Section Ix Unit Data, Airflow Selection | Johnson Controls AV*(C) Series

536636-UIM-D-1211

SECTION VIII: AIRFLOW AND COMFORT SETTING SELECTION

AIRFLOW SELECTION

The airflow and comfort setting selection jumpers must be set properly at the time of installation for proper system operation. Place jumpers in the proper locations based on the information shown in Table 16 and Figure 11.

Inputs to air handler control board are passed to the motor which deter- mines the target CFM to be delivered. The following inputs will produce the CFM per the appropriate table and selected tap settings.

NOTICE

Incorrect airflow and comfort settings may result in decreased system efficiency and performance.

These variable speed air handlers are designed to deliver constant air- flow (CFM) regardless of the external static pressure (ESP) in the duct- work. Therefore, if too many supply registers are closed, a filter becomes clogged, or there is a restriction in the ductwork, the motor will automatically operate at a higher speed to compensate for the higher ESP. This may result in a higher operating sound level.

To Set Cooling Airflow:

Refer to the outdoor unit technical guide for the recommended airflow with the matching evaporator coil. Refer to Table 16 for the possible high speed cooling and heat pump airflow selections.

Find the recommended system airflow in Table 16 for the installed air handler model.

Select the COOL airflow you need from Table 16. Set the COOL and ADJUST Jumpers on the control as indicated in Table 16.

To Set Heat Pump Airflow:

The heat pump airflow setting is the same as the cooling airflow setting. No additional airflow setting is required. However, you must set the MODE jumper to the HP position for proper system operation (See Fig- ure 11).

To Set Electric W1 Heat Airflow:

The blower speed required for 1st stage electric heat is different than cooling. Refer to Table 16 for the possible CFM selections. Refer to Table10 for the minimum required airflow for the electric heater installed. Find the desired airflow in Table 16 for low heat. Set the HEAT jumper on the control as indicated in Table 16.

To Set W2 Electric Heat Airflow:

Airflow for any W2 input, which is for Stages 2 & 3 of electric heat, is the indicated CFM for high heat tap selection on Table 16.

DO NOT change the ADJUST tap position on the control as this will change your cooling airflow previously selected.

Fan Only CFM:

When the connection is made from "R" to "G", the fan only mode is acti- vated. In this mode, the airflow will depend on the position of the CONT Fan jumper. In the “H” position, the blower will deliver 85-90% of full capacity. In the “M” position, the blower will deliver 60-65% of full capacity. In the “L” position, the blower will deliver 30-35% of full capac- ity.

Blower Ramp-Up /Ramp-Down:

To minimize the sound made by the blower when it speeds up or slows down, the blower will slowly ramp up or down from one speed to another. Changes in blower speed during A/C or heat pump heating can take up to 30 seconds. Changes in blower speed during electric strip heating can take up to 15 seconds.

COMFORT SETTINGS TABLE 6: Comfort Setting Selection

DELAY TAP	COMFORT SETTING

A	Normal
B	Humid
C	Dry
D	Temperate

Normal

The normal setting provides a ramp-up from zero airflow to full capacity and a ramp-down from full capacity back to zero airflow.

Humid

The humid setting is best-suited for installations where the humidity is frequently very high during cooling season, such as in the southern part of the country. On a call for cooling, the blower will ramp up to 50% of full capacity and will stay there for two minutes, then will ramp up to 82% of full capacity and will stay there for five minutes, and then will ramp up to full capacity, where it will stay until the wall thermostat is sat- isfied.

Dry

The dry setting is best suited to parts of the country where excessive humidity is not generally a problem, where the summer months are usu- ally dry. On a call for cooling the motor will ramp up to full capacity and will stay there until the thermostat is satisfied. At the end of the cooling cycle, the blower will ramp down to 50% of full capacity where it will stay for 60 seconds. Then it will ramp down to zero.

Temperate

The temperate setting is best suited for most of the country, where nei- ther excessive humidity nor extremely dry conditions are the norm. On a call for cooling, the motor will ramp up to 63% of full capacity and will stay there for 90 seconds, then will ramp up to full capacity. At the end of the cooling cycle, the motor will ramp down to 63% of full capacity and will stay there for 30 seconds, then will ramp down to zero.