get a diagnosis before writing off the unit.

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