13
RSM-DEV1 Technical Guide
SEQUENCE OF OPERATIONS
Staging
Stage Types
The RSM-DEV1 uses different staging sequences depending on the
unit configuration. Below are the different stage types the module
can use.
Please see
Table 6: Module Screens, Stage ID, page 24
.
• Stage Type 1 - Single VFD compressor
•
Stage Type 2 - VFD compressor plus on/off compressor
• Stage Type 3 - VFD compressor plus two-step
compressor
•
Stage Type 4 - VFD compressor plus tandem on/off
compressors
•
Stage Type 5 - Tandem VFD compressors with on/off
compressor plus tandem on/off compressors
•
Stage Type 6 - Four Circuit: VFD compressor, on/off
compressor, VFD compressor, and on/off compressor
Stage Type 1 - Single VFD
Units affected
• RQ 2-6 Ton
• RNA 7 Ton
• RNA 8 Ton
• RNA 10 Ton
• RNC 16 Ton
Modules
• Module 1(A): VFD
Stages for all modes
•
Stage 0: VFD is off
• Stage 1: VFD is on
Cooling, Heating, and regular Dehumidification Mode
Stage 0 to 1 (VFD stages on)
• No stage delay.
•
Minimum off time has been met.
• Controlling temperature is above the staging window for
cooling and below the staging window for heating.
• VFD turns on at recommended start speed (3,600 RPM
Copeland, 3,000 RPM Danfoss).
•
If Dehumidification Mode, VFD turns on immediately.
No conditions needed.
Stage 1 to 0 (VFD stages off)
• VFD was at minimum speed.
• VFD minimum run time met.
• Stage delay has been met.
• Controlling temperature is below the staging window for
cooling or above the staging window for heating.
•
If Dehumidification Mode, VFD is not allowed to stage
off.
Stage Type 2 - VFD Plus On/Off
Units affected
• RNC 30 Ton
Modules
• Module 1(A): VFD
•
Module 2(B): on/off
Stages for all modes
•
Stage 0: All are off
•
Stage 1: VFD is on; on/off is off
•
Stage 2: VFD is off; on/off is on
• Stage 3: All are on
Units with reheat on the second circuit have a different method of
staging for dehumidification.
Cooling, Heating, and regular Dehumidification Mode
Stage 0 to 1 (VFD stages on; on/off is off)
• No stage delay.
•
Minimum off time has been met.
• Controlling temperature is above the staging window for
cooling or below the staging window for heating.
• VFD turns on at recommended start speed (3,600 RPM
Copeland; 3,000 RPM Danfoss).
•
If Dehumidification Mode, VFD turns on immediately.
No conditions needed.
Stage 1 to 3 (VFD is on; On/Off stages on)
• VFD was at maximum speed.
• Stage delay has been met.
• Controlling temperature is above the staging window for
cooling or below the staging window for heating.
• VFD resets to recommended start speed (3,600 RPM
Copeland; 3,000 RPM Danfoss).
Stage 3 to 1 (VFD is on; on/offstages off)
• VFD was at minimum speed.
• Stage delay has been met.
• Controlling temperature is below the staging window for
cooling or above the staging window for heating.
• VFD resets to recommended start speed (3,600 RPM
Copeland; 3,000 RPM Danfoss).
Stage 1 to 0 (All stage off)
• VFD was at minimum speed.
• VFD minimum run time has been met.
• Stage delay has been met.
• Controlling temperature is below the staging window for
cooling or above the staging window for heating.
•
If Dehumidification Mode, VFD is not allowed to stage
off.
