OPERATION

Power Up Mode — The unit will not operate until all the inputs, terminals and safety controls are checked for normal operation.

NOTE: The compressor will have a 5-minute anti-short cycle upon power up.

Units with Aquazone™ Complete C Control

STANDBY — Y and W terminals are not active in standby mode, however the O and G terminals may be active, depend- ing on the application. The compressor will be off.

COOLING — Y and O terminals are active in Cooling mode. After power up, the first call to the compressor will initiate a 5 to 80 second random start delay and a 5-minute anti-short cycle protection time delay. After both delays are complete, the compressor is energized.

NOTE: On all subsequent compressor calls the random start delay is omitted.

HEATING STAGE 1 — Terminal Y is active in heating stage 1. After power up, the first call to the compressor will initiate a 5 to 80 second random start delay and a 5-minute anti- short cycle protection time delay. After both delays are complete, the compressor is energized.

NOTE: On all subsequent compressor calls the random start delay is omitted.

HEATING STAGE 2 — To enter Stage 2 mode, terminal W is active (Y is already active). Also, the G terminal must be active or the W terminal is disregarded. The compressor relay will remain on and EH1 is immediately turned on. EH2 will turn on after 10 minutes of continual stage 2 demand.

NOTE: EH2 will not turn on (or if on, will turn off) if FP1 tem- perature is greater than 45 F and FP2 is greater than 110 F.

EMERGENCY HEAT — In emergency heat mode, terminal W is active while terminal Y is not. Terminal G must be active or the W terminal is disregarded. EH1 is immediately turned on. EH2 will turn on after 5 minutes of continual emergency heat demand.

Units with Aquazone Deluxe D Control

STANDBY/FAN ONLY — The compressor will be off. The Fan Enable, Fan Speed, and reversing valve (RV) relays will be on if inputs are present. If there is a Fan 1 demand, the Fan Enable will immediately turn on. If there is a Fan 2 demand, the Fan Enable and Fan Speed will immediately turn on.

NOTE: DIP switch 5 on S1 does not have an effect upon Fan 1 and Fan 2 outputs.

HEATING STAGE 1 — In Heating Stage 1 mode, the Fan Enable and Compressor relays are turned on immediately. Once the demand is removed, the relays are turned off and the control reverts to Standby mode. If there is a master/slave or dual compressor application, all compressor relays and related functions will operate per their associated DIP switch 2 setting on S1.

HEATING STAGE 2 — In Heating Stage 2 mode, the Fan Enable and Compressor relays remain on. The Fan Speed relay is turned on immediately and turned off immediately once the demand is removed. The control reverts to Heating Stage 1 mode. If there is a master/slave or dual compressor application, all compressor relays and related functions will operate per their associated DIP switch 2 setting on S1.

HEATING STAGE 3 — In Heating Stage 3 mode, the Fan Enable, Fan Speed and Compressor relays remain on. The EH1 output is turned on immediately. With continuing Heat Stage 3 demand, EH2 will turn on after 10 minutes. EH1 and EH2 are turned off immediately when the Heating Stage 3 demand is re- moved. The control reverts to Heating Stage 2 mode.

Output EH2 will be off if FP1 is greater than 45 F AND FP2 (when shorted) is greater than 110 F during Heating Stage 3 mode. This condition will have a 30-second recogni- tion time. Also, during Heating Stage 3 mode, EH1, EH2, Fan Enable, and Fan Speed will be ON if G input is not active.

EMERGENCY HEAT — In Emergency Heat mode, the Fan Enable and Fan Speed relays are turned on. The EH1 output is turned on immediately. With continuing Emergency Heat de- mand, EH2 will turn on after 5 minutes. Fan Enable and Fan Speed relays are turned off after a 60-second delay. The control reverts to Standby mode.

Output EH1, EH2, Fan Enable, and Fan Speed will be ON if the G input is not active during Emergency Heat mode.

