Monthly Archives: October 2007

Series vs. Parallel Circuits

Electrical components can be wired together in one of two ways: series or parallel.
A series circuit is a single path for current through all of its components.
A parallel circuit is a different path for current through each of its components.

You will run into these two circuits in a HVAC zone control system or any electrical application.

These are a few things to remember when dealing with these circuits.

1) A parallel circuit provides the same voltage across all its components.
2) A series circuit provides different voltage across all of its components.

3) In a parallel circuit every load has a portion of the total current.
4) In a series circuit every load has the same current flowing through it.

5) To find the total resistance of all components in a parallel circuit, add the reciprocals of             the resistances of each component and take the reciprocal of the sum.
6) To find the total resistance of all the components in a series circuit, add the individual resistances of each component.

7) If one part of a parallel circuit is broken, or opened, current will still flow through parts of the circuit since there will be one or more paths for the current to travel.
8) If one part of a series circuit is broken no current at all will flow through the circuit.

Testing the Low Limit for a Z-300 control panel

What do you do when a Z-300 control board is calling for cooling yet the AC unit is not producing cooling?

While talking with a contactor while he was on the jobsite, he stated that his thermostat was calling for cooling, his Z-300 control board showed that cooling was being called for, and that the AC unit was not producing cooling. We went through a process of elimination and found out his low limit (suction line freeze stat) was not properly wired.

The final step of the testing was jumping the two (2) LL terminals on our control board. We had the contractor disconnect the low limit from the two (2) LL terminals on his Z-300 control board. Then he took a small piece of wire and jumped the two (2) LL contacts on his board to close the circuit. The AC unit ran properly. This shows that the low limit is the problem because when it was wired, it didn’t work; but when we jumped it, it worked.

We isolated the low limit, showed that the low limit was causing the AC not to run properly, and then rewired the low limit correctly. Everything worked perfectly after that.

If this test doesn’t solve your problem there are several other tests we can run. An inside sales engineer at Jackson Systems can usually walk you through the tests on the phone while you are at the jobsite. Feel free to give them a call to help solve all of your zoning needs.

Locking out the furnace when the outside temperature starts warming up

One of our customers called in and asked if we had a thermostat that had both an outside sensor and an inside sensor. He also wanted the outside sensor to lock out the heat mode of the furnace if the outside temperature went above 68 degrees.

There are many thermostats on the market with remote indoor and outdoor temperature sensor; however, they are not designed to shut off or lock out the HVAC system based on a selected outdoor temperature.

What we can do is suggest using a Ranco ETC Temperature control ETC-111000. You can wire this Ranco control in series with your indoor thermostat. You can then set your Ranco control with a high set point of 68 degrees. When the outside temperature rises above 68, the control will open the heating circuit thus ‘locking out’ your furnace, so your heat cannot run when the outside temperature is above 68. When the temperature drops below 68, the Ranco control will close, allowing your stat to turn the furnace back on in the heat mode.

This will stop anyone from running your furnace when it is warm outside and will save your customers money incase their kids feel cold and turn the heat up when it is 70 outside.

Jackson Systems, LLC Launches First Contractor-Direct Zone Control

Indianapolis, IN – Jackson Systems, LLC, an Indiana-based, award-winning HVAC manufacturer and wholesaler, announces the launch of the first zone control eCommerce Website for HVAC contractors. The site,, provides comprehensive resources for HVAC contractors wanting to buy zone control products online.

“We are offering a platform for busy contractors to do business ‘after hours’ and when it’s convenient for them,” said Tom Jackson, C.E.O. of Jackson Systems. “eCommerce makes it easy for contractors to buy what they want when they want it.  Of course all of our Inside Sales Engineers will be available as they always have to assist contractors via phone and email.”

The site offers over 200 technical articles and guides, and allows you to shop for control products any time once you establish an account. Items you may purchase include:

• Zone control products from Jackson Systems, including over 5,000 dampers in stock
• Other zoning products from Honeywell and Aprilaire
• Thermostats from Honeywell, Robertshaw, White-Rodgers, LuxPro, Aprilaire and PECO
• Commercial Controls from Jackson Systems
• Smoke detectors, Dual Fuel Kits, and Indoor Air Quality products
• Many other controls from leading manufacturers

To sign up for an account and begin purchasing online, please contact us at 1-888-652-9663 or e-mail us,

Planning for next year now

Well folks, it’s October. The holidays will hit, like tomorrow, and then it will be next year. Are you ready?

Look at your next 30 days. When in the next 30 days do you have three solid hours to sit down and really dive in to your next year planning? If you’re telling yourself, I don’t have three hours, then make three hours. You may not get everything you’ll do for 2008 accomplished, but you’ll get a start.

Here are three easy steps to get you started:

1 – First, set some priorities or goals for what you want to see happen in the next year.

2 – Then, put down some tactics to making those goals happen. Next, place it all in one big calendar.

3 – Once you have your ideas in your calendar, sit on it awhile and then review it again within the next two days. Refine as necessary.

Enjoy the stress-free task of month-to-month knowledge of what you’ll be doing to market your business in the next year.

Preparing for the winter cold

With winter just around the corner, property managers should to be aware of the risk of freezing pipes and water damage caused by tenants who turn the thermostat off when vacating or leaving their home for an extended period of time. This problem alone can lead to thousands of dollars in costly maintenance and renovation repairs each year.  Now, it can be totally avoided. The Never-Off-Stat™ thermostat can be used with all single stage heating and cooling systems, including electric heat. It is also available in a heat pump model. The thermostat does not require batteries and is truly user friendly. The Never-Off-Stat™ provides complete user control of heating and cooling set points with one very important extra function, when a tenant turns the thermostat off, the Never-Off-Stat™ will energize the heating system as required to prevent the space temperature from dropping below 55 degrees. If you are a contractor with property managers as your customers, tell them about the Never-Off-Stat™. It can give you a new project and save your customers lots of potentially costly damage.

