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Job card: follow-up on a thawed rooftop unit, supply air measured at 55 degrees and the dining room holding 70; the unit is a 2002 Rheem RKKB-A120CL22E on R-22, so a planned replacement is advised

A few days after we thawed this rooftop unit out and gave it new filters, we went back with a thermometer. Fixing a frozen coil is one thing. Proving the unit is actually doing its job is another.

Two pocket thermometers clipped to the rooftop unit panels reading 55.0 and 58 degrees Fahrenheit

Supply air at the unit: 55°F out of the evaporator section, 58 at the filter access. Inside, the thermostat holding the dining room at 70 against a 72 setpoint on a warm afternoon. That’s a unit doing what it’s supposed to.

Honeywell thermostat display reading inside 70 degrees with a cool setting of 72

The unit itself is worth a look. A Rheem RKKB-A120CL22E, ten tons nominal, two compressors, built in October 2002. Refrigerant: R-22.

Data plate of a Rheem RKKB-A120CL22E rooftop unit listing R-22 refrigerant and a fabrication date of October 2002, with the serial number redacted

That last line is the one that matters for the owner. R-22 hasn’t been produced or imported in the US since 2020. Reclaimed gas still exists, but it’s expensive and getting more so. On a 23-year-old unit, any repair that opens the system now comes with a refrigerant bill that used to be an afterthought.

Compressor compartment of a rooftop unit showing two compressors with copper suction and discharge lines

Both compressors are fine today. The honest advice is to budget for a replacement on your own schedule, in the off season, rather than in August when it fails and every contractor in the city is booked.

We’ll keep this one running as long as it makes sense. We’ll also tell you when it stops making sense.

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

Service: Commercial HVAC service.

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