Roof Top Unit Control Boards

Over the years, as technology changed and new products were introduced, we have made changes to the various control boards we have used in our roof top units.

For many years we used a simple “lock-out relay” board — one for single stage cooling and one for 2 stage cooling.  With the addition of diagnostic flash codes to boards, these boards were replaced with ourSimplicity®line of boards.

The Simplicity® 1A board was introduced with our Predator line of units back around 2000.  We still used the “lock-out” relay board on the large and small Sunline units.

In 2003, we started to use the Simplicity®1A board in the small Sunline units and continued to use it until  August, 2006 when the Simplicity® LITE was introduced.  We also started using the Simplicity®1A in the larger Sunline and Magnum units in 2003.

Because we have used the Simplicity® LITE and  1A boards in the Small Sunline units, it is VERY IMPORTANT to look at the serial number of the unit to make sure you get the correct board if ever you have to replace it.

I have attached a “decoder” for the various boards at the end of this posting.  Be sure to look it over and note the serial number/dates for each board.  By using this, you can be pretty sure you will get the correct board if ever you need it.


About yorkcentraltechtalk

I have been in the HVAC industry most of my life. I worked 25 years for contractors on anything from residential to large commercial boilers and power burners. For the past 23+ years I had been employed by York International UPG Division ( a division of Johnson Controls) as a Technical support/Service Manager but I am now retired. One of my goals has always been to "educate" dealers and contractors. The reason for starting this blog was to share some knowledge, thoughts, ideas, etc with anyone who takes the time to read it. The contents of this blog are my own opinions, thoughts, experiences and should not be construed as those of Johnson Controls York UPG in any way. I hope you find this a help. I always welcome comments and suggestions for postings and will do my best to address any thoughts, questions, or topics you may want to hear about. Thanks for taking the time to read my postings! Mike Bishop
This entry was posted in HVAC Tech Support. Bookmark the permalink.

6 Responses to Roof Top Unit Control Boards

  1. Muhammad Saleem says:

    York roof top package unit showing fc3 error code how I do solve this

  2. Jim Clarke says:

    I just installed a ZF072N10N2AAA4 5 ton rooftop. The co2 detector that came with this doesn’t wire in according to the wire schematics. The economizer is different and so are the controls. This has a Honeywell digital control not shown at all in the drawing. Is there a sight that will have a wiring diagram for this?

    • on the main Simplicity SE control board there are provisions for a Shut Down (SD) circuit.Smoke detectors get wired into that circuit to “kill” the entire unit if they trip. The Honeywell Jade control or the Johnson solid state control have nothing to do with shut down of a smoke detector — that is the main board function
      You can check with your distributor for specific wiring diagrams

  3. Ray says:

    Very new roof top unit 2 compresors systems # 1 is emty no charge of freon unit 2 charge normal ??? Please help can i bypass system one ?? 847 445 622 or email me at

    • What is the model number? Different units use different control boards. Depending on which unit you have will determine the control board.
      Did you find the ,”leak” and repair it? If you fix it and weigh in the charge, you’ll be able to get the unit operating.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s