Problem:
What can the 24 volt deluxe controller do? How does it work?
Resolution:
The deluxe controls may be applied as a stand-alone control system. The stand-alone design provides accurate temperature control directly through a wall-mounted electronic thermostat.
This system set-up may be utilized in a replacement design where a single unit retrofit is needed. It may be easily interfaced with a field provided control system by way of the factory installed 18-pole terminal strip. This stand-alone control is frequently utilized on small jobs where a building controller may not be necessary, or where field installed direct digital controls are specified. This type of control design does require a constant flow of water to the water source heat pump.
With a positive way to sense flow to the unit, the units safety devices will trigger the unit off. The standalone system design provides a low cost option of installation while still allowing room control for each unit.
Deluxe controls include the following:
• 18-pole strip for low voltage field wiring
• For 0.5 to 5 tons, 50 VA transformer (75 VA for 6 to 25 tons)
• Anti-short cycle compressor protection
• Brown out protection
• Compressor contactor
• Compressor delay on start
• Compressor lock-out relay
• Condensate overflow
• Electric heat and compressor enable (6 to 25 tons)
• Freeze protection
• High pressure switch
• Hot gas reheat
• Low pressure switch
• Low pressure time delay
• Multi-speed fan motor
• Random start delay
• Reversing valve coil
• Soft lockout mode
Note: For .5 to 5 tons, hot gas reheat and electric heat units with deluxe controls offer a 75 VA transformer.
General Alarm Contact
Contact Configuration: Isolated dry SPDT
Operation: This contacts will be closed when the control goes into a manual lockout mode for either a high pressure, low pressure, or condensate overflow condition. Terminal designators are AL1 and AL2.
Compressor Disable (Load Shed)
Function: To temporarily suspend compressor operation if 24 VAC is present at terminals CD1 and CD2.
Operation: The source of this 24VAC signal would most likely be from the water loop controller in the system. It could be disabling the compressor because of low water flow or because of peak limiting. Once the compressor has been disabled the anti-short cycle time period will begin. The input (terminal “CD” will continue to be monitored and when the compressor disable signal (24 VAC) is no longer present, the control will allow the compressor to restart provided the anti-short cycle time has expired, safeties are satisfied and the run signal is still present. Note: This 24VAC is not from the same Class II transformer that is in the unit control panel, therefore separation of circuits requirements per UL will be necessary for the wiring of this signal into the unit
Generic Relay
Contact Configuration: Isolated SPDT pilot duty rated
Operation: This relay could be used for a variety of control features. Specifically it may be used for a night setback or pump restart function. An external Class II 24VAC signal will energize the relay coil on terminals “R1” and “R2”. Terminals “C” – common, “NO”- normally open, and “NC”- normally closed will be provided for the relay contacts.