Installation of a HITACHI airCore 700 central heat pump in Montréal-Est

An open-panel technical inspection before integration into the central system

The photo from this project in Montréal-Est shows a step rarely presented to homeowners: inspecting the outdoor unit before its final placement. The HITACHI airCore 700 central heat pump is still resting on its wooden transport base, while its large service panel has been removed. The two front fans, electronic boards, wiring, copper lines, and several components of the refrigeration circuit are then directly accessible to our technicians.

This preparatory inspection is important for a large central unit. It allows us to confirm that the equipment was not damaged during transport, that the internal connections are intact, and that the entire assembly matches the configuration planned for the building.

The project therefore does not begin when we connect the lines. It begins with a methodical check of the machine, the location, the duct network, and the electrical supply.

Why open the outdoor unit before installation?

In the photo, the right-hand technical section of the heat pump is fully visible. We can notably observe:

• the control boards;
• the terminal blocks and electrical harnesses;
• the copper refrigerant lines;
• the internal valves and fittings;
• the separation between the ventilation area and the technical area;
• the lower part of the chassis;
• the component supports and protective elements;
• the accessibility provided for future HVAC maintenance.

Before transporting the unit to its final location, we check that the components are securely fastened and that no pipe has any abnormal deformation. We also inspect the electrical connectors, visible sensors, board protection, and the overall condition of the chassis.

This step prevents us from completing an entire HVAC installation before discovering a problem related to transport or handling. On a central-system project, a problem discovered late can require dismantling ductwork, moving a heavy unit, or postponing commissioning.

A two-fan chassis that requires precise planning

The photographed outdoor unit has two stacked fans. This vertical format is associated with the higher-capacity configurations in the airCore 700 family. It provides the necessary heat exchange while maintaining a narrower footprint than a very wide unit.

However, the photograph does not show a nameplate that is legible enough to honestly confirm the exact capacity in BTUs. The outdoor format alone should never be used to identify the tonnage of a central heat pump.

The airCore 700 range includes several capacities and different types of indoor units. HITACHI documentation notably lists central air handlers of 18,000, 24,000, 30,000, 36,000, and 48,000 BTU, depending on the selected combination. The exact model of the outdoor unit, the indoor unit, and the AHRI reference must always be verified together.

This clarification is essential for three reasons:

1. two externally similar units may have different capacities;
2. energy performance depends on the complete combination;
3. eligibility for a subsidy is based on the model numbers and certification reference, not solely on the airCore 700 name.

Integrating a central heat pump into a building in Montréal-Est

A HITACHI airCore 700 central heat pump does not operate on its own. It must be paired with a compatible indoor unit and then integrated into a duct network capable of properly distributing air throughout all areas served.

For this project in Montréal-Est, our work included evaluating the factors that determine the actual result after installation:

• the capacity required by the building;
• the required airflow;
• the duct dimensions;
• the return-air surface area;
• the indoor unit location;
• the refrigerant line routing;
• condensate drainage;
• the available electrical capacity;
• the outdoor location and service clearances.

A high-performance machine cannot compensate for an undersized return-air opening, crushed ducts, or excessive static pressure. Comfort quality therefore depends just as much on the system design as on the heat pump itself.

Capacity determined by the building’s load

Capacity should not be selected based solely on floor area. A masonry building in Montréal-Est may have very different requirements from a newer home of comparable size located in Laval or on the South Shore.

We take several factors into account:

• wall and roof insulation;
• the number and type of windows;
• solar exposure;
• air infiltration;
• ceiling height;
• the presence of a basement;
• the number of occupants;
• heat-producing appliances;
• the distribution of rooms;
• duct losses;
• winter and summer design temperatures.

An oversized unit can cause excessively short cooling cycles. The temperature drops quickly, but dehumidification may become insufficient. The building may then feel cool without actually being comfortable.

An undersized unit may operate almost continuously during the coldest or hottest periods. The issue is not limited to energy consumption: some areas may never reach the desired temperature.

HITACHI airCore 700 technology adapted to Quebec's climate

The airCore 700 series uses an inverter-driven compressor and R-32 refrigerant. The inverter adjusts the system's operation according to the actual demand rather than operating only at full capacity or being turned off.

