Bryant HVAC logo with white gear and power symbol on dark gray background

This symbol is for an equipment ground- almost any time you see three lines parallel either horizontally or vertically- they will mean earth/ ground.



Here is an Outdoor Fan Motor where you can see it contains two windings, Start and Run. Also, in green is another symbol for ground

Pulled from an indoor ceiling cassette 40MBCQ

The chart/table on outdoor units have loads more of information so I will assist in clarifying.

These units are more complex and have more variables to consider.


*to keep things simple, we typically round close decimal numbers*


Min. Piping Length per each indoor unit- This is the minimum allowed amount of lineset for each indoor unit


Standard Piping Length per each indoor unit- this is the amount of lineset that has been “reserved” for each indoor unit for refrigerant charge purposes.


Max. outdoor-indoor height difference- how far you can separate the indoor from the outdoor vertically. Two labels are shown- IU indoor unit above OU outdoor unit and vice versa.


Max. height different between indoor units- if the indoor units are on different levels, then they should not exceed this amount of vertical separation amongst themselves.


Max. Length per each indoor unit- no indoor unit should have a lineset longer than this number. Do not exceed this number for any indoor unit lineset.


Max. Piping Length with no additional refrigerant charge- add together all of the lineset lengths for all the indoor units. If your lengths are above this number, then additional charge is needed.


Total Maximum Piping Length per system– when adding together all the indoor pipe lengths, this is the total length that the unit can support. Pipe lengths greater than this are not approved nor recommended.


Additional refrigerant charge- if your total lineset length is over the “Max. Piping Length with no additional refrigerant charge” amount, this is how many ounces per foot should be added to the unit for proper operation.


Pipe sizes: these show the pipe sizes with an asterisk (*) and then the quantity of those ports.

For example: from the 36K– 1/2 *2+3/8*2

This means 2 at ½ and 2 at 3/8.


In the event that the correct line set size is ran and it is not the same size as the hookup of this unit, use the factory supplied adapters to make the connections.

Steven Simmons

Technical Services Manager Southwest District

September 2, 2021

ABB Drives: How to Set Up on a Light Commercial System

Commercial HVAC

Have you seen an ABB Variable Frequency Drive or VFD for short?


Odds are if you have installed or serviced a light commercial HVAC system in the last few years then you have come across one of these drives. The first thing you will notice is that the VFD does not come with a key pad because under normal operations a keypad is not needed. Test and balance DO NOT need this keypad and they should make airflow adjustments with the sheaves on the motor.


Keypad Assistance?


When you first plug in the keypad it will prompt you for assistance. Choose “No”. The drives already have a program in them and they need a few parameters to be set. If assistance is chosen, it will make changes to the programing of the drive. If “yes” is chosen for assistance then you have to go to parameter 9902, change it to something other than HVAC and save it. Then edit the parameter back to HVAC and save it again. Go to parameter 1611 and select “Long View.” After that you can proceed with the parameter setup.


ABB VFD Models


Carrier/Bryant is utilizing two different models of the ABB brand drives on the light commercial platform: ACS320 and ACH550.


There are also two different Keypads: ACH-CP-B and CAR-CP-H.


The CAR-CP-H ONLY works on the ACH550.


The ACH-CP-B works on BOTH drives and is the newest keypad.


Your keypad model can be found on the back.

VFD Failure and Replacement


After a drive has failed and has been replaced you have two options when it comes to setting up the drive: Upload/Download or Manual Parameter Setup.


Upload/Download:


  • Can ONLY be used when you have the EXACT same unit model number to upload the parameters from as the unit model number that has the failed drive.


To UPLOAD:


Turn off- Press bottom left button

Menu- Press top right button

Par back up / Press enter on top right

Upload to panel—Press SEL top right

When finished: Press OK on top left

Press Exit on top left (press 2 times)

Turn back to auto (Press round button)



To DOWNLOAD:


Turn off– Press bottom left button

Menu– Press top right button

Par Back up / Press enter on top right

Download full set– Press SEL top right

When finish: Press OK on top left

Press Exit on top left Press 2 times

Turn back to auto (Press round button)



Manual Parameter Setup:


To perform a manual setup, use the book that came with the keypad to locate the page with your unit model number on the top and choose the page that has the correct drive number and motor model number. Double check that the HP and voltage are correct. Use the parameter settings and proceed:


To Access Parameters:


Turn off- Press bottom left button

Menu- Press top right button

Parameters / Press enter on top right

Select desired category 01-99/ Press SEL on top right

Select Desired Parameter/ Press EDIT on top right

Make needed changes/ Press SAVE on top right

Go to next Parameter OR Press exit to choose another category

After completion Press Exit on top left Press 3 times

Turn back to AUTO (Press round button)


Helpful Hints:


  • Drives MUST be “off” to make changes to parameters
  • Remember to put drive in “auto” BEFORE unplugging keypad
  • Categories are just the first two numbers of the parameter number


Example: Parameters 9905 and 9906 will be in category 99


  • Take pictures of the wiring of the controls on the old drive before unwiring it



Watch the Video Below for a Demonstration

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