Systems and Methods for Determining Water Pump Status Using Current Consumption

This application claims priority to and benefit of U.S. provisional patent application No. 63/567,565 filed Mar. 20, 2024, which is herein incorporated by reference.

The present disclosure relates generally to heating, ventilation, and air conditioning (HVAC) systems and more particularly to systems and methods for determining water pump status using current consumption.

Some HVAC systems may include water pumps that are used to pump water produced within the HVAC system for improved heat transfer. For example, the water pumps may pump condensate produced by an indoor coil within an indoor portion of the HVAC system to an outdoor coil. The water pumps may also pump water produced during a defrost of the outdoor coil from an outdoor portion of the HVAC system to the indoor coil. However, these water pumps may, at certain points in time, ineffectively pump water or may fail to pump any water at all due to various factors, such as blockages. This may result in excess water accumulation within the HVAC system, which may potentially result in damage to components within the HVAC system.

The detailed description is set forth with reference to the accompanying drawings. The drawings are provided for purposes of illustration only and merely depict example embodiments of the disclosure. The drawings are provided to facilitate understanding of the disclosure and shall not be deemed to limit the breadth, scope, or applicability of the disclosure. The use of the same reference numerals indicates similar but not necessarily the same or identical components; different reference numerals may be used to identify similar components as well. Various embodiments may utilize elements or components other than those illustrated in the drawings, and some elements and/or components may not be present in various embodiments. The use of singular terminology to describe a component or element may, depending on the context, encompass a plural number of such components or elements and vice versa.

This disclosure relates to, among other things, systems and methods for determining water pump status using current consumption. In some HVAC systems, one or more water pumps may be provided to transfer water produced, or collected, within indoor and/or outdoor portions of the HVAC system. For example, condensate may be produced by an indoor coil during a cooling operation of the HVAC system, which may lead to water buildup within the indoor portion. A water pump may be provided within the HVAC system that pumps the water from the indoor portion to an outdoor coil located in the outdoor portion. Likewise, water buildup may occur within the outdoor portion as part of a defrost operation during a heating mode during which frost buildup on the outdoor coil is melted. Another water pump may be used to transfer this water buildup from the outdoor portion to the indoor coil. The water pumps may therefore serve the dual purpose of removing water buildup from a portion of the HVAC system and repurposing such water to improve heat transfer of the coils within the HVAC system. Reference is made herein to window units (an example of which is illustrated in), however, this is not intended to be limiting, and the systems and methods described herein may also be applicable to other types of HVAC systems, heat pumps, heat pump water heaters, and/or other types of systems that use water pumps to transfer water to one portion of the system to another portion of the system.

Within such systems, it may be desirable for the HVAC system to automatically monitor the status of the one or more water pumps to determine if the one or more water pumps are properly pumping the water from the indoor portion to the outdoor coil and/or from the outdoor portion to the indoor coil. For example, in some instances, one of the water pumps (or both of the water pumps) may be pumping a mixture of air and water or may not be pumping any water at all. If the water pump is not properly operating, water buildup may occur within the indoor portion or the outdoor portion, which has the potential to damage or otherwise impact the operation of the components of the HVAC system.

To monitor the status of the one or more water pumps, the system and methods described herein may, periodically or in real-time, measure the current consumption of the one or more water pumps. The current consumption of a water pump may provide an indication as to the amount of water that the water pump is currently pumping. In some embodiments, the system may store pre-determined ranges of current values and may compare the measured current consumption of the water pump with the pre-determined ranges to determine the amount of water that the water pump is pumping. For example, when a discharge side is not blocked, and a water pump is pumping only air, the current consumption may be within a range of 20 to 30 mA. When the water pump is pumping approximately 50% water and 50% air, the water pump may consume 40 to 60 mA. When the water pump is pumping only water, the water pump may consume 80 to 90 mA. On the discharge side, when the water pump outlet of the water pump is blocked, the current consumption may rise to over 180 mA.

These ranges of current values are not intended to be limiting but are provided merely to illustrate exemplary ranges of values and any other ranges and number of ranges may also be used. These ranges may depend on the specific type of water pump, the configuration of the HVAC system, and/or any other number of factors. Additionally, in some instances, single current value thresholds may be used rather than ranges of values. For example, the system may determine that the water pump is pumping only air if the current consumption falls below 30 mA, rather than determining if the current consumption falls within a range of 20 mA to 30 mA.

