Monthly Archives: November 2007

Using a night thermostat on a zone system

Some customers, especially commercial customers, will want to use a night thermostat to set back all the zones in a zoning system to allow for occupied and unoccupied temperature scheduling of the building.

The components needed are a night thermostat, a 7-day time clock, and an override timer. Occupied and unoccupied scheduling can be accomplished with most zoning systems by interrupting the “R wire” between the zone control panel and the equipment. Other zoning system control boards like a Jackson Systems’ Z-2000 have terminals built into the boards for these connections. The time clock is set to open the equipment control circuit at night which will lower temperature in the case of heating (and raise the temperature in the case of cooling) to the set point on the night thermostat. The override timer is used to override the night thermostat and give control back to the zone control system.

As for wiring of the components, this depends on the control board used.  The time clock, night thermostat, and override timer must be in parallel.  Either the board must accomplish this, so you will see a separate terminal for each device, or you must physically wire the three devices in parallel.

Using these components will allow for even greater energy savings for the customer.

Troubleshooting a Z-300 Panel

Listed below are some steps to help technicians troubleshoot a Z-300 panel from Jackson Systems.  These steps are a quick and easy way to narrow down where the problem area might be.  Here are the basic steps to start with:

1. Verify that the power light is on.  If not, check the fuse marked “PC Board” to insure that it is not blown. 
2. Verify that the Heat or Cool light is on.  If not, make sure that at least one zone is calling for heat or cooling. 
3. Verify that the fuse marked “Contacts” is not blown. 
4. The fuse marked “Contacts” protects the relay contacts on our board and is wired in series with the “R” wire from the furnace.  The fuse marked “PC Board” protects the pc board, thermostats, and damper motors.  By determining which fuse is blown, you will know which area to begin to work with. 
5. If no fuses are blown, jumper out the low limit stat terminals marked “LL” and the high limit stat terminals marked “HL”.  These limits are used to stop heating or cooling and not the fan.  If the equipment comes on when jumped, there is an issue with the limit. 
6. Check to see if the thermostat and damper(s) are serving the appropriate zone by putting all stats in the heat mode.  Then, turn all stats down and call for heat at each zone.  Verify that the proper thermostat and damper is supplying the appropriate area. 
7. Verify that the HVAC equipment will run by jumping across the “R” and “W” terminals and then across the “R” and “Y” terminals for the equipment.  The terminals are located on the terminal strip on the right hand side of the Z-300 panel.
8. Verify that the thermostat is operating properly by disconnecting the thermostat wires from the panel.  Then, take a small piece of wire and jumper across “R” and “Y” and then across “R” and “W”.  The appropriate Cool or Heat lead lights should come on at the panel.  If they do, there is a problem with the thermostat or the wiring going to or from the thermostat. 
9. Verify that the Z-300 control panel is not being powered by the transformer in the furnace.  Typically, the furnace transformer does not have enough VA to power the panel and dampers.  We also recommend a separate transformer for our system so that we provide enough VA and we can separate our panel from the rest of the equipment. 
10. Know that our panel output terminals are the same as the terminals on a thermostat.  They are just a set of dry contacts. 

Hopefully these steps can eliminate areas that are found not to be the problem.  Through the process of elimination, we can narrow down the cause of the problem and more accurately diagnose it.  After these steps are taken, you can generally name the source of the problem and work on the solution. 

What I am thankful for?

Such a simple question, but such a long answer.  If I listed everything that I am thankful for, it would take up many pages, so I will just list some of my top ones.

I am thankful for all those that have served and are currently serving in the United States military.  I am humbled by their dedication and service.  Each of them holds a special place in my heart.

I am thankful for all the blessings that God has given me.  Without getting religious, my faith in God is important.

I am thankful I live in the United States of America.  I can pursue my dreams and have the freedom to do what I enjoy.

I am thankful for my family.  I have a loving wife and two great children (ages 5 and 7).  I have incredible parents (who happen to be my business partners) and 3 wonderful brothers.  We all still get together almost every Sunday night for dinner.

I am thankful for my co-workers at Jackson Systems.  Eleven years ago I could not image having almost 30 people working with me.  Each of them is an extremely important part of the success of Jackson Systems.

I am thankful for our customers.  While we are not their largest supplier, they are always appreciative of our service and products.  I think our customers relate well to Jackson Systems.  They know we are a small business just like them trying to take care of the customer the very best we can.

I hope you have a truly wonderful Thanksgiving holiday.  We all have much to be thankful for.