When the demand is moderate, the system can reduce its output. This modulation helps maintain a more consistent temperature, reduce sudden fluctuations, and limit repeated starts.

For HeatForce versions, HITACHI advertises a heating capacity maintained at 100% at approximately -15 °C and above 70% at -25 °C, without including in this graph the temporary losses associated with frost and defrost cycles. The heating operating range of the line also reaches approximately -25 °C.

These figures do not mean that every product combination delivers exactly the same number of BTUs at all temperatures. They describe the general behavior of the series. For a precise analysis, we consult the data for the installed pair, including:

• rated capacity;
• capacity at -8 °C;
• capacity at -15 °C;
• electricity consumption;
• COP at reference temperatures;
• SEER2;
• HSPF2;
• the building's balance point.

The role of defrosting during the winter

When a heat pump heats, the outdoor heat exchanger becomes cold. Moisture in the air can then form frost on the fins. The system must periodically initiate a defrost cycle to remove this buildup.

A proper installation must allow the water produced during this cycle to drain freely. The unit must not be placed directly in an area where water can refreeze beneath the chassis and form a block of ice.

The airCore 700 documentation specifies heating capacity for the lower pan to help prevent ice accumulation and support winter operation.

In Montréal-Est, we must also consider:

• the average height of snow accumulation;
• wind-created snowdrifts;
• ice falling from a roof;
• water from the gutters;
• the paths used for snow removal;
• the access required in the event of a winter service call.

An outdoor unit must never remain on its transport base

The photo was taken during preparation. The wooden structure visible beneath the unit is used for handling and transporting it. It does not represent the final installation base.

On site, the unit must be installed on a structure designed to support its weight, withstand the elements, and keep the equipment high enough above the ground.

Depending on the location, we can use:

• a wall-mounted metal bracket;
• a sturdy outdoor platform;
• a concrete base;
• stabilized slabs;
• a suitable base;
• compatible vibration-isolation components.

The choice depends on the building and the site. A poorly anchored platform can transmit vibrations. A slab installed on uncompacted soil can tilt. A support placed too low can expose the heat exchanger to snow or ice.

Clearances around the two fans

The two front fans must discharge air without encountering any significant obstruction. A fence, decorative panel, car parked too close, or objects stored in front of the unit can cause air recirculation.

In heating mode, the heat pump would then discharge cooled air in front of itself and could draw some of it back in. In cooling mode, it could draw in air that has already been heated. In both cases, operating conditions deteriorate.

We therefore check:

• clearance in front of the fans;
• space behind the heat exchanger;
• distance from the walls;
• clearance above the unit;
• the ability to remove the panels;
• access to the valves and connections;
• safe circulation around the unit.

A discreet location is not necessarily a good location. Above all, it must allow the system to breathe and the technician to work.

From an exposed outdoor unit to a winter-ready central system

The air handler and the ventilation network

The HITACHI airCore 700 platform can be paired with a central air handler. The documentation describes a five-speed ECM blower motor designed to provide the required airflow while reducing fan power consumption compared with certain conventional designs.

The indoor unit cabinet is approximately 20.5 inches wide, which can facilitate installation in certain mechanical rooms, basements, or tight spaces. An R-32 refrigerant detector is also factory-installed on the air handler.

However, these characteristics do not replace on-site adjustment. We must still determine:

• the appropriate fan speed;
• external static pressure;
• airflow in heating mode;
• airflow in cooling mode;
• filter compatibility;
• the plenum size;
• the configuration of the supplemental electric heating element;
• the control strategy.

Why measure static pressure?

Static pressure indicates the resistance the fan must overcome to move air through the network.

Excessive pressure can be caused by:

• a filter that is too restrictive;
• an undersized return air duct;
• ducts that are too small;
• tight bends;
• closed dampers;
• a dirty coil;
• a poorly designed transition.

Without measurement, the system may appear to be operating normally even though the actual airflow is insufficient. Possible consequences include noise, reduced capacity, increased consumption, and abnormal strain on the fan.

At AirGreen, we do not limit commissioning to checking whether air is coming out of the grilles. We seek to confirm that the air volume matches the machine’s capacity.

