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Frequently Asked Fan Array Questions

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Fan FAQs:


What is included in an IntelliCUBE fan array?

The IntelliCUBE system includes EC, Permanent Magnet Synchronous Reluctance, or AC-powered fans, mounted in cubes and a control panel for single-point power and control. A number of options are available, including backdraft dampers and advanced controls.

Are the cubes standard sizes?

No, the cubes are built-to-order, and design specifically to fit the space inside the air handling unit. If there are access limitations, they can be accommodated in the design of the cubes.

How much do the fans weigh?

Depending on the fan and motor size, weight can range from about 40 lbs. to over 200 lbs. If a job requires smaller or lightweight fans, that can be accommodated during the selection process.

Is your wiring inside the unit waterproof?

Yes, all the wiring inside the unit is waterproof.

Do you use any sort of vibration isolation on the wall mounting fans?

No, the fans are mounted rigidly in the array. Studies have shown that isolators can actually increase the levels of detectable low-frequency vibration.

How efficient are IntelliCUBE fan arrays?

IntelliCUBE fan arrays save so much energy compared to traditional AC fan systems that they can pay for themselves with energy-saving in less than two years. Mainstream has developed an Energy Savings Calculator to quickly estimate the savings of switching to an EC fan array. This calculator has been approved by the ConEd engineering team to speed reviews for rebates and funding. Contact us for a free energy savings evaluation.


Doesn’t the signal lose power as it passes from fan to fan in the loop?

No, the signal doesn’t lose power, because the fans are simply reading the 0-10 volt signal, not using it up.

What if the customer wants to see what each individual fan in the wall is doing?

Each fan has an output so that you can send a signal from each fan back to the BMS if desired.

Do I need any special kind of inverter or transformer to step up or step down my building power?

No, standard AC power is brought directly to the back of the fan and all power conversion/speed adjustment happens within the actual fan motor

How is an IntelliCUBE fan array controlled?

An IntelliCUBE fan array can be controlled with the manual speed dial in the panel, or via a BMS signal. Additionally, with the premium control option, the fan array can be programmed to maintain a specified flow or discharge pressure setpoint.

Is there a single-point power connection for the fan array?

Yes. All the fans are wired back to a single power panel with a disconnect.

What control signals can you use?

The standard IntelliCUBE control panel has an input for a 0-10V or 4-20ma signal.

Do the fans run at different speeds?

No, all the fans in an IntelliCUBE fan array run in synchrony. However, if a specific job requires individual control of each fan, that can be accommodated.

Are the control panels rated to handle lightning or electrical surges?

Yes, surge protection is included in the control panels.

Is there any way to monitor a single fan in an array?

Yes, with the premium controls package, BACnet points including speed, status, warning, power, current and voltage, will be available for each individual fan in the array.

What is the enclosure rating of the control panels?

The standard control panel is a NEMA 1, and NEMA 3 is available for outdoor applications. Control panels are built-to-order, so if a specific rating is required for an application, that can normally be accommodated.

What is the SCCR rating of the control panel?

The standard SCCR rating for Mainstream control panels is 5KA SCCR, but it is not uncommon for control panels to be rated for 65KA SCCR. Control panels are built-to-order, so if a specific rating is required for an application, that can normally be accommodated.

How many inputs/outputs do you need in a wall with multiple fans?

Only one 10 volt input is necessary to run the fans.


What is the maximum static pressure you can achieve with an IntelliCUBE fan array?

An IntelliCUBE fan array can be designed to achieve over 11” of static pressure, which is more than enough for the vast majority of HVAC applications.

What is the CFM of a single ECM fan?

A typical ECM fan in an IntelliCUBE array will move as much as 8,000 CFM, although large ECM fans are available that can move as much as 20,000 CFM at low pressure.

What is the maximum CFM of an IntelliCUBE fan array?

There is no maximum CFM, as additional fans can be added. The largest fan arrays Mainstream has delivered have been around 300,000 CFM.

Is there a maximum number of fans in an IntelliCUBE fan array?

No, additional fans can always be added, depending on the space available.

What is the maximum power of an IntelliCUBE fan?

We offer a broad range of fans, up to 13kw / 17.5 HP, which means that the perfect fan and motor size can be selected for any operating point. This optimization increases efficiency and often reduces the number of fans required


What configurations are offered?

The IntelliCUBE system is offered in a variety of different configurations depending on your specific needs. Cube arrays, bulkheads, AHU sections and other configurations such as DWDI units are available.

What is included in the premium controls package?

The premium controls package includes a touchscreen interface, a BACnet gateway for monitoring several points for each individual fan, pre-wired whips, and airflow monitoring, which is calculated from piezo rings mounted on the inlets of the fans.

Can airflow monitoring be included?

Yes, airflow monitoring is included in the premium controls package.

How much pressure drop do backdraft dampers add?

