High-end heating and cooling equipment offers unsurpassed levels of comfort and efficiency, thanks in part to their sophisticated controls. Manufacturers work hard to ensure their controls not only make life easier - and more comfortable - for the end user, but help contractors save time and work more effectively in the field. Below is a round-up of some of the integrated control systems that can be found on manufacturers’ high-end systems.


iQ Drive® systems utilize a patent-pending communicating controller. Installed inside the home, the controller “talks” to the outdoor unit, assessing the cooling load of the space and using the information to compute and communicate the ideal speeds to the system’s inverter and indoor fan. The inverter and controller also get continuous feedback from the compressor in case further adjustments are necessary. This communication occurs multiple times every second for nearly constant interaction.

If paired with an air handler, the controller also calibrates the indoor blower on a periodic basis, performing a load calculation on the duct system and measuring resistance to airflow in order to learn the duct characteristics of the home and perform at optimum efficiency. When matched with a high-efficiency furnace, the controller communicates with the blower, and indirectly with the furnace controls, to achieve the same flexible result.

The controller also has diagnostic capabilities, alerting the homeowner when a service call is needed and providing service technicians with information to help them quickly assess the problem. The dealer can preload contact information into the controller that will flash if a service call is needed. When a service technician first enters the home, the first stop is the controller, not the unit.

This controller is utilized on 24.5 SEER iQ Drive air conditioners, 22 SEER iQ Drive heat pumps, and 97-percent-plus AFUE iQ Drive modulating gas furnaces and is available in the Maytag, Broan, Frigidaire, NuTone, Tappan, and Westinghouse brands.


The icomfort™ communicating system makes the contractor better at what they do. Installations are easier because there are only four wires, and set-up is done at the icomfort Touch thermostat instead of using dipswitches at the indoor unit. Setting up an icomfort system is similar to installing software on a computer - it’s a linear process in which the control walks the technician through the entire process of adjusting system parameters.

An icomfort system tests itself and offers real-time diagnostics so technicians know the system is working correctly before they leave the job. If there’s ever a problem with an icomfort installation, the system offers information-rich diagnostics and error codes so the technician knows what the problem is before arriving for the service call. The icomfort Touch thermostat has a full-color touchscreen control that homeowners love, said the company. It looks like the smart phone they’re already using, and it’s just as simple to use.

The icomfort communicating system will make homeowners comfortable, save them money, and make dealers more profitable, said the company. Currently, icomfort is available on Dave Lennox Signature Collection products, including the G71MPP furnace, the CBX32MV and CBX40 air handlers, and the XC/XP17 and XC/XP21 air conditioners and heat pumps.


When combined with Carrier’s most energy-efficient products, the Infinity® Control provides customers with optimal performance of their equipment and optimal comfort. When matched with the proper system components, the Infinity Control is capable of controlling temperature, humidification, dehumidification, ventilation, IAQ, and airflow.

The Infinity system control can be expanded with a wide array of options, allowing homeowners to utilize technologies like IdealHumidity™, ComfortHeat™ and IdealComfort™. These predictive features ensure optimal comfort levels by adjusting airflow and humidity levels automatically. The control’s integrated humidity and IAQ monitoring capability provides on-screen notification to the homeowner when filter or humidification pad replacements are needed. The control has seven-day programming with two or four periods per day. In zoned configurations, the Infinity Control has programmable fan options by period and zone. Other advanced features include optional remote access capability available through the SkyTel network or over broadband Internet. Using remote access, the homeowner can program and/or monitor HVAC equipment from any computer or web-enabled device.

For the contractor, an Infinity system control means there is only one wiring diagram. A four-wire, color-coded connection makes it easy to connect all the pieces, and there is minimal or no set-up for most installations because the control is self-configuring. It has 83 points of scripted HVAC diagnostics to help the contractor save time and money by pinpointing system faults. When configured with remote access, it even allows the contractor to access system diagnostics in advance of a service call so the contractor can know what the system needs before ever walking in the door.


Daikin’s high-end controls are designed to optimize efficiency for the user and simplify the HVAC contractor’s job. The integrated controls are complex enough to constantly monitor pressure and temperature throughout the system and prevent, resolve, and diagnose service issues as well as indicate when filters need to be cleaned.

