Rooftop Unit Service in Hermann, MO

Signs a rooftop unit needs attention

Nobody sees an RTU fail. You see it in the rooms below, so start with the symptom and work up.

What wears out RTUs around Hermann

Three local conditions shorten the life of a unit here. Heat comes first: BestPlaces counts about 27.6 days above 90°F each year here, which means long run times on a black or tar roof, where the air around the coil is hotter than the street.

• Cottonwood and river debris. Fluff from the river bottoms mats on condenser coils in late spring, and the compressor runs hot behind it.
• Humidity. Valley humidity keeps the evaporator wet and the drain busy. An algae plug in a trap can send water across the roof or through the ceiling.
• Old brick buildings. Hermann's downtown storefronts were built long before rooftop equipment. Many units sit on later curbs, behind parapets, with awkward access and ductwork threaded through upper floors.

How do we inspect a rooftop unit?

We read the whole unit, because a package unit puts every system in one box. Refrigeration, airflow, gas heat, controls and outside air all share the same cabinet, and one can hide another.

A full inspection covers filters and belts, blower amperage, both coils, condensate drain and trap, contactors and capacitors, the refrigerant circuit, burners and the heat exchanger on gas units, the curb seal, and the economizer.

The economizer gets its own check because it is so often broken. A UC Davis paper presented at the 2014 ACEEE Summer Study compiled field studies showing failure rates from 43% to 100%, and one field study found problems on 64% of 124 units of 10 tons or less. Its faults were sensor or control failures (46%), stuck dampers (38%) and poor operation (16%). Those are California studies, not Hermann numbers, but the parts are the same. A closed damper means the building may be taking in no outside air at all.

RTU repair, tune-up or rooftop HVAC replacement?

Most decisions come down to four options, and each has a cost beyond the invoice.

For a compressor or heat exchanger on an aging unit, have a new-unit price in hand before you approve the repair. On a building where the roof will not take a new unit, a split system or ductless zones may be the better move. Our rooftop unit replacement guide walks through the planning.

The visit, step by step

Here is what is included when we come out, and the order we work in.

1. We confirm access: hatch or ladder point, keys, and any tenant who needs notice.
2. We record the data plate: model, serial, tonnage, refrigerant and heat type.
3. We kill power at the disconnect and open the panels.
4. We inspect the unit from filter to flue and test under load.
5. We photograph what we found, then explain the fault and your options.
6. We quote the work before we start.
7. We finish the repair, run the unit through a full cycle and check supply air at the space below.
8. We close the panels, confirm the disconnect and leave you a record of the work.

Have you lost cooling on a day you cannot close? Tell us when you call, so we can talk through what is realistic. Office hours run Monday to Friday, 8 to 4, and we do not promise a time until we know the job.

Timeline, aftermath and prevention

A repair ends when the part is in and the unit has run a full cycle. A replacement runs on a longer clock: measure, order, permit, crane date, roof set, start-up. Plan the crane for your slowest morning, and do not book it for a festival weekend in Hermann.

Ask about the permit early. As of late 2026 Missouri issues no statewide HVAC contractor license, so local offices set the rules, and the Missouri HVAC Authority reports that a straight swap usually still needs a mechanical permit. We cannot confirm whether rooftop equipment visible in the Hermann Historic District gets reviewed, so check with the city. Whoever you hire, EPA Section 608 reserves refrigerant handling for certified technicians.

After that, put filters, coils and the economizer on a calendar, because nobody walks past a rooftop unit. Our commercial maintenance page lays out what a seasonal visit covers. If a unit has already quit, start with commercial repair.

What changes the price of rooftop work?

Tonnage, crane, curb, heat type and access drive the bill. These national 2026 figures from PICKHVAC help you budget, and they are not our prices.

The same source lists curb replacement at $800 to $6,000 as a separate add-on. Repair costs depend on the part and on how long it takes to reach. Ask for a clear, upfront quote once we have seen the unit.

Why Brian Grannemann Services for rooftop unit service

• Our Hermann office has been open since 1998, and you can walk in at 124 E 10th St with a question.
• Heating and cooling share a cabinet on these units, and we work on both, so one company can answer for the whole box.
• Electrical is on our trade list too, which matters at the disconnect and the control wiring.
• Weber S. counts roughly six jobs with us, and his review uses the word fair.

We serve commercial buildings from Hermann out to New Haven, Owensville, Union and Washington. Call (209) 563-1270 with the tonnage if you know it.