Basic Operation - Non-Zoned; Pi Control; Load Value; Duty Cycles - American Standard AccuLink Platinum 1050 Installation Manual

6. Basic Operation – Non-Zoned
6.1

PI Control

The 1050 Control uses proprietary control schemes to
provide comfort and energy efficiency. The 1050 Control
senses indoor temperature and determines capacity
needed based on the following parameters:
• Mode of operation
• Proportional Error - distance from setpoint
• Integral Error - Time away from setpoint
72º
Set Point
2 Seconds
Temperature
B
B + C + D... = Integral Error
6.2

Load Value

The 1050 Control uses proportional plus integral error to
determine the amount of capacity required. The calculated
capacity is displayed as load value. Load Value is a numerical
representation of the needed capacity to maintain setpoint.
The load value range is dependent on the applied system.
LOAD VALUE RANGE - HEATING
0-100 Single Stage Heat Pump Only
0-200 Two Stage/VSPD Heat Pump Only
0-200 Single Stage Heat Pump + 1 Stage Electric/Wet Heat
0-300 Single Stage Heat Pump + 2 Stage Electric/Wet Heat
0-400 Single Stage Heat Pump + 3 Stage Electric/Wet Heat
0-300 Two Stage/VSPD Heat Pump + 1 Stage Electric/Wet Heat
0-400 Two Stage/VSPD Heat Pump + 2 Stage Electric/Wet Heat
0-500 Two Stage/VSPD Heat Pump + 3 Stage Electric/Wet Heat
0-100 Single Stage Indoor Heat Only
0-200 Two Stage Indoor Heat Only
0-300 Three Stage Indoor Heat Only
0-175 Single Stage Heat Pump + 1 Stage Gas/Oil Heat
0-275 Single Stage Heat Pump + 2 Stage Gas/Oil Heat
0-375 Single Stage Heat Pump + 2 Stage Gas/Oil Heat
0-275 Two Stage/VSPD Heat Pump + 1 Stage Gas/Oil Heat
0-375 Two Stage/VSPD Heat Pump + 2 Stage Gas/Oil Heat
0-475 Two Stage/VSPD Heat Pump + 3 Stage Gas/Oil Heat
11-HD15D1-5-EN
Integral Error
A
Room
Temperature
C D
A = Proportional Error
LOAD VALUE RANGE - COOLING
0-100 Single Stage Compressor
0-200 Two Stage/VSPD Compressor
A Load Value of 50 represents a request of 50% demand
for single stage cooling units ("Y") or 50% demand for stage
one of multistage cooling units ("Y1").
A Load Value of 150 represents a request of 100% demand
for stage one ("Y1") and 50% demand of stage two ("Y2")
for multistage cooling units.
6.3

Duty Cycles

Indoor temperature control is achieved by duty cycling
the equipment when the load value is less than 100% of
the current stage of operation. Duty cycles do not apply
to variable/modulating region of VSPD outdoor units or
modulating furnaces. The duty cycle rate is dependent on
the calculated load value.
The duty cycle chart below indicates the number of cycles
at 50% load (i.e. LV = 50).
6 CPH
2 CPH
As with all PI-based controls, the indoor temperature will
fluctuate above and below the user selected setpoint to
maintain comfort in the space. Adjusting the factory set CPH
(Cycles per Hour) can affect how tight the 1050 Control
operates around the setpoint. The CPH can be adjusted in
the Installer Setup>Equipment Settings (2 – 6 CPH)
• Factory default for compressor operation is 3 CPH
• Factory default for indoor heat is 5 CPH
Effects of changing the cycle rates
Lower CPH results in longer run cycles with less cycling
but the indoor temperature may deviate above and below
setpoint.
Higher CPH results in tighter indoor temperature control
but shorter, more frequent cycles.
6.4

Overshoot Clamp

The 1050 Control will enforce an "off cycle" anytime the
1050 Control overshoots more than 2.5°F. Once the indoor
temperature is within 0.75°F of setpoint an "on cycle" is
allowed dependent on load value and minimum off times.
Cooling Overshoot Clamping Example
Actual Temperature
75º
74.25º
72.5º
OFF Cycle Enforced ON Cycle Allowed
Platinum 1050
1 Hour
17