Daikin’s controls, available in some variation on all product lines, feature many set-up functions such as field setting assistance, comfort and setback temperature scheduling (in both occupied or unoccupied periods), button prohibit functions, and error history.

When an unexpected operation is observed, the control system reduces the compressor speed gradually so the system can return to the normal status automatically. To help contractors quickly repair service issues, Daikin controls report an alarm status and code, indicating one of up to 200 different malfunctions. Contractors can see a step-by-step diagnostic flowchart for each code in Daikin’s service manuals.

Contractors can also reference the status and code through a remote controller, which is connected to the indoor unit, or an optional centralized controller, which can observe the entire system. The information can also be transferred to a building automation system through Daikin BACnet or LonWork interface.

Goodman Global Inc.

With the ComfortNet Communicating Control system, an HVAC technician will never need more than four control wires to connect a gas furnace or air handler to the control system. (Wiring can be reduced to just two wires by installing the transformer included with the control kit in the condensing unit.)

The ComfortNet system vastly simplifies installation, setup, monitoring, and diagnostics between the control unit and Goodman- and Amana-brand gas furnaces (two-stage, variable-speed); air handlers; and 16 to 18 SEER two-stage air conditioners and heat pumps. The control unit actively monitors and analyzes the entire HVAC system for any irregular conditions, and if detected, the control will take appropriate action and display the results in the diagnostic menu on the ComfortNet control unit. The unit even alerts the homeowner to call for service.

Installation and setup become far easier with ComfortNet’s auto-configuration. Once the low voltage wires and the ComfortNet control are installed, a search for the indoor and outdoor components of the systems begins. Then, by means of shared data programming, the control system will automatically setup the airflow and all operating characteristics based on the capacity of the indoor and outdoor system components.

Programming is simplified with a large, 12-square-inch touchscreen display. The ComfortNet’s intuitive menu, with audio prompts and color-coded temperature touch keys, allow for quick adjustment. Other ComfortNet features include dedicated programmable or non-programmable modes, a selectable energy management recovery program and battery backup.


Comfort Control²System, a serial-communications control board designed with contractor satisfaction in mind, is available on high-end residential products, including condensing units, heat pumps, furnaces, and air handlers. The control board offers an easy four-wire installation, as well as a detailed display of the unit’s operating history. The serial communications capability allows the indoor units to recognize the outdoor unit and establish default design characteristics for that specific unit. This eases installation by eliminating dip switches previously required for these attributes.

Located on both indoor and outdoor units, the Comfort Control²System control board features an easy-to-read, dual seven-segment LED display that provides up to 37 individual fault codes, reducing servicing time and guaranteeing an accurate diagnosis. On the heat pump designs, the innovative control board also features a defrost component, eliminating the need for a secondary defrost board and reducing the number of individual parts that need service or maintenance.

High-end commercial products are available with ClearControl™, which is factory mounted and wired in 3- to -25-ton package units. ClearControl is a solid-state microprocessor-based control board that provides flexible control and extensive diagnostics for all unit functions.

ClearControl allows contractors to take advantage of advanced diagnostics and communications via an LCD screen located on the control board. ClearControl features a 16 by 2 character LCD display and a five-button keypad for local configuration and direct diagnosis of the system. The easy-to-read LCD screen can report on over 100 different conditions to positively impact ease of service, reliability and product longevity.

LG Electronics

An array of integrated controls solutions is available through the Multi-V product category, a variable refrigerant flow (VRF) system that delivers economic and performance benefits over individually sourced and applied devices. Internally, all Multi-V indoor fancoil units and outdoor condensing units are factory equipped with advanced, microprocessor based digital controls for the management of refrigerant flow throughout the system’s piping network. This ensures precise space temperature management and continuous operation at optimum efficiency points during part load conditions.

Externally, LG’s lineup of individual zone controllers and advanced central control solutions including the LCD touch screen based AC Smart™ and web-enabled ACP™ seamlessly integrate into single or multiple system applications through an innovative two-wire bus architecture based upon the robust and field proven RS-485 standard.

