$50 - Service Reservation
The $50 deposit reserves the repair visit and is applied toward the $298 mobilization charge.
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Residential Mini Split Repair | Greater Boston
Your mini split isn't cooling like it should. Let's find out why.
617 HVAC is a repair-first residential HVAC company based in Arlington, MA, providing mini split and ductless system repair for homeowners across 30 Greater Boston communities. We diagnose single-zone and multi-zone systems the same way, test, measure, document and put the repair price in writing before the work begins. We respond to service requests within 24 hours.

Visit & Pricing
Once the diagnosis is complete, we provide the repair price in writing before any repair work begins.
The $50 deposit reserves the repair visit and is applied toward the $298 mobilization charge.
The $298 mobilization charge covers dispatching our service team and diagnostic equipment to your home. If you approve and complete the recommended repair with 617 HVAC, the full $298 is credited toward the work.
Diagnostic time begins when your technician starts testing and measuring-not when we arrive. There is no minimum and time is billed in 15-minute increments. A 15-minute diagnosis is billed as 15 minutes.
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We inspect the equipment, test system operation and take the measurements needed to determine why your mini split is not working properly.
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We document our findings with photos, video and system readings, then walk you through the diagnosis and explain what we found in plain English.
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Once we understand the problem and the repair required, we provide the repair price in writing before the work begins.
You understand the problem, the recommended repair and the price before you decide how you want to move forward. Our technicians are paid for doing the job right - not on commission. No one in your basement earns money by finding you a bigger problem.
Why Mini Splits Fail
Mini splits are everywhere in Greater Boston now: no ductwork, no renovation, room-by-room control. The problem is that many are installed by people who aren't HVAC technicians - electricians, contractors or handymen who don't pressure-test the line set or braze connections properly. The leak develops silently, refrigerant charge drops over months and cooling capacity declines a little at a time until the system can't keep up.
Common Mini Split Failures
The most common mini split failures break into four categories. Each produces different symptoms, but the diagnostic approach is the same: read the system, test what the codes are telling us and trace the actual failure before recommending a repair.
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The most common mini split failure. We locate leaks using electronic leak detection, nitrogen pressure testing and UV dye tracing where appropriate - the same techniques HVAC service manuals specify - and repair the leak instead of topping off refrigerant on a system that will lose it again.
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Indoor and outdoor units communicate over dedicated wiring; miswired installations, wire damage and control-board faults show up as error codes we can read directly from the system.
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Blocked condensate drains, failed condensate pumps and improperly pitched drain lines are common on wall-mounted units and produce water damage complaints before they produce cooling complaints.
04
Inverter compressor issues, outdoor fan-motor failures and sensor problems typically produce specific fault codes; we read the code, verify the failure and quote the correct repair.
The symptom tells us where to start. The diagnosis tells us what to repair.
How We Actually Work
We diagnose before we recommend.
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Every modern mini split reports faults through the indoor or outdoor control board. We connect to the system and read the codes - sensor failure, communication error, pressure anomaly, compressor fault - before we open anything.
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We verify what the codes are telling us with live measurements: superheat and subcooling, refrigerant pressures, temperatures, voltages, indoor and outdoor coil conditions. On multi-zone systems, we isolate each indoor unit to identify which zone is affected.
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If refrigerant is low, we don't just add refrigerant - we find the leak. Electronic leak detectors, nitrogen pressure testing under leak-search pressure and UV dye tracing when a system is small enough to charge with dye. We document the leak location on video.
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We show you the diagnosis on video, provide the recommended repair price in writing and only start the repair after you approve it.
Complete Transparency
Photo
Photos document the condition of the equipment and the components we inspected.
Video
When a problem can be shown on video, we document it so you can see what we are seeing during the service call.
Readings
System measurements and diagnostic readings help explain how the equipment is operating and support the recommendation we make.
Every service visit becomes part of your system's documented history. You have a clearer record of what was found, what was measured and what work was completed.
Repair-First
Mini split systems are worth repairing when the failure is isolated and the rest of the system is sound. When failures repeat, refrigerant leaks recur across multiple connections or a system was so poorly installed that reconfiguration is the only fix, we say so and walk you through the replacement path.
Considering a new system or addition-room install?01
The diagnosis shows what is actually happening with the system.
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You receive a written repair option before work begins.
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Repeated failures, recurring leaks or a poorly installed system change the conversation.
Mini-split repair pricing depends on what the diagnosis finds and the work required. After diagnosis, you receive the exact repair price in writing before any repair work begins.
Adding refrigerant without finding the leak is a temporary bill, not a repair. A sealed refrigerant system doesn't consume refrigerant - if the charge is low, there's a leak and it will lose the new refrigerant on the same schedule. We locate the leak using electronic leak detection and nitrogen pressure testing, repair it, then evacuate the system and weigh in the correct charge.
We use three techniques, matched to the situation: electronic leak detection (a probe that reacts to refrigerant vapor at connections and along line sets), nitrogen pressure testing (pressurizing the system with dry nitrogen to leak-search pressure and listening or soaping joints) and UV dye tracing when a system is small enough to charge with dye and revisit. Every diagnosis is documented on video.
Yes. Whether the system has one indoor unit or eight, we diagnose the failure and isolate the affected zone. Multi-zone systems add complexity in the control communication and refrigerant distribution, which is exactly where our diagnostic process pays off.
We respond to service requests within 24 hours. During extreme weather (Boston heat waves or cold snaps), we prioritize no-cooling and no-heating calls.
Diagnostic time is billed at $198/hour with no minimum, in 15-minute increments starting when testing begins. If testing takes 15 minutes, you are billed for 15 minutes.
We diagnose installation defects the same way we diagnose failures - electronic leak detection, control-board reads and airflow checks reveal most installation problems within an hour. If reconfiguration is the right fix, we can do it or coordinate with our installation team; if a full reinstall makes more sense, we'll say so.
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617 HVAC provides residential mini split and ductless system repair for homeowners across Greater Boston. Based in Arlington, our repair-first approach starts with understanding the system before recommending the next step.