Mainstream uses premium vertical blade backdraft dampers as standard, which add close to zero additional pressure drop.

Are backdraft dampers gravity-operated?

Typically backdraft dampers are gravity operated, however, motorized backdraft dampers are optional.

What benefits does N+1 redundancy provide?

For critical applications, N+1 redundancy provides peace of mind. By overbuilding the system with at least one additional fan to accommodate a potential fan failure, if a fan does fail, the system can still deliver fully without compromise. This feature is a must in environments such as hospitals, data centers, and other applications where failure is not an option.

Does the fan cube have a perforated liner for sound attenuation?

No. Although this can be offered as an option, it is rare that sound attenuation is included for a couple of reasons. First, IntelliCUBE fan arrays are almost always significantly quieter than the fans they are replacing. Being small, the higher frequency noise is easily attenuated in the unit. Second, a perforated liner can restrict airflow, increasing the RPM the fans need to run at.

Installation and Maintenance:

If the fans are daisy-chained, don’t you lose the whole wall if one of the fans in the series dies?

No, the signal touches each fan, however, the signal does not run through the fan, so you can lose a fan without affecting the others.

What if one fan in my wall goes down? How will I be able to tell this?

The 10-volt output can be sent to an alarm that will tell the user if one of the fans in the wall does fail. The fans also have internal alarm contacts that close/open if there is an internal electronic failure.

What if one of the fans in my wall does go down? Can I replace it?

Yes, you replace the entire fan module; motor, impeller, and housing.

What happens in the span of time from when my fan goes down to the new one arriving?

The other fans in the wall can ramp up to compensate for the lost capacity. Mainstream stocks these fans, so the downtime is minimal. Unlike the need for special rigging and balancing and alignment equipment (needed for very large fans), these fans arrive fully balanced and the entire module is changed out with four bolts (and the disconnection/reconnection of the electrical, of course).

Don’t you get back-flow through the inlet or outlet of the fan that is down?

Back-draft dampers can be installed that prevent this.
If the unit is not equipped with back-draft dampers, a factory-supplied blank-off plate can be inserted to cover the inlet of the existing fan to prevent back-flow.

What maintenance is required?

Zero. There is no replacing belts or shafts or greasing the bearings. Service will consist of inspection to confirm the fans are running.

How do you replace a DWDI fan with an array?

A double-width fan can be replaced with a standard fan array, although in some cases that is not the best option. If there is not enough room length-wise for a fan array (the inlets of the fans would be too close to the coil), or putting the fan section under positive pressure could compromise the integrity of the panels, a double-width fan array can be designed, to match the existing fan design while adding redundancy.

Do you offer site supervision or start-up?

Yes! We can offer site supervision or start-up for an additional fee, which is quoted per job and location.

How close can these fans be mounted to a cooling coil?

A rule of thumb is for a fan array to be installed a minimum of the fan diameter away from a cooling coil. Being that most fans are 24” or smaller, we recommend installing the fan array at least 24” from the face of a cooling coil.

What is the bearing life expectancy on these fans?

The life expectancy of the bearings varies depending on the fan selected and the conditions in which it is operating. However, typically we see a minimum expected life span of 10 – 13 years.

What happens if a fan fails?

In the unlikely event that one fan fails, the remaining fans can ramp up to help make up the difference. If N+1 redundancy was designed into the system (it is optional), the array will be able to maintain 100% of the airflow.

If one fan fails will they all fail?

No. The control wiring for each fan is home-run to the panel, rather than being daisy-chained from one fan to the next. As a result, a single fan failure will not affect the other fans in the array.

How can a failed fan be replaced?

If one fan in an array does fail, it is easily replaced without affecting the structure of the array. The fan can be four bolts in the corners of the mounting plate. Replacement fans are typically in stock.

Working with Mainstream:

What experience does Mainstream have working with EC fan and HVAC systems?

Mainstream has been working with EC fans, both in our AHUs and retrofitting existing AHUs, for over a decade. Our experience with air-handling equipment extends back to 1992.

What information do you need to quote?

Performance data (airflow and static pressure), dimensions of the space inside the unit, and voltage. Additionally, information such as motor data, unit or fan data or model numbers, and photos can be very helpful.

What is included with a quote?

Selections, included options, submittal data, drawing, performance data, and electrical data are included with IntelliCUBE fan array quotes.

How long does it take to get a quote?

After a quote request is received, Mainstream can return comprehensive quotes on the same day.

What is the warranty?

All components of an IntelliCUBE fan array are covered under a 2-year parts and labor warranty. See Mainstream’s IntelliCUBE Limited Product Warranty for details.

What are your lead times?

Thanks to a robust supply chain, Mainstream’s lead times remain competitive despite disruptions to supply chains throughout the industry.

How do you ship these?

IntelliCUBE fan arrays are shipped broken down into individual cubes, with the fans mounted inside. With a bulkhead design, the fans are shipped loose, to be mounted in the field.