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Commercial · Commercial Split SystemsCommercial Split System Installation & Repair
Commercial split system installation and repair covers 5 to 20 ton systems with the two halves in different places: an air handler or a furnace and coil indoors, and a condensing unit on the ground or the roof, joined by refrigerant piping. A split is the right choice when a rooftop unit cannot be used, because the roof has no capacity or access, the landlord will not allow new penetrations, or the space is on an upper or interior floor. The limit to check first is the piping: every model has a maximum line length and vertical lift, and a layout beyond them needs different equipment.
A commercial split is the same idea as a house air conditioner at several times the size. Indoors there is an air handler with a blower and a cooling coil, hung in a ceiling space or standing in a mechanical room, or a furnace with a coil on top where gas heat is wanted. Outdoors there is a condensing unit on a pad at grade, on a wall bracket or on a roof curb or sleepers, often with two compressors so it can run at part load. Interior zones with no room for duct mains can use ducted ceiling cassettes or concealed units fed from the same kind of outdoor equipment.
A packaged rooftop unit is simpler and usually cheaper to install, so a split has to earn its place. It does when the roof structure cannot take the weight without reinforcing, when there is no practical way to get a unit and a technician onto the roof, when the lease forbids new roof openings, or when the space is a second-floor or interior unit with other tenants between it and the roof. Only two refrigerant pipes, a drain and control wiring link the halves, and they can pass through a wall or a shaft where a duct never would. The trade-off is laid out in RTU versus split system.
Line length and lift are the engineering limits. The installation manual for each condensing unit states a maximum equivalent piping length and a maximum height difference between the two halves, with pipe sizes that change as the run grows, and capacity falls as the line gets longer. Long or tall runs may call for a larger suction line, added refrigerant and accessories such as a liquid-line solenoid or a crankcase heater. We measure the route before quoting equipment, because a condensing unit picked from a catalogue and then set far beyond its rated distance from the coil is a compressor failure waiting for a hot week.
Voltage is the Ontario detail that catches equipment orders. Plazas and smaller buildings are commonly supplied at 120/208 V three-phase, while many industrial and larger commercial buildings have 347/600 V service, for which equipment is ordered as 575 V. The condensing unit and the air handler have to match what the panel provides, and a 208 V unit cannot be connected to a 600 V supply without a transformer, so we read the panel and the existing nameplates before anything is ordered. Power wiring and disconnects are installed by a licensed electrical contractor, who files the notification with the ESA.
Refrigerant is the other. New split equipment has moved from R-410A to R-454B, a mildly flammable A2L refrigerant, and the two are not interchangeable: an R-454B condensing unit cannot be paired with an older R-410A coil or air handler unless the manufacturer lists that exact match, and generally it does not. When one half of an R-410A system fails, the choices are to repair it with R-410A parts while they remain available, or to replace both halves together. A2L air handlers also commonly carry a refrigerant sensor and a control that runs the blower if a leak is detected, one more reason the halves must be a listed pair; the background is in our A2L refrigerant guide.
Installed price depends on tonnage, line length and route, crane or lift needs, electrical work and ductwork changes, and repairs depend on the refrigerant, the part and the access, so both are quoted in writing and no flat commercial figure is published. Opening the refrigerant circuit takes a 313A refrigeration and air conditioning systems mechanic with an ODP card, and a gas-fired furnace section takes a TSSA-licensed gas technician. Splits specified during a renovation are part of tenant fit-out HVAC, and breakdowns in the cooling season are handled under commercial air conditioning repair. Start at commercial HVAC for the overview, or ask the shop for a site visit.
Equipment we install and service
The indoor half: a blower, filter rack and cooling coil in one cabinet, or a gas furnace with a cased coil. Belt-drive blowers need belts and bearings checked, and the drain pan and trap need cleaning, since an indoor unit above a ceiling floods the space below when the drain plugs.
The outdoor half, with one or two compressors, a condenser coil and fans. Ground-mounted units need clearance for airflow and protection from snow, vehicles and vandalism; roof-mounted units need a curb or sleepers the landlord has approved.
Copper suction and liquid lines, insulated, supported and sized to the manual for the length of the run. Joints are brazed with nitrogen flowing through the pipe to keep scale out, then the system is pressure-tested, evacuated and charged by weight with the allowance for line length.
Low-profile indoor units for interior rooms and corridors with shallow ceiling space. Each has its own filter and a condensate drain or pump, which makes access panels in the finished ceiling part of the installation, not an afterthought.
What goes wrong in these buildings
- The landlord will not let us put anything new on the roof and we still have to cool the second floor.
- The outdoor unit died and the supplier says the new one will not work with our old air handler.
- The equipment showed up at 208 volts and the building is 600.
- Water came through the ceiling under the air handler in the first hot week of summer.
- The condensing unit sits at the far end of the building from the coil and trips on every hot afternoon.
- Nobody will give me a price without seeing where the pipes would run.
How it works
We measure the piping route and height difference, confirm the supply voltage and available breaker space, check the roof or pad location against the landlord's rules, and calculate the load. The quote names matched indoor and outdoor model numbers, the refrigerant and the line sizes.
The indoor and outdoor units are set, the piping is brazed, pressure-tested with nitrogen and evacuated, and the electrical contractor connects power. Ductwork is connected or adapted, the drain is trapped and tested with water, and the thermostat is configured for the stages the equipment has.
The system is charged by weight, then run while we record pressures, superheat and subcooling, supply and return temperatures and motor currents against the manufacturer's data. You get that start-up sheet with the model and serial numbers, the refrigerant type and charge, and the warranty terms.
Common questions
Can we replace only the outdoor unit on an older split system?
Only if a compatible unit using the same refrigerant is still available and the manufacturer lists it with your indoor coil. For R-410A systems that window is narrowing, and for R-22 systems it has effectively closed. New R-454B condensing units need a matching indoor coil or air handler. When the indoor half is also old, replacing both together avoids paying for refrigerant work twice.
Can the existing refrigerant lines be reused?
Sometimes. The lines have to be the sizes the new equipment's manual calls for at that length, free of kinks and leaks, and clean, and they must pass a nitrogen pressure test before the new equipment is connected. Lines buried in walls where they cannot be inspected, or lines from a system whose compressor burned out, are poor candidates. We test before promising reuse in a quote.
Where can the outdoor unit go if the roof is off limits?
On a concrete or composite pad at grade, on a wall-mounted bracket, in a service yard or on a lower roof, provided it has open airflow, service clearance and a piping route inside the model's length and lift limits. Property-line setbacks, noise near neighbours and the landlord's site rules also apply. In a multi-tenant plaza the rear service lane is the usual answer.
Is R-454B safe in a commercial building?
Yes, when the equipment is installed to its listing. R-454B is classed A2L, meaning low toxicity and mild flammability, and it is much harder to ignite than propane. Equipment built for it includes leak sensing and blower controls where the charge requires them, and the installation manual sets a minimum room area for the charge. For an owner, the practical effect is that field substitutions and mismatched components are not permitted.
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