Mechanical contractors experience immediate benefits of this true multipoint network through reduced material cost and elimination of subcontract controls expenses, since this is a controls solution they can install and maintain on their own. When project specifications call for the integration of Multi-V systems into a facility’s existing or planned automation system, LG offers open protocol gateways that adhere to the standards based upon both BACnet and LonTalk protocols. Finally, efficiencies are brought to the diagnostic and troubleshooting process as well. LG’s embedded control logic provides the service team with specific and detailed error code profiles should a system anomaly develop, helping to pinpoint the source of trouble and accelerate remediation.


ComfortLink™ II integrated control systems can be found on the XC95m high efficiency modulating gas furnace and XL20i air conditioners and heat pumps. The use of ComfortLink II control systems in these products delivers Trane Tru™ efficiency - meaning customers receive the maximum efficiency expected from their properly configured and installed Trane ComfortLink II high-performance system. This is achieved with perfectly matched integrated digital controls that constantly communicate with each other.

The integration of communicating controls allows the components to automatically be self configured at set-up, perform self-diagnostics, and continually monitor themselves for proper airflow and humidity control. The XL20i outdoor unit control board has Charge Assist™, which saves dealers time and provides peace of mind for homeowners. With a simple press of the Charge Assist button located on the XL20i’s integrated control board, the system will be started and placed into cooling mode (without entering the home) and automatically checks for the correct refrigerant level. With an optional Charge Assist tool (electronic refrigerant valve), the system automatically charges to within 0.1 of the factory specified refrigerant charge. The simple three-wire indoor and two-wire outdoor low voltage wiring speeds up the time to install two stage systems.

On the XC95m modulating gas furnace, the XL900 ComfortLink II comfort control communicates both the desired room temperature and the actual room temperature to the XC95m’s integrated control board. The XC95m draft inducer speed is increased or decreased based on the information communicated from the XL900 control and the gas flow is also directly linked to this change in speed. As the draft inducer speed increases or decreases, the gas valve flow rate is also varied. This ensures that the combustion efficiency is correct and the AFUE level is delivered at all firing rates.

Sidebar: Electronics

The convergence of megatrends in the HVAC and smart energy industries is putting new pressures on contractors and technicians to serve their customers more accurately and efficiently in the field. Federal minimum efficiency levels are increasing at the same time that utility companies struggle to keep up with energy demands and homeowners seek relief from higher energy costs. And all this comes along with a shortage of qualified contractors to install and service HVAC systems as more of the current workforce continues to retire and fewer trained technicians enter the field.

Given these dynamics, the development of multi-staged variable speed equipment and smart energy devices have become top priorities for their respective industries, advances that open the door to valuable information, which in turn can enable higher efficiency systems, improve overall comfort, and reduce burdens on contractors.

Solving the problem of fragmentation within the HVAC and energy management appliances industries requires a common language. Developing that language is the goal of the ClimateTalk™ Alliance, a consortium of HVAC manufacturers and companies, focused on the development of an open communications platform. ClimateTalk specifies the standards for the:

• Interoperability of diverse systems allowing the free exchange of information between the components of different manufacturers;

• Interchangeability of these components without change in form, fit, or function; and

• Compliance testing ensuring expected operation.

ClimateTalk features are easy to install, operate, and repair. For systems with high-end integrated electronics, ClimateTalk helps field technicians diagnose problems quickly - and eventually even before arriving at the home - reducing the amount of time spent on each service call and driving down labor costs. Equally important, they’re able to resolve the problem more accurately, delivering the exceptional service that satisfies customers and protects their reputations. And with interoperability and backward compatibility to non-communicating devices, they have the added benefit of flexibility, using components already on their trucks.

Contractors are recognizing these business advantages. Jim Stanch and Jeff Stanch, owners of Nogginhaus LLC, agreed, “We should support manufacturers that adopt an open communications protocol like ClimateTalk. By demanding ClimateTalk-enabled equipment from our vendors, we help ensure our ability to offer a high level of service to our customers without increasing costs. It’s also a unique way to help solve our technician shortage so that we can focus more on opportunities to grow our business.”

Publication date:06/21/2010