Equipment
Commercial air conditioning repair
Most commercial AC failures we attend are not failures of the equipment. They are consequences of deferred maintenance, a clogged filter freezing an evaporator, or a furred condenser tripping a high-pressure lockout on the first hot day.
Answered live, 24/7 (617) 938-5404What actually goes wrong, in order
| Fault | Symptom | The check |
|---|---|---|
| Clogged filters | Weak airflow, then a frozen evaporator coil | Look at the filter first, every time. It is free and it is often the answer |
| Dirty condenser coil | Runs constantly, high head pressure, trips on high-pressure lockout | Head pressure and amp draw against nameplate |
| Failed run capacitor | Motor hums, struggles to start, trips the overload | Replace below 10% under rated microfarads, do not wait for total failure |
| Contactor failure | Nothing happens on a call for cooling | 24V control signal present at the coil, no line voltage at the load side. Check for pitted or welded contacts |
| Blower motor or belt | Air handler silent or weak, no air at the registers | Zero amps during an active call means a failed motor or winding |
Normal superheat at the evaporator outlet on a correctly charged system is 8 to 15°F. Outside that range with the charge confirmed correct points at the metering device, not the refrigerant.
A note on what we take on
We service commercial air conditioning as part of keeping a commercial kitchen or retail space running, the equipment sitting alongside the refrigeration we are already there for. Larger rooftop plant is a different trade with different licensing in Massachusetts, and where a job falls outside what we should be doing, we will tell you that plainly rather than take it on and work it out later.
If you are not sure which side of that line your unit sits on, the tonnage is on the data plate. Tell us when you call and we will give you a straight answer before anyone is dispatched.
Winter, and why it breaks things here
New England does something to outdoor equipment that warm-climate service literature never addresses. Below about 70°F ambient, head pressure on a refrigeration circuit falls far enough to starve the metering device; combine that with wind on an exposed rooftop and simple fan cycling stops being enough. If your equipment misbehaves only in the coldest weeks, that is a head pressure control problem and it will recur every winter until it is corrected.
Common questions
My AC is blowing warm air. What is the most likely cause?
There is ice on my AC lines in summer. Is that normal?
Do you handle large rooftop units?
Related
Cooling down in a working kitchen?
Have the tonnage from the data plate ready and we will tell you straight away whether it is a job for us.
Get in touch
Request service or a quote
If something is down right now, call. The phone is the fast path, day or night. For quotes, maintenance plans and installs, send the form.