In some embodiments, data from other sensors may also be used in combination with the current consumption data. For example, one or more sensors may be provided in the indoor and/or outdoor portions of the HVAC system. The one or more sensors may capture data that is indicative of water levels within the indoor portion and/or the outdoor portion. For example, one or more float switches may be provided at the base pans of the indoor portion and/or outdoor portion. The one or more float switches may be provided at various heights within the indoor portion and/or the outdoor portion and may provide an indication of when the water level reaches these particular heights. This water level data may also provide information about the operation of the water pumps. For example, if a water pump is instructed to pump water from an indoor portion but the water level remains the same or continues to rise, then this may be an indication that the water pump is not properly functioning. The use of the sensors may also serve as a redundancy for the current consumption data. While reference is made to the use of float switches, any other types of sensors may also be used as well, such as optical sensors, etc. (additional examples of types of sensors are described below).

Based on the current consumption data, the data obtained from the sensors, and/or any other types of data, the HVAC system may automatically take various appropriate actions. For example, if it is determined that a water pump is not operating properly, the HVAC system may automatically cease operation to prevent further water buildup, which may otherwise result in damage to components of the HVAC system and/or other undesirable impacts, such as leaks into indoor spaces. As another example, the HVAC system may produce an error code or other type of alert to indicate to a user that the water pump is not properly operating. The error code (or other types of alert) may be displayed via a user interface of the HVAC system and/or may be presented to a user device (for example, a smartphone, etc.) or other type of device (as a further non-limiting example, the device may be a thermostat). The error code may provide an indication to the user to check, clean, and/or replace components of the HVAC system, such as the water filter, water pump(s), pressure relief valve, the water lines, etc. The error code (or other types of alert) may also be provided (e.g., auditory, visual, etc.) in any other form and to any other type of system or device.

These systems and methods described herein improve the efficiency of the HVAC systems by only using the water pumps when necessary to transfer water, which may minimize power consumption and may extend the operable life of the water pumps or other system components. The systems and methods also provide for the most efficient water pump operation by detecting if the pump is pumping only air, a mix of air and water, or only water using the current consumed by the pump. While some conventional systems may use sensors and timing intervals to monitor the operation the water pumps, the use of these sensors and timing intervals alone may still result in inefficient operation of the water pumps.

Turning to the figures which illustrate non-limiting examples of the disclosed systems and methods,illustrate an HVAC system. Particularly,depicts a first perspective view of a first side of the HVAC systemanddepicts a second perspective view of a second side of the HVAC system. The HVAC systemmay include an indoor portion, an outdoor portion, and a bridgeconnecting the indoor portionand the outdoor portion. The HVAC systemshown inmay specifically a system that is provided within a window of an environment to be heated and/or cooled, such as a residential home or a commercial building, for instance. For example, the bridgemay rest on a window sill, the indoor portionmay be located within an indoor environment (such as the residential home or commercial building, for example), and the outdoor portionmay be located within an outdoor environment. However, the systems and methods described herein may also be applicable to other types of HVAC system. Some of the components included within the indoor portionand the outdoor portionare described below; however, this is not intended to be a comprehensive description of all potential components that may be found within the HVAC system.

In some embodiments, the indoor portionmay include an indoor coil, a network transceiver, a user interface, a water purifier, an outdoor water filter, one or more water pumps (e.g., a first water pumpand a second water pump), one or more sensors (such as sensorand sensor), and a controller. Other components may also be provided in the indoor portion.

The indoor coiland the outdoor coilfunction as heat exchangers. In a cooling mode of the HVAC system(for example, when the HVAC systemis used to cool the environment in which the indoor portionis provided), the indoor coilof the HVAC systemmay serve as an evaporator coil. The indoor coilmay hold refrigerant and remove both heat and humidity from the air in the indoor environment (for example, the environment in which the indoor portionis located). The outdoor coilmay serve as a condensing coil. After the indoor coilcondenses humidity from the inside air, the heat is stored in the refrigerant located in the indoor coil. This refrigerant is transferred to the outdoor coil. When the outdoor coilreceives the refrigerant, the heat is released into the external environment (for example, the outdoor environment in which the outdoor portionis provided).

