Carrier The Ultimate Guide to Air Flow Adjustments and Fire Safety for Moduline Air Conditioners

Fig. 82A Ð NO Con®guration for Fire Safety

Fig. 82B Ð NC Con®guration for Fire Safety

Fig. 83 Ð Fire Safety Switch Floor Layout

AIRFLOW ADJUSTMENT

Each 37HS volume controller is equipped with a maxi- mum cfm lever for setting the required unit air¯ow in the ®eld. The lever is located at the bottom of the controller. See Fig. 84. The controller has a star wheel located at the top of the controller for setting the minimum air¯ow. The star wheel is also shown in Fig. 84.

Maximum Air¯ow (Cfm) Adjustment Ð The 37HS maximum air¯ow adjustment lever is common to all sizes and is divided into levels of percent cfm. Table 16 shows the unit air¯ow that will be obtained by each lever setting for each unit size.

Table 16 Ð Maximum Air¯ow Settings

LEVER SETTING		UNIT AIRFLOW (CFM)
(% CFM)	37HS1		37HS2	37HS4
120	120		240	480
100	100		200	400
80	80		160	320
40	40		80	160

The maximum cfm is the unit air¯ow obtained when the thermostat is calling for full cooling in a VAV system; it is the design cfm for the space conditioned by the unit or units regulated by one controller.

To set maximum cfm with zero minimum cfm:

1.Set diffuser or wall thermostat for maximum cooling.

2.Turn the minimum cfm star wheel counterlockwise until the internal stop is reached. Do not attempt to override stop. (Minimum cfm has been set at zero, and the unit will turn off when required.)

3.Adjust maximum cfm lever to desired percent cfm.

Minimum Air¯ow (Cfm) Adjustment Ð Some ap- plications require both a design maximum cfm and a mini- mum cfm. The 37HS controller can be set to provide both air¯ow requirements.

To set maximum and minimum cfm:

1.Set diffuser or wall thermostat for maximum cooling.

2.Turn the minimum cfm star wheel counterclockwise un- til the internal stop is reached. Do not attempt to override stop.

3.Shut off unit by adjusting thermostat to zero cool- ing, or disconnect tube from volume controller to thermostat.

4.Place a standard air¯ow hood against the outlet of the master unit and slowly turn the minimum cfm star wheel on the controller clockwise until the desired minimum cfm is reached.

5.Return the thermostat to the desired setting and/or recon- nect tube between volume controller and thermostat.

6.Adjust maximum cfm lever to desired percent cfm.

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