Large Unitary Technical Support has received several calls regarding replacement LCI modules obtained by field technicians. In some cases, the technicians were unaware that the new LCI-X module requires both a new wire harness and a different 24 VAC power source. Before beginning the replacement, review the unit’s Controls Options Module schematic to verify the correct wiring configuration, harness requirements, and power source for the specific unit. Following the schematic will help ensure proper installation and prevent compatibility or operational issues.
LCI-I Wiring - typical on units that shipped before 2013
The 24 VAC supply is routed from the 1TB7 terminal block and connected to the J2 terminals on the LCI-I. The LCI-I receives this 24 VAC power from one of the ungrounded 24 VAC transformers, which serves as the source for the control voltage.
LCI-X Wiring - units built after 2013, field kits and replacement for LCI-I
The 24 VAC supply is provided from the 1TB10 terminal block and is routed to the J1 terminals on the LCI-X. The LCI-X receives its 24 VAC power from a grounded 24 VAC transformer, which supplies the required low-voltage power for the device.
Missing Harness
Replacement LCI-I modules have not been available for IntelliPak units since 2013. When replacing an original LCI-I module, the preferred solution is to specify the complete replacement kit. The kit includes the required wiring harnesses, the LCI-IX board, and all necessary mounting hardware to support a proper installation.
For IPAK I units, specify kit KIT16474. For IPAK II units, specify kit KIT16475.
If the complete replacement kit is unavailable, or if only a replacement LCI-X module was ordered, technicians may fabricate the required harness in the field using the components listed below. The harness should be assembled carefully to ensure that all terminals are properly installed and that the connector is wired correctly for the application.
Use connector CON00378, which is a four-pin connector. Also use KIT02866, which contains ten wires per kit. Each wire is six inches long and includes a terminal that inserts into the connector plug.
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.