The network transceivermay be used to transmit and/or receive data to any systems, devices, etc. located remotely from the HVAC system. For example, the network transceivermay perform wireless or wired communications with a user device (for example, user device, etc.), another HVAC system, a remote server (for example, remote server, etc.), etc. For example, if an alert may be transmitted to a user device (or other type of device) when the controllerdetermines that a water pump is not properly functioning.

The controller(which may be the same as controlleror any other controller described herein or otherwise) may perform any of the operations described herein with respect to the HVAC system(or any other HVAC system), such as measuring the current consumption of a water pump, comparing the current consumption to one or more ranges of current values, causing an alert to be transmitting, causing operations of the HVAC systemto cease or be otherwise modified. Further details about the controllerare provided with respect to controllerof.

A schematic of a circuitused to measure the current of a water pump (for example, first water pumpand second water pump) is shown in. The circuitincludes a water pump (for example, the figure shows first water pump, however, any other water pump may be applicable) that is powered by a power source. In this specific example, the power source is a 24V DC power source, however, any other power source may be used. The circuit also includes a current sense amplifier, which is a differential amplifier that provides an output voltage proportional to the current flowing into a shunt resistorconnected to its input. This output voltage is used by the controllerto determine the current consumption of the water pump. This circuitis not intended to be limiting and the current may be measured in any other manner as well.

The user interfacemay present information to a user. For example, the user interfacemay present an alert when it is determined that a water pump is not properly functioning as described herein, other status information pertaining to the HVAC system, as well as any other types of information. The user interfacemay also be configured to receive inputs from a user, such as a temperature setting and/or any other control instructions that may be provided by the user. For example, the user interfacemay be a touchscreen display, but may also be provided in any other suitable form as well (for example, the user interfacemay include physical buttons that a user may process to provide inputs to the HVAC system). The user interfacemay be in communication with the controllerto provide information about inputs received from a user to the controller, display information received from the controller, etc.

The one or more water pumps (for example, first water pumpand second water pump) may be used to transfer water produced within the indoor portionand/or outdoor portionof the HVAC system. For example, during a cooling mode of the HVAC system, condensate produced by the indoor coilmay accumulate in an indoor drain panof the indoor portion(the indoor drain panis also shown inas indoor drain pan). In a defrost operation during a heating mode of the HVAC system, the outdoor coilmay be defrosted to remove frost that forms on the outdoor coiland the defrost water (melted) from the outdoor coilmay accumulate in an outdoor drain pan(the outdoor drain panis also shown inas outdoor drain pan). Water buildup may also occur within the indoor portionand/or the outdoor portionfor other reasons.

This accumulated water may be transferred from one portion of the HVAC systemto another portion of the HVAC systemto provide for improved heat transfer within the HVAC system. The improved heat transfer may result from evaporating the water onto the outdoor coiland/or indoor coil. Improved heat transfer may also be accomplished by pumping the water to a sump loop. In some instances, the first water pumpmay be dedicated to pumping water from the indoor portionto the outdoor coiland the second water pumpmay be dedicated to pumping water from the outdoor portionto the indoor coil. Particularly, the water pumped from the indoor portionmay be the condensate produced by the indoor coilwithin the indoor portionand the water pumped from the outdoor portionmay be the melted defrost water from the outdoor coil. However, other configurations, including any other number of water pumps, are possible.

Additional data about the amount of water accumulation may also be obtained from the one or more sensors (such as sensorand sensor). For example, the first sensorand the second sensormay be float switches that are provided at, or in, the base pans of the indoor portionand/or outdoor portion. The first sensorand the second sensormay be provided at various heights within the indoor portionand/or the outdoor portionand may provide an indication of when the water level reaches these particular heights. Further details about the sensors are provided with respect to at least.

The water filtermay be used to filter the water to be substantially free of particulates or other materials such that the water pump(s) are protected. The water purifiermay be used to purify the water to remove any contaminants. For example, the water purifiermay be an ultraviolet (UV)-C light emitting diode (LED) or any other type of purifier. In scenarios where microbial films form on stagnant water, the water purifier, water pumps, and water filtermay be used to reduce or eliminate microorganisms and prevent clogging of the water transfer elements of the HVAC system.

In some embodiments, the outdoor portionmay include an outdoor coil, an outdoor motor, and an outdoor fan(which may include a slinger ring), a high pressure switch, a low pressure switch, a reversing valve, a compressor, and an electronic expansion valve (EEV).