Tom Jackson

Changing Z-300 fan default mode

The Z-300-HC control board is a single heat/single cool zone control board that defaults to the dampers being open when there is not a call for conditioned air (heating or cooling).  We call this ventilation mode.  In some applications you may want to have zone #1 damper closed and not go into ventilation mode after the zone is satisfied.  In order for zone #1 not to go into ventilation mode, you need to cut the jumper between the first and second relay on the control board.  You then need to add a jumper wire between terminals 4 and 6 on the T5 terminal strip.  Doing these two steps will close zone #1 damper after the zone is satisfied.

Anticipators on Thermostats

The reason heat anticipators are not required on solid-state, microprocessor based thermostats is that the thermostat control algorithm is designed to track the temperature rate of recovery in the space and automatically adjust the equipment on/off time (cycles per hour) to achieve the thermostat setpoint without over-heating the space. A heat anticipator on a mechanical thermostat is an adjustable bi-metal devise (spring) that receives a small amount of current from the furnace gas valve. The heat that is generated by the current flow changes the distance between the thermostat contacts. Therefore, the thermostat opens the contacts and shuts off the equipment prior to reaching setpoint so that the residual heat from the furnace does not cause the space to overheat. It still happens due to the fact that mechanical thermostats are very slow to react compared to solid-state controls that can provide immediate response to changes in temperature. There is more physics involved but hopefully this will provide some insight.

Using an Isolation Relay to loop multiple Retro Dampers

With the slow down in new residential construction many contractors are looking for ways to keep sales growth moving forward.  One way they are doing this is to offer their expertise to homeowners who are looking to upgrade their existing whole house HVAC system to a zone control system.

We recently had a contractor call us and said they are retrofitting a house with our Z-300-HC zone control using it for 2 zones.  He wanted to use 9 retro dampers in zone 1 and 12 retro dampers in the current duct work on zone 2.  Being that he was an experienced contractor and knowing that Jackson System’s retro dampers uses 3.8VA each, he knew he couldn’t use a 70VA transformer to power our control panel, zone 1 and zone 2.  He called us for help.

We suggested using an Isolation Relay and a separate 120v/24v 75VA transformer for zone 2.

We walked the contractor through the following steps.  Using a Jackson Systems RY-1-HB relay(24v coil NC-C-NO contacts) we had him wire the two contacts marked 24v coil on our relay into the D and D contacts on the zone 2 terminal strip on his control board.  Next we took the common wire from our second separate transformer and wired it into the C contact on the relay.  We wired the 2nd common of the transformer into the common of the 1st retro damper of zone 2.  We then ran a wire from the NO contact on the relay into the NO contact on the 1rst Retro damper and the wire from the NC contact in the relay into the NC contact on the 1st retro damper. 
Now we are almost done.  We wire the remaining 11 dampers in zone 2 in parallel to the 1st retro damper. 

What we have accomplished is powering the zone 2 dampers with its own transformer and tying them all into the Z-300-HC control board using an Isolation Relay.  We have saved the contractor and homeowner money by not having an additional control board with a very small additional cost of a transformer, a relay and wire.

The next time you are retro fitting an existing HVAC unit remember there is usually a way to accomplish what you want that is quick, easy, and inexpensive to install on the job.

Download wiring_diagram_isolation_relay_with_multiple_retro_dampers.pdf

Interfacing Jackson Systems Comfort System with a Honeywell IAQ

When installing Jackson Systems’ Comfort System with a Honeywell IAQ thermostat, there is one step that a contractor needs to be aware of during installation and setup.

The IAQ (Indoor Air Quality) thermostat must be configured properly through the Installer Setup program. Setup function 0110 is for zone number.  This often confuses the contractor in thinking that the thermostat needs to be assigned a specific Comfort System zone. This only applies when using the IAQ thermostat with a Honeywell IAQ zoning system.

When using a Jackson System Comfort System you will want the zone number for all IAQ thermostats to be set to 0 as they do not communicate with a Comfort System and should be configured as stand-alone thermostats.

E Contact on a Thermostat

Some contractors have come across an E contact on a heat pump thermostat.  This thermostat is using the E contact for emergency heat.

Many zone boards including Jackson Systems Comfort System boards do not have a corresponding E contact but run the emergency heat through the W (auxiliary) contact.

What we would do in this situation is jumper the E contact and the W contact at the thermostat.  Then run a connection from the W contact at the thermostat to the W contact at our control board.

This way in the case of emergency heat or the stat asking for auxiliary heat, the control board will bring on the furnace heat.