34
Operation
Unit operations should be controlled with
the controller, never at the main power
supply, except for servicing, emergency or
complete shutdown of the unit.
Cooling
Single or Two Stage
Stage 1 - Variable Capacity Scroll
Compressor
Stage 2 - Single Stage Compressor
RN/RQ - Unit Size = 3-25 or 30 tons
RN/RQ - Refrigerant Style = E, F
RN/RQ - Unit Configuration = A, B, J, K, 6,
7
RN/RQ - Model Option A4 - Cooling/Heat
Pump Staging = 9, A
Heating
0, 1, 2 or 3 Stages or Modulating/SCR Gas
or Electric Heat
RN/RQ - Model Option B1 - Heating Type
= 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
RN/RQ - Model Option B3 - Heating Stages
= 0, 1, 2, 3, 9
Return Air/Outside Air Section
Manual Outside Air Opening, Motorized
Outside Air Damper, Economizer and CO
2
Override
RN/RQ - Feature 1A - Return/Outside Air
Section = 0, A, B, C, F, G, H, J, L, N, P, Q,
R, S, T, U, V, W, Y, Z, 1, 2, 3, 5
RN/RQ - Feature 2 - Outside Air Control =
0, C, D, E, P, R
Refrigeration Options
Standard or Modulating Hot Gas Reheat
RN/RQ - Feature 8 - Refrigeration Controls
= 0, A, B, C, D, E, F, G, H, J, K, L, M, N
Controls
Constant Volume, Constant Volume Heat
Pump, Single Zone VAV - VAV Cool + CV
Heat, Single Zone VAV - VAV Cool +
VAV Heat, or Single Zone VAV Heat Pump
- VAV Cool + VAV Heat
RN/RQ - Feature 13 - Special Controls = E,
Y, Z, 2, 3
RN/RQ - Feature 22 - Control Vendors = E
Constant Volume Cooling Operation - Space
Temperature Control
When the space temperature has deviated ½
of the space temperature deadband above the
cooling space temperature setpoint the
variable capacity scroll compressor is
activated at 100% for one minute. The
compressor then modulates to maintain the
cooling space temperature setpoint.
For heat pump units with the controller
configured for the reversing valve to be
activated during the cooling mode of
operation, all reversing valves are activated
along with the variable capacity scroll
compressor.
For units with two stage cooling, if the
variable capacity scroll compressor operates
at a maximum capacity for a compressor
stage delay amount of time and the space
temperature is increasing the second
compressor is activated and the variable
capacity scroll compressor modulates to
maintain the cooling space temperature
setpoint.
For units with two stage cooling, if the
variable capacity scroll compressor operates
at a minimum capacity for the compressor
stage delay amount of time and the space
temperature is decreasing the second
compressor is de-activated. The variable
capacity scroll compressor then modulates
to maintain the cooling space temperature
setpoint.
As the space temperature achieves the
cooling space temperature setpoint minus ½
of the space temperature deadband the