The outdoor motormay drive the outdoor fan. The outdoor fanis used to facilitate heat exchange between surrounding air and refrigerant flowing through the outdoor coil. That is, as refrigerant flows through the outdoor coil, the outdoor motordrives the outdoor fan, which blows air over the outdoor coilto exchange heat (e.g., heat or cool) with the external environment. The outdoor fanmay also include a slinger ring. When the outdoor motordrives the outdoor fanand the outdoor fanbegins rotating, the outdoor fanmay come into contact with water that is accumulated within a base pan of the outdoor portionof the HVAC system. As the outdoor fanrotates, the slinger ringmay cause the accumulated water to be thrown from the base pan and against the outdoor coil. The flow of refrigerant may be controlled by the reversing valveand the EEV.

The high pressure switchmonitors pressure on a discharge side of the compressor. If the pressure surpasses a first threshold pressure value, the high pressure switchopens to prevent the compressorfrom being powered. The low pressure switchprovides the opposite functionality of the high pressure switchand opens to prevent the compressorfrom being powered if the pressure falls below a second threshold pressure value. If the pressure is too low, then there may be insufficient lubricant return to protect the components of the compressor.

are block diagrams illustrating the operation of the one or more water pumps to transfer water from the indoor portionto the outdoor coiland/or from the outdoor portionto the indoor coil. The block diagrams represent top-down views of the HVAC systemof.

Beginning with, a block diagramis shown illustrating a cooling mode of the HVAC systemof. Indoor water(for example, in the form of condensate) is produced by the indoor coilas a byproduct of the operation of the HVAC system. The indoor waterthat is collected within the indoor portion(for example, in the indoor base pan) is pumped to the outdoor coilby the first water pump. The indoor watermay be pumped to the outdoor coilthrough a first water lineand/or a second water line, as well as any other number of water lines. In some instances, the number of water lines that are used (or the specific water lines that are used) may depend on the back pressure within the system. The water lines may be made from any suitable material, such as insulated plastic tubes, metal tubes, etc. In some embodiments, the indoor wateris pumped to fine spray nozzlesthat expel the cool water onto the outdoor coilto cool the outdoor coiland provide for more effective heat transfer. Any water that does not evaporate after being expelled onto the outdoor coilmay be slung back onto the outdoor coilvia the slinger ringof the fan. A pressure relief valve may open if the back pressure increases beyond a threshold value to send water to a drip channel.

Turning to, a block diagramis shown illustrating a defrost operation during a heating mode of the HVAC systemof. In the defrost operation, frost that has formed on the outdoor coilmay be melted into water to prevent frost accumulation within the HVAC system. Gravity may cause the defrost waterto flow to a low point in a base pan of the outdoor portion(for example, the outdoor base pan). The defrost watermay then be pumped from the outdoor portion, through a second water line, and into the indoor portionusing the second water pump. The defrost watermay also be pumped to the indoor portionthrough any other number of water lines.

In some embodiments, a coarse filterprovided at the outdoor portionmay be used to catch larger debris and prevent such debris from being transported through the water lines (which may cause blockage in the water lines). Additionally, a fine filtermay be provided at the indoor portion, which may be used to protect components within the indoor portion, such as the second water pump, the purifier, etc. The water received at the indoor portionmay then be pumped back to the outdoor portionusing the first water pump. Compressor heat and insulated tubing may be used to prevent water from freezing and to ensure that warm water is expelled from the fine spray nozzlesonto the outdoor coilin this defrost operation.

illustrates a perspective view of an indoor drain panof the HVAC systemof. Particularly,shows indoor water(which may be condensate) traveling across the indoor drain pantowards one or more indoor water drains. That is, the indoor drain panmay be angled such that indoor waterflows away from the electronics provided in the HVAC system, to a low point in the indoor drain panwhere the one or more indoor water drainsare located. This is also depicted in the side view of the indoor drain panin.

illustrates a perspective view of an indoor drain panof the HVAC systemof. Particularly,shows a close-up view of one or more sensors (for example, sensorand sensor) that may be used by the HVAC systemto determine a water level within the indoor drain pan.shows a first sensor, which may be a first float switch. The first sensormay be provided at a greater height from the indoor drain panthan a second sensor. When the first sensorindicates that the water in the indoor drain panis at the height associated with the first sensor, the HVAC system may signal for the compressor to turn off (to prevent any further generation of water). Additionally, an alert and/or instructions may be presented via the user interfaceof the HVAC systemand/or may be transmitted to any other device. For example, the alert and/or instructions may be generated by the controller(or any other controller described herein or otherwise).

