Symbio 700 in the Odyssey condenser requires a set of closed contacts from the AHU leak detection connected to UC P21-1 & 2 (TB-T1, TB-T2) for the condenser to operate.
Note: If the AHU has a Trane controller factory installed (UC400/600/Symbio 500), do not use the wiring below. See notes below for more information
Leak detection sensors in UCCA air handlers are connected to the 1W1 board. The sensor is powered by the 1W1 and when normal (no alarm) and powered, switches the neutral/ground on the 1W1 to TB7-17 (EX FS+). Since the sensor is switching a ground, a relay must be added to the AHU that is controlled by this switched ground.
See drawings below for connection to the 1W1 and from the relay to the condenser:
1W1 Board
Connection Between 1W1 and Symbio 700
For more information about the 1W1 board and it's operation see this link:
UCCA with 1W1 Customer Interface Board + Field Leak Detection Sensor Integration
Trane Controllers: If the AHU has a factory installed Trane controller, there may be wiring from 1W1 J11-2 (XM30 plug) to a Universal Input (UI) point on a XM30 or on the controller. With the wiring to the 1W1 board above, the relay is controlled by switching the ground/neutral to the relay coil so when the A2L sensor is tripped, it is dropping the neutral/ground to the relay coil. If a relay is used as shown above with the wire from J11-2 connected to a UI on the controller or XM30 AND the A2L sensor is tripped, the connection to the UI on the controller can provide enough of a ground/neutral to hold the relay and not shut the condenser down. Also, this can cause the UI to not be reliable and 24vac is being sent to the UI when the LDS is tripped/active.
With a Trane controller, the relay should be wired to the controller and controlled by logic in that controller and not wired to the 1W1.
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.