If your True refrigerator stopped cooling overnight, the most common culprits are a dirty condenser, a failed evaporator fan motor, or a refrigerant leak. The fix depends on which unit you’re running and how far along the problem is.
T-Series vs. GDM: Different Units, Different Access Points
True T-series reach-ins (the two- and three-door stainless boxes in most restaurant lines) and GDM glass-door merchandisers share the True name but have different access points, airflow paths, and control layouts. A GDM-23 in a convenience store fails in ways a T-49 reach-in usually won’t, so knowing which unit you have matters before you start chasing symptoms.
Both the T-series and GDM lines use a bottom-mounted condensing unit, accessible from the front grille at the base of the cabinet. Good clearance around the unit matters for heat rejection. Both are well-built, but both punish deferred maintenance.
Most Likely Causes, in Order
Dirty condenser coils. This is the first thing I check on any True unit that’s running warm. The condenser coil sits behind the front grille at the bottom of the cabinet on both T-series and GDM models. Thick dust buildup forces the compressor to work harder, and eventually it can’t keep up. A good coil cleaning takes maybe 20 minutes and fixes a surprising number of “not cooling” calls.
Evaporator fan motor failure. True uses multi-speed fan motors in GDM models. When a fan motor fails, cold air pools near the evaporator instead of circulating across all shelves. You’ll notice uneven cooling, warm spots on certain shelves. On T-series reach-ins, a failed evap fan usually means the whole box starts climbing.
Door gaskets and door alignment. Walk-in customers almost never cause this one, but bar owners with GDMs absolutely do. A torn gasket or a door that got bumped out of square lets warm air infiltrate all night. Run your hand around the door perimeter when the unit is running. If you feel cold air escaping, you’ve found part of your problem.
Refrigerant leak. True units don’t just lose refrigerant on their own. When you find low refrigerant, there’s a leak somewhere, either at a fitting, at the evaporator coil, or occasionally at the condenser. Topping off without finding the source is a short-term fix that will leave you back in the same spot in a few months. California has specific regulations around refrigerant handling, so this one requires a licensed tech regardless.
Control board or thermostat issues. True’s electronic controller boards (present on most GDMs made in the last 10-15 years) can develop issues, especially in high-humidity environments. A board fault might show as the unit not calling for cooling even when the box is warm, or as erratic temperature swings. Depending on the model and controller generation, the display may show a fault code. This is less common than the mechanical causes above, but it’s worth knowing the board is a real failure point on True GDMs. If the unit powers on and the display shows normal but the compressor never kicks on, the board or thermostat is high on the suspect list.
Compressor failure. The compressor is usually the last component to fail, not the first. True uses commercial-grade compressors (Embraco among others), and they tend to give warning signs before dying outright: hard starting, clicking on and off, running hotter than normal. A compressor that’s genuinely failed means a bigger repair conversation.
What a Tech Actually Does On-Site
When I send a tech to a True unit that’s not cooling, the diagnostic goes roughly like this:
Check the condenser and evaporator for airflow blockages first. Pull the front grille, look at the coils, check that all fans are spinning. This takes five minutes and rules out the most common causes.
Measure supply air temperature and return air temperature at the evaporator. A unit with a refrigerant problem will show a smaller-than-normal temperature split. One with an airflow problem will show the opposite, the evaporator is freezing up and the supply air is restricted.
Check the evaporator coil for ice buildup. If the defrost cycle has been failing, you may find the coil fully iced over. A defrost heater that’s stopped working will let frost accumulate until airflow is almost completely blocked. A frozen evap coil can mimic a refrigerant problem completely until you defrost it and run the unit again.
If the refrigerant side is suspect, check suction and discharge pressures with gauges. This tells you whether the system is undercharged, whether the compressor is pumping, and whether the metering device is functioning.
For GDMs specifically, check the controller board for fault indicators. True’s electronic controllers may display a fault code or show an abnormal display pattern depending on the model. Always worth cycling power once to rule out a transient fault before assuming the board is bad.
What’s Safe to Do Yourself
Cleaning the condenser coils is something any operator can do safely. Power the unit down, pull the front grille, and use a coil brush or compressed air. Do it at least every three months in a busy kitchen. This single habit prevents a large percentage of service calls.
Door gasket checking is also worth doing yourself. Run your hand around the door perimeter when the unit is running and feel for cold air escaping, or close the door on a dollar bill and see if it drags. If the gasket is torn or compressed flat, note the model number and call us for a replacement. It’s a quick fix.
Everything beyond that, refrigerant, the compressor, the control board, internal wiring, is licensed-tech territory. Refrigerant work requires EPA Section 608 certification and California has additional state-level requirements on top of that. More practically, doing it wrong on a reach-in or merchandiser means spoiled product on top of whatever the repair costs.
Call Us
If condenser cleaning and a door gasket check don’t bring temps back down, something else is wrong. At that point you’re into refrigerant, electrical, or compressor territory, and the diagnostic requires gauges and hands-on access a tech needs to do right.
Bay Area Refrigeration Service handles True T-series and GDM units regularly. We carry common components (fan motors, defrost heaters, controller boards) and will get you on the schedule fast, often same or next day when we can. Call us before the product loss turns into a bigger problem.