When the second sensorindicates that the water in the indoor drain panis at the height associated with the second sensor, the HVAC systemmay signal the indoor condensate pump to turn on and pump water onto the top of the outdoor coil. If the float switch does not drop (e.g., open) or the current consumption of the water pump is low, an alert and/or instructions may be presented via the user interfaceof the HVAC systemand/or may be transmitted to any other device.

also illustrates that the indoor drain panmay include spill-over notches. These spill-over notchesmay be located slightly above the height of the first sensorto prevent water from entering an area of the HVAC systemthat includes electrical control components, to prevent damage to such components.

In some embodiments, the first sensormay be provided 3/16″ below the height of the spill-over notchesto reduce the likelihood that the water builds up to the height of the spill-over notchesand serves as another layer of protection against water overflow and damage to electronic components. In embodiments, the second sensormay be provided at a height that is 3/16″ to ¼″ lower than the first sensor. However, these sensors may be provided at any other height. Additionally, any other number of sensors may be used. Finally, while reference is made to the use of float switches, any other types of sensors may also be used (further examples are described with respect to).

illustrate operation of the water pumps of the HVAC systemof. Beginning with, operation of the first water pumpthat is used to pump water from the indoor portionof the HVAC systemto the outdoor coilis shown. Particularly, indoor wateris shown as flowing across the indoor drain pan. The indoor wateris pumped by the first water pumpthrough a water linetowards the outdoor spray nozzles. A pressure relief valvemay also be provided that may be used to divert some or all of the indoor waterdirectly to a top of the outdoor coilif the pressure surpasses a threshold value.

Turning to, operation of the second water pumpthat is used to pump defrost waterfrom the indoor portionof the HVAC systemto the indoor coilis shown. A fine filtermay be provided at the indoor portion, which may be used to protect components within the indoor portion, such as the second water pump, the purifier, etc. The defrost wateris pumped from the outdoor portion, through water lines, and into the indoor portion. Filtered and purified defrost watermay reside in the indoor drain panuntil the first water pumpturns on and pumps the defrost waterinto the outdoor portionto be sprayed onto the outdoor coil.

illustrates another example HVAC system. Particularly,illustrates another type of window unit that does not include the bridgeshown in the HVAC systemof. Similar to the HVAC system, the HVAC systemincludes an indoor portionincluding an indoor coiland an outdoor portionincluding an outdoor coil. However, the HVAC systemuses only a single water pump.

Water that is produced, or collected, within the indoor portionand/or the outdoor portionmay naturally transition to a low point within the HVAC systemby operation of gravity (for example, into a base panof the HVAC system, which may be the same as, for example, indoor base pan). The single water pumpand filtermay be used to transfer the cool water onto the top of the hot outdoor coilin the cooling mode and transfer warm water onto the top of the frosted outdoor coilduring the defrost operation in the heating mode.

illustrates a flow diagram. The flow diagrampresents logic that may be used by the controller (for example, controller, controller, etc.) of the HVAC system to monitor the status of water pumps within the HVAC system (and perform operations based on the determined information). Some or all of this logic may also be implemented on any other device or system (such as a remote server, a thermostat, a user device, etc.).

The flow diagrambegins with operation, which involves measuring the current consumption of a water pump. For example, the controller may be in electrical communication with the water pump. As the water pump draws current from an energy source (such as a utility energy source to which the HVAC system is connected, a battery, etc.), the current draw may be determined by the controller (for example, using the circuitshown in).

Once the current consumption of the water pump is determined, the determined current value may be compared to various pre-determined ranges or values of current values. That is, a particular type of water pump may normally exhibit current consumption values that fall within specific ranges of current values depending on the operation of the water pump. For example, the water pump may typically consume a first amount of current when the water pump is pumping at or close to 100% water, a second amount of current when the water pump is experiencing a blockage and is not pumping any water or is pumping less than a threshold amount of water, a third amount of current when the water pump is pumping a mixture of air and water (e.g., 50% air, 50% water), and a fourth amount of current when the water pump is pumping at or close to 100% air. These pre-determined ranges of current values may vary depending on the specific type or model of water pump.

