Defrost System: Description and Troubleshooting

Overview

Heat wave and AeroTemp Icebreaker models incorporate an active, time and temperature, hot-gas defrost system. Basically stated, when an evaporator coil thermostat senses a significant icing condition, the control circuit reverses the flow of refrigerant, sending hot refrigerant vapor to the outdoor coil. The effect is a rapid melting of ice and frost, and a quick return to the normal heating mode.

Major Components

♦Defrost Controller: Monitors condition (open or closed) of binary outdoor coil defrost temperature sensor (DTS). The controller accumulates compressor run time where conditions are conducive to ice formation. Upon an accumulation of a predetermined period of “ice forming” run time, controller initiates a defrost cycle by supplying control voltage through the DTS, energizing the coil of control relay #1 (CR-1); in turn, CR-1 energizes the refrigerant circuit reversing valve (and stops fan operation), sending hot refrigerant vapor to the outdoor coil. (When the DTS warms, the DTS contacts open, de- energizing the refrigerant reversing valve and–if a call for heat is present–re-starting the fan motor.)

♦Defrost Temperature Sensor (DTS): Normally-open SPST switch that attaches to a return loop of the evaporator (outdoor) refrigerant coil. The DTS senses evaporator coil temperature, and sensor contacts close on a fall in temperature. Specifications: Close @ 25°F, Open @ 55°F (+- 9°F).

♦Control Relay #1 (CR-1): 3-pole, double-throw relay, equipped with a 24-volt control coil. Upon an accumulation of sufficient “icing run time” this relay receives a 24-volt signal from the defrost controller, through the DTS. When CR-1’s coil is energized, the refrigerant reversing valve is energized; the fan relay is de-energized; the defrost light is illuminated, and the defrost controller reset circuit (RST) is opened.

♦Fan Relay: DPDT relay, used in a SPST capacity; relay is equipped with a 24-volt control coil. During normal heating (non-defrost) operation, the control coil is energized and electrical power for the fan motor is provided through the closed terminals of this relay. Upon a call for defrost, CR-1 interrupts control voltage to the fan relay. With Fan relay “open”, fan operation ceases.

♦Refrigerant Reversing Valve (RRV): Mechanical, 24-volt, pilot operated electric solenoid valve. During heating mode, the RRV control coil is de-energized. Upon a call for defrost, the RRV control coil is energized through CR-1. Now energized, the RRV diverts hot refrigerant vapor to the outdoor refrigerant air coil, and defrost is accomplished.

Sequence of Operation

1.Start... Normal Heating Cycle in Operation: evaporator temperature above 25°F;

2.Evaporator temperature falls to 25°F; DTS closes, and the defrost controller begins accumulating “ice forming” run time. Run time accumulates only when the compressor is operating.

3.With DTS remaining closed, and when sufficient “ice forming” run time has accumulated (50-Minutes for Heat Wave and AeroTemp models), the defrost controller initiates a defrost cycle.

4.The heater will remain in defrost until the DTS opens; except, if, after 10-minutes, the DTS has not opened, the defrost controller will terminate the defrost cycle.

5.If defrost was terminated by the defrost controller, with DTS still closed, the defrost controller will immediately begin accumulating “ice forming” run time. Otherwise, “ice forming” run time will not begin accumulating until such a time that the DTS re-closes.

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Aquacal H/AT120R Defrost System Description and Troubleshooting, Overview, Major Components, Sequence of Operation
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H/AT120R, H/AT100R specifications

Aquacal H/AT100R and H/AT120R are leading heat pump models designed to efficiently heat swimming pools while promoting energy savings and environmental sustainability. These units are renowned for their advanced technology and impressive performance, making them a popular choice among pool owners.

One of the standout features of the Aquacal H/AT series is its high-efficiency operation. Both models are equipped with a high-performance compressor and heat exchanger that work together to maximize heat transfer. This efficiency translates into lower energy consumption, which not only reduces utility bills but also minimizes the carbon footprint associated with pool heating.

The H/AT100R and H/AT120R utilize advanced refrigeration technology, integrating state-of-the-art components that enhance their overall reliability and durability. The titanium heat exchanger is particularly noteworthy as it provides exceptional resistance to corrosion, ensuring longevity in various water conditions. This means pool owners can enjoy their heated pools for years without worrying about the negative effects of chemical treatment or saltwater.

Another significant technological innovation in these models is the incorporation of a user-friendly digital control panel. This intuitive interface allows users to easily monitor and adjust the temperature settings, facilitating a customized swimming experience. Moreover, the H/AT series is equipped with a built-in timer, enabling automatic operation to ensure the pool is heated precisely when needed.

Aesthetically, the Aquacal H/AT100R and H/AT120R have been designed with a sleek, compact form factor that allows for easy installation in residential and commercial settings. Their quiet operation is another feature that enhances user experience, offering a tranquil swimming environment without the disruptive noise often associated with conventional heating systems.

In terms of environmental friendliness, both models are designed to utilize eco-friendly refrigerants, aligning with modern regulations and promoting sustainable pool heating solutions. This commitment to sustainability reflects Aquacal's proactive approach to meeting the needs of environmentally-conscious consumers.

In conclusion, the Aquacal H/AT100R and H/AT120R heat pumps are notable for their advanced technology, high energy efficiency, user-friendly operation, and environmentally responsible design. These features come together to provide pool owners with a reliable, effective, and sustainable solution for pool heating, ensuring that they can enjoy their aquatic space year-round without compromising on energy efficiency or environmental impact.
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