Carrier 50KQL-1PD manual Features/Benefits cont

Features/Benefits (cont)

Anti-short cycle timer — Provides a minimum off time to prevent the unit from short cycling. The 5-minute timer energizes when the compressor is deenergized, resulting in a 5-minute delay before the unit can be restarted.

Random start relay — Ensures a random delay in energizing each differ- ent WSHP unit. This option minimizes peak electrical demand during start-up from different operating modes or after building power outages.

High and low pressure refrigerant protection — Safeguards against unreliable unit operation and prevents refrigerant from leaking.

Condensate overflow sensor — Electronic sensor mounted to the drain pan. When condensate pan liquid reaches an unacceptable level, the unit is automatically deactivated and placed in a lockout condition. The sensor recognizes thirty continuous seconds of overflow as a fault condition.

High and low voltage protection — Safety protection for excessive or low voltage conditions.

Automatic intelligent reset — Unit shall automatically restart 5 minutes after shutdown if the fault has cleared. Should a fault occur 3 times sequen- tially, lockout will occur.

Accessory output — In applications such as variable speed pumping, a

24-v output cycles a motorized water valve or damper actuator with compressor.

Performance Monitor (PM) — Unique feature monitors water temper- atures to warn when the heat pump is operating inefficiently or beyond typical operating range. A field select- able switch initiates a warning code on the unit display.

Water coil freeze protection (selectable for water or anti- freeze) — Field selectable switch for water and water/glycol solution sys- tems initiates a fault when tempera- tures exceed the selected limit for 30 continuous seconds.

Air coil freeze protection (check filter operation) — Field selectable switch for assessing excessive filter pressure drop initiates a fault when temperatures exceed the selected limit for 30 continuous seconds.

Alarm relay setting — Selectable

24-v or pilot duty dry contact provides remote alarm activation.

Electric heat option — Output pro- vided on the controller for operating two stages of emergency electric heat.

Service test mode with diagnostic LED (light-emitting diode) — Test mode allows service personnel to check the operation of the WSHP and control system efficiently. Upon enter- ing Test mode, time delays speed up, and the Status LED flashes a code indicating the last fault. This mode provides easy fault diagnosis; based on the fault code the status LED flashes, Carrier provided troubleshooting tables provide easy reference to typical problems.

LED visual output — An LED panel indicates high pressure, low pressure, low voltage, high voltage, air/water freeze protection, condensate over- flow, and control status.

Carrier PremierLink™ control- ler adds reliability, efficiency, and simplification

The PremierLink direct digital control- ler can be ordered as a factory-installed option. Designed and manufactured

exclusively by Carrier, the controller can be used to actively monitor and control all modes of operation as well as monitor the following diagnostics and features: unit number, zone tem- perature, zone set point, zone humidity set point, discharge air temperatures, fan status, stages of heating, cooling stages, outdoor-air temperature, leaving-air temperature, leaving water temperature, alarm status, and alarm lockout condition.

This controller has 38.4K baud communications capability and is com- patible with ComfortLink™ Controls, CCN and ComfortVIEW™ Software. The Scrolling Marquee and Navigator are optional tools used for program- ming and monitoring the unit for opti- mal performance. Adding the Carrier CO2 sensor in the conditioned space provides ASHRAE 62-99 compliance and Demand Control Ventilation (DCV). A DCV control strategy is espe- cially beneficial for a water source heat pump system to minimize the energy used to condition ventilation air. In combination with energy efficient Aquazone units, DCV may be the most energy efficient approach ever devel- oped for a water source heat pump system.

The PremierLink peer-to-peer, Internet ready communicating control is designed specifically for Constant Volume and Variable Volume Tempera- ture applications. This comprehensive controls system allows water source heat pumps to be linked together, cre- ating a fully functional HVAC (heating, ventilation, and air conditioning) auto- mation system.

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