Is your car more comfortable than your house?

Ask yourself this question: Is your car more comfortable than your house? If you are honest with yourself, many people will have to answer “yes”. This is due to no fault of your own. Natural laws keep us from staying comfortable in certain situations. Hot air rises and cold air falls. This leaves your second story of your home around 8 to 10 degrees warmer than the first level. Many homeowners/building owners would be more than happy to pay some extra dollars to eliminate this difference in temperature and become more comfortable. Several late model cars now have a feature called “dual climate control” added as a standard option. This feature allows the passengers to maintain a different temperature in their area than the driver’s area.  This analogy can be used to describe zoning as a basic concept as well. As contractors, you should ask your customers about their comfort and offer zoning as a solution. 

Zoning systems allow homeowners/building owners to install thermostats in various areas of their space to maintain different temperature settings. Along with a control panel and zone dampers, the owners can supply conditioned air to one area and shut it off to other areas while still sharing the same piece of HVAC equipment. The occupants are more comfortable and thus a happier bunch. Utilizing programmable thermostats, you can also experience energy savings by conditioning areas only when they are being used. Being more comfortable and saving some money is usually an attractive deal when offered. In most cases, zoning can help you achieve both if the system is properly designed and installed. 

So, is your car more comfortable than your house?  Investigate zoning systems to help solve this problem. You can find a way to achieve the comfort you are seeking. If we can accomplish this feat in our cars, then why not install it in the places where we spend the majority of our time?

The evolution of zone control

Zone control for residential and commercial applications has been in use since man figured out that heat generated from a fireplace or stove could be controlled within a given space by simply opening and closing doors, windows or ceiling grates. With the advent of forced air ducted central heating systems and later air conditioning, zoning was accomplished through the use of multiple pieces of equipment. Later, manual dampers were incorporated to control the distribution of conditioned air. As technology advanced, motorized damper systems were introduced that could be controlled by individual space thermostats. Although functional and simplistic in design, these systems could only limit the amount of heating or cooling within a given space and were dependent upon a master thermostat to control the equipment mode of operation. The first fully integrated zoning system was accomplished through the use of relays which provided a logical way for multiple thermostats, zone dampers and equipment to function in a proper sequence of operation. Diode/relay logic and microprocessor control panels are now the brains behind forced air zoning allowing compatible interface with all types of heating and cooling systems, high-tech digital thermostats and a multitude of control peripherals used to enhance system performance and individual zoned comfort. As with all technology, zoning has greatly improved over the last forty years. Systems are more versatile in application, easier to install, user friendly and provide optimal comfort and energy savings. Zone control has established a dominant position in the HVAC industry for both residential and commercial applications. It is a high profit installation for the contractor that greatly improves customer satisfaction and solves an age old problem: hot air rises and cold air falls. The benefits of zone control from a cost, comfort and energy savings stand point have great consumer appeal which is evidenced by rapid sales growth in both new construction and retrofit markets.

Commercial Zoning vs. Residential Zoning:

Even though the end result of commercial zoning is the same as residential, commercial systems require additional attention to the effects of heating and cooling load changes caused by lighting, equipment, people, solar radiation and wind. Compliance with building codes must also be addressed such as constant ventilation during occupied periods along with other Indoor Air Quality standards. Full modulating control of dampers or VAV diffusers are usually incorporated into the design to improve air distribution while maintaining individual zone temperature settings. Commercial systems also offer remote communications access for monitoring and control.

“Green Zone”

Green Buildings are designed to enhance operational performance, improve occupant health, save energy and contribute to a cleaner and safer environment. Zone control makes a Green Building greener by contributing to energy savings, system efficiency and employee comfort which leads to increased productivity. Zone control is rapidly becoming a standard part of Green Building design.

Jackson Systems noted as one of the fastest growing companies in Indiana

Indianapolis, IN – Jackson Systems, LLC, an Indiana-based, award-winning HVAC manufacturer and wholesaler, was selected as the fifteenth fastest growing company in central Indiana by the Indianapolis Business Journal on September 17, 2007. 

This is an exciting honor for us”, said Tom Jackson, C.E.O. “We have come a long way since starting in our garage in 1997. This inspires us to continue developing, manufacturing and distributing the best HVAC controls in the industry.” 

The Indianapolis Business Journal compiles an annual list of fastest-growing companies by examining the following criteria: revenue increases each fiscal year, revenue exceeded $1 million in fiscal year 2004, the company was an independent, privately held corporation, proprietorship or partnership (not a subsidiary or division) through December 31, 2006, the company was founded prior to January 1, 2004 and the company was based in the Indianapolis area. Information was verified by the companies’ outside accountants or provided tax returns. 

Jackson Systems has evolved from an entrepreneurial effort in 1997 of three employees to a growing small business of 30 employees and is approaching $10 million in sales. 


Jackson Systems, LLC is an award-winning HVAC company specializing in zone control. We design, manufacture and distribute controls for the heating and air conditioning industry. Our other areas of expertise include commercial zone control, thermostats and indoor air quality. Our headquarters are located in Indianapolis, Indiana. Jackson Systems serves both contractor and wholesale markets throughout the world.