2-Stage Compressor Information
Some Odyssey dual circuit condensers have utilized 2-stage compressors in the past, but the product line up has expanded to utilize 2-stage compressors on more equipment. All units that utilize a 2-Stage compressor in some fashion will require both Y1 & Y2 thermostat inputs to utilize both compressor stages. Dual circuit units will operate both compressors with a Y1 call in first stage and then full capacity with Y1+Y2.
Dual Circuit Condensers with 2-Stage Compressors
Odyssey 10 and 20 ton dual circuit units that utilized Electromechanical, ReliaTel controls and Symbio 700 controls built through 2022 were the only dual circuit models that utilized 2-Stage Compressors, staging is shown in the chart below. ReliaTel condenser production was ended in Fall 2020.
Unit models:
- TTA1204*D
- TTA2404*D
In 2023, units were updated to meet 2023 DOE requirements and added 7.5T TTA, 12.5T TTA, 7.5T TWA & 10T TWA. Electromechanical and ReliaTel control condensers were discontinued.
Unit models:
- TTA0904*D
- TTA1204*D
- TTA1504*D
- TTA2404*D
- TWA0904*D
- TWA1204*D
In 2025, all Odyssey condensers were changed to R454B refrigerant, no new tonnages were added.
- TTA090K*D
- TTA120K*D
- TTA150K*D
- TTA240K*D
- TWA090K*D
- TWA120K*D
Cooling Staging for these models below:
| Compressor 1 | Compressor 1 Unloader Solenoid | Compressor 2 | Compressor 2 Unloader Solenoid | |
| Y1 (Cool1)* (a) | ON in 1st Stage | OFF in 1st Stage | ON in 1st Stage | OFF in 1st Stage |
| Y2 (Cool1)* (a) | ON in 1st Stage | OFF in 1st Stage | ON in 1st Stage | OFF in 1st Stage |
| Y1+Y2 (Cool2)** (a) | ON in 2nd Stage | ON in 2nd Stage | ON in 2nd Stage | ON in 2nd Stage |
*Unit operates at ~66-67% capacity
**Unit operates at 100% capacity
(a) TWA units require 24vac on W1/O (UC J21-3) on thermostat controlled units to operate in cooling. Mechanical Heat for a Heat Pump is 100% capacity.
Single Circuit Condensers with 2-Stage Compressors
2020 Single Circuit Odyssey Condenser with Symbio 700 Controls
- TTA0904*C
2023 Single Circuit Odyssey Condenser with Symbio 700 Controls
- TTA0904*A
- TWA0904*A
- TWA1204*A
2025, all Odyssey condensers were changed to R454B refrigerant, no new tonnages were added.
- TTA090K*A
- TWA090K*A
- TWA120K*A
Cooling Staging for these models below:
| Compressor 1 | Compressor 1 Unloader Solenoid | |
| Y1 (Cool1)* (a) | ON in 1st Stage | OFF in 1st Stage |
| Y2 (Cool1)* (a) | ON in 1st Stage | OFF in 1st Stage |
| Y1+Y2 (Cool2)** (a) | ON in 2nd Stage | ON in 2nd Stage |
*Unit operates at ~66-67% capacity
**Unit operates at 100% capacity
(a) TWA units require 24vac on W1/O (UC J21-3) on thermostat controlled units to operate in cooling. Mechanical Heat for a Heat Pump is 100% capacity.
Note: For Symbio 700 controlled units, the ability for these units to operate the 2-Stage compressors is based on the Symbio 700 firmware and the EFFICIENCY setting in the Symbio 700 configuration.
- Symbio 700 controlled units built prior to 2023 (serial numbers starting with 20 thru 22) should always be set to EFFICIENCY = STANDARD.
- If a 7.5/12.5T TTA or 10/12.5T TWA built before 2023 has the firmware updated and gets EFFICIENCY set to STANDARD B, it will run the unit at 100% capacity as the software thinks there are 2-Stage compressors when there are actually not.
- All Symbio 700 controlled units built after 2023 (serial numbers starting with 23 and up) should be set to EFFICIENCY = STANARD B.
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.