R-32 and the new safety requirements

R-32 has a lower global warming potential than R-410A, but it belongs to category A2L, meaning it is a mildly flammable refrigerant.

The installation therefore requires an appropriate work method:

• tools compatible with R-32;
• strict control of ignition sources;
• adequate ventilation of the work area;
• leak test;
• vacuum evacuation;
• compliance with load limits;
• protected connections;
• validation of the detector installed in the indoor unit.

The photo with the panel open makes it possible to see precisely why technical access must remain available. The components must not be enclosed behind a permanent structure that would prevent future inspection or repairs.

The refrigerant piping route

The airCore 700 product line offers considerable flexibility for certain complex projects. HITACHI indicates piping lengths of up to approximately 75 metres and a height difference of up to approximately 30 metres, depending on the model and applicable conditions.

However, these maximums should not be interpreted as a target. A shorter, better-designed route generally simplifies:

• evacuation;
• load calculation;
• line insulation;
• mechanical protection;
• oil return;
• future accessibility.

In Montréal-Est, some buildings require routes through a basement, garage, mechanical room, or narrow yard. We plan the route before drilling to avoid structures, electrical installations, gas lines, and areas where water infiltration could occur.

Final commissioning

After the mechanical installation, we perform a series of checks before handing the system over to the owner.

The procedure generally includes:

1. pressurizing the circuit with nitrogen;
2. leak detection;
3. controlled release of the test pressure;
4. evacuating the system;
5. checking that the vacuum holds;
6. opening the service valves;
7. validating the electrical connections;
8. starting the system in cooling mode;
9. starting the system in heating mode;
10. checking the defrost cycle when conditions permit;
11. measuring the temperatures;
12. checking the airflow;
13. checking the drain;
14. programming the controls;
15. explaining how it works to the owner.

The product line offers different control options, including the airPoint Room 700 wall controller. Wi-Fi integration with the airCloud Go app is also possible using the adapter provided by HITACHI. These accessories must be confirmed in the quotation, as they are not automatically included in all configurations.

The errors this photo helps explain

Close the panel without inspecting it

A pre-installation inspection can detect a loose connector, a displaced part, or a line damaged during transport.

Identify the capacity solely by the number of fans

Two fans indicate a large chassis, but not a certified capacity. Only the nameplate and AHRI combination provide the exact information.

Install the unit directly on the shipping wood

The pallet must be removed. It is not designed to withstand water, snow, and freeze-thaw cycles over the long term.

Placing the unit directly against a fence

The space must comply with technical clearances and allow air to be discharged.

Automatically reusing old lines

The diameter, condition, cleanliness, and compatibility of the existing lines must be verified before they are reused.

Neglecting the ductwork

A new heat pump will not resolve an improperly balanced system or insufficient return airflow.

Promising a subsidy without validating the combination

The series’ ENERGY STAR for cold climates certification is an advantage, but the financial assistance application must correspond to the outdoor model, indoor model, capacity at the required temperature, and applicable AHRI reference.

Potential subsidies and eligibility

Eligible versions of the airCore 700 HeatForce series carry ENERGY STAR for cold climates certification, which may provide access to certain financial assistance programs when all conditions are met.

Before providing the customer with a price, we confirm:

• the complete outdoor unit number;
• the complete indoor unit number;
• the AHRI reference;
• the heating capacity at the reference temperature;
• the installation address;
• the type of building;
• the criteria in effect when the application is submitted.

This verification protects the homeowner from an estimate based solely on an advertisement or the product’s commercial name.

A method applicable throughout Greater Montréal

This central heat pump installation in Montréal-Est also represents our work method for projects completed in Montréal, Laval, Longueuil, the North Shore, and the South Shore.

We attach equal importance:

• to sizing;
• to the condition of the ductwork;
• to electrical preparation;
• to location selection;
• to defrost water management;
• to compliance of the lines;
• to component accessibility;
• to the documented commissioning.

The photo of the open unit shows part of the work the homeowner does not usually see. Behind the panels of a HITACHI airCore 700, every connection, line, and component must be inspected before the unit is secured, connected, and commissioned.

It is this attention to the preparatory steps that makes it possible to achieve a clean, durable installation suited to the winters of Montréal-Est.