Inquiries have emerged regarding the necessary field wiring for RAUK No Controls and VAV options. The accompanying wiring diagrams will offer clarity on the components and their appropriate connections to the RAUK units. The content contained below is from a presentation that walks through the customer connection points for all configurations.
The presentation is also available for download at the bottom of the article.
No Control RAUK Custom Connection
All inputs to the 1XD33 termination block are 115Vac inputs. The unit wiring provides the 115Vac from the 1T1 transformer. The interlock is requred on all configurations, but the Freezestat is for EVP config only (Be sure to read the notes at the bottom of the schematic). If the unit is configured for "No Control" then the LLID devices for the Compressor staging inputs will not be present/installed in the unit's control box.
No Control Compressor Sequence
The 20 and 25 Ton units have 4 or 5 (The 25 Ton unit has two different size compressors and so Compressor 1A alone is ~60% capacity, the 20 Ton has the same size compressors).
The staging request for the 20 Ton is as follows:
- Cool 1 = 115Vac on 1XD33-10; Comp 1B Unloaded
- Cool 2 = 115Vac on 1XD33-10 & 15; 1B full load
- Cool 3 = 115Vac on 1XD33-10 & 9; 1A on 1B full load
- Cool 4 = 115Vac on 1XD33-9, 10, 15; 1A on 1B full load
This is just an example of recommended commands for the Compressor staging request to the 1XD33 terminals, but the sequence can be customized by the user per the note in the snip from the IOM.
So if a "Lead/Lag" is desired then staging can be altered, or if the controller does not have adequate outputs for all stages, then terminals may be "jumped" together. The Supply Air VAV and EVP configured units will use the sequence automatically to control to a "Discharge Air Temp Setpoint".
EVP and VAV Customer Connections
The inputs on the 1XD32 are all Vdc or "Normally Close to Common". The Froststat inputs are only required for "No Control" and VAV Configurations. EVP does not require the Froststatsince it will have a "FreezeStat" input. See pages 71 and 72 in "SS-SVX091C-EN" for the resistance values for the Discharge temp and Remote setpoint inputs.
The Emergency Stop, Equipment Stop, and Refrigerant monitor inputs must be closed to operate the unit even in Manual Override mode for all configurations.
Isolation Solenoid and Hot Gas Bypass Wiring
The Liquid Line Isolation Solenoid and Hot Gas Bypass valves are 115Vac outputs from then 1KF49 module to the 1XD33 terminal block. The Iso solenoids are required devides, but the HGBP are operational per the unit configuration and application.
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.