COOLING STAGE 1 — In Cooling Stage 1 mode, the Fan Enable, compressor and RV relays are turned on immediately. If configured as stage 2 (DIP switch set to OFF) then the com- pressor and fan will not turn on until there is a stage 2 demand. The fan Enable and compressor relays are turned off immedi- ately when the Cooling Stage 1 demand is removed. The con- trol reverts to Standby mode. The RV relay remains on until there is a heating demand. If there is a master/slave or dual compressor application, all compressor relays and related func- tions will track with their associated DIP switch 2 on S1.

COOLING STAGE 2 — In Cooling Stage 2 mode, the Fan Enable, compressor and RV relays remain on. The Fan Speed relay is turned on immediately and turned immediately once the Cooling Stage 2 demand is removed. The control reverts to Cooling Stage 1 mode. If there is a master/slave or dual com- pressor application, all compressor relays and related functions will track with their associated DIP switch 2 on S1.

NIGHT LOW LIMIT (NLL) STAGED HEATING — In NLL staged Heating mode, the override (OVR) input becomes ac- tive and is recognized as a call for heating and the control will immediately go into a Heating Stage 1 mode. With an addition- al 30 minutes of NLL demand, the control will go into Heating Stage 2 mode. With another additional 30 minutes of NLL demand, the control will go into Heating Stage 3 mode.

SYSTEM TEST

System testing provides the ability to check the control operation. The control enters a 20-minute Test mode by mo- mentarily shorting the test pins. All time delays are increased 15 times. See Fig. 4.

Test Mode — To enter Test mode on C or D controls, cycle the power 3 times within 60 seconds. The LED (light-emitting diode) will flash a code representing the last fault when enter- ing the Test mode. The alarm relay will also power on and off during Test mode. See Tables 19 and 20. To exit Test mode, short the terminals for 3 seconds or cycle the power 3 times within 60 seconds.

NOTE: Deluxe D Control has a flashing code and alarm relay cycling code that will both have the same numerical label. For example, flashing code 1 will have an alarm relay cycling code 1. Code 1 indicates the control has not faulted since the last power off to power on sequence.

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Carrier 50RTG Operation, Units with Aquazone Complete C Control, Units with Aquazone Deluxe D Control, System Test
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50RTG specifications

The Carrier 50RTG represents a significant advancement in the field of rooftop air conditioning systems, combining performance, efficiency, and reliability for commercial applications. Designed to meet the rigorous demands of today’s buildings, the 50RTG series is ideally suited for a variety of environments, including retail, office spaces, and industrial facilities.

One of the standout features of the Carrier 50RTG is its energy efficiency. Utilizing the latest in compressor technology, these units achieve high Seasonal Energy Efficiency Ratios (SEER) and Energy Efficiency Ratios (EER), which translates to lower energy costs for users. This efficiency is further enhanced by the incorporation of environmentally friendly refrigerants that comply with current regulations, reducing the overall carbon footprint of the unit.

Another notable characteristic of the 50RTG series is its modular design. The unit can be tailored to specific requirements, making it versatile for different installation scenarios. This modularity not only simplifies maintenance and repair operations but also allows for easy upgrades as technologies evolve or as space demands change.

The advanced control system in the 50RTG is another key technology that sets it apart from competing products. Intuitive user interfaces and smart controls enable precise temperature regulation and improved energy management. These controls often include features such as variable speed fans and integrated economizers, which optimize the system's performance in real-time based on current load requirements.

Durability is also a hallmark of the Carrier 50RTG. Constructed with robust materials and designed to withstand harsh weather conditions, these units provide dependable operation year-round. The corrosion-resistant finish and weather-tight construction ensure that the systems maintain their performance levels and aesthetic appeal over time.

Additionally, the 50RTG series is designed with a focus on low noise operation. With quieter components and advanced noise control technology, these units are ideal for noise-sensitive environments, ensuring that occupants can work, live, or shop in comfort without disruptive background noise.

In summary, the Carrier 50RTG series exemplifies the perfect combination of energy efficiency, advanced technology, customization potential, durability, and low noise operation, making it a top choice for commercial heating and cooling needs. Its innovative features and reliable performance solidify its status as a leader in rooftop HVAC solutions, catering to the evolving requirements of modern buildings.
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