American Standard CH530 manual Reset Ratio, Outdoor air temperature versus degrees of reset

Machine Protection

and Adaptive

Control

Reset Ratio:

The Reset Ratio is displayed as a percentage. To use it in the above equation it must be converted to it’s decimal form.

Reset Ratio percent /100 = Reset Ratio decimal

Example of converting Reset Ratio:

If the Reset Ratio displayed on the CLD is 50 percent then use (50/100)=

.5 in the equation

TOD = Outdoor Air Temperature

Start Reset = Outdoor Air Start Reset

Example of Calculating Reset for Outdoor Air Temperature:

If:

Reset Ratio = 35 percent

Start Reset = 80

TOD = 65

Maximum Reset = 10.5

How many Degrees of Reset will there be?

Degrees of Reset = Reset Ratio*(Start

Reset - TOD)

Degrees of Reset = .35*(80-65)

Degrees of Reset = 5.25

If:

Reset Ratio = -70 percent

Start Reset = 90

TOD = 100

Maximum Reset = 17

How many Degrees of Reset will there be?

Degrees of Reset = Reset Ratio* (Start

Reset - TOD)

Degrees of Reset = -7* (90-100)

Degrees of Reset = 7

(* = multiply)

Figure 32. Outdoor air temperature versus degrees of reset

CDHF-SVU01C-EN 85