Additionally, while the flow diagramillustrates a specific number of current value ranges including specific current values, these ranges and specific values included within the ranges are not intended to be limiting and are merely presented for illustrative purposes. For example, in some instances, only two or three (or any other number) ranges of current values may be used.

At condition, the measured current value may be compared to a first range of current values. In the particular example shown in, the first range of current values may include current values ranging from 80 mA to 90 mA. In some water pumps, a current consumption value falling within this range may indicate that the water pump is pumping at or close to 100% water and is functioning as intended. If conditionis met, then the operation of the water pump continues, and the flow diagramloops back to operationto periodically (or in real-time) perform further current consumption measurements.

However, if conditionis not met, then the flow diagrammay continue to conditionand the measured current value may be compared to a second range of current values. In the particular example shown in, the second range of current values may include current values ranging from 40 mA to 60 mA. In some water pumps, a current consumption value falling within this range may indicate that the water pump is pumping less than 100% water (that is, the water pump is pumping both water and air). In this case, the water pump may continue to function, however, a notification may be provided to a user at operationto provide an indication that the water pump may not be functioning entirely as intended. This notification may be presented via a display of the HVAC system (for example, HVAC systemand/or any other HVAC system), a user device (for example, user deviceand/or any other user device), etc.

If conditionis also not met, then the flow diagrammay continue to conditionand the measured current value may be compared to a third range of current values. In the particular example shown in, the third range of current values may include current values ranging from 20 mA to 30 mA. In some water pumps, a current consumption value falling within this range may indicate that the water pump is pumping substantially only air and no water, which may indicate that the water pump is not functioning as intended. For example, if water is present within the HVAC system that is intended to be pumped by the water pump and the current consumption value falls within this third range, then the water pump may not be functioning properly since it is not pumping any water. In this case, the flow diagram may proceed to operationin which an alert is issued and/or operation of the water pump and/or the operation of the water pump(s) and/or the HVAC system as a whole may be ceased. This alert may be presented via a display of the HVAC system (for example, HVAC systemand/or any other HVAC system), a user device (for example, user deviceand/or any other user device), etc. In some instances, data from the float switches (or other types of sensors described herein) may also be used to verify whether water is present in the HVAC system.

If conditionis also not met, then the flow diagrammay continue to conditionand the measured current value may be compared to a third range of current values. In the particular example shown in, the fourth range of current values may include current values that are above 180 mA. In some water pumps, a current consumption value falling within this range may indicate that the water pump is experiencing a blockage and not functioning properly. In this case, the flow diagram may also proceed to operationin which an alert is issued and/or operation of the water pump and/or the HVAC system as a whole is ceased. This alert may be presented via a display of the HVAC system (for example, HVAC systemand/or any other HVAC system), a user device (for example, user deviceand/or any other user device), etc.

While the flow diagramonly illustrates that the current consumption of a water pump is compared to ranges of current values to determine actions to take with respect to the HVAC system, the controller may also consider other factors, such as a rate of change of the current consumption of a water pump. For example, a water pump may currently only be consuming 60 mA of current; however, the current consumption may be increasing at such a rate that the current consumption may rise above 180 mA within a given period of time. Thus, in some instances, even if the current consumption does not currently fall within a particular range of current values, the controller may predict that the current may eventually reach the range of current values based on the rate of change of the current. In this manner, the controller may cause an action to be taken that is otherwise normally associated with the current consumption being within a particular range of current values even if the current consumption is not currently within that particular range.

Further, the operations shown in flow diagramare merely intended to illustrate examples of actions that may be taken based on the comparison of a current measurement of a water pump to one or more ranges of current values. These specific actions are not intended to be limiting and any other actions may also be taken. As one example, a notification may not necessarily be provided if the current measurement falls within the second range of values.

are flow diagrams for water pump operation. Beginning with, a flow diagramis shown including control logic for a water pump (for example, water pump, water pump, or any other water pump described herein). The control logic may be implemented on a controller, such as controlleror controller, for example.

The flow diagrambegins with condition, which involves determining if there is a demand for operation of a water pump (for example, if the controller determines that the water pump should be used to pump water from an indoor portion of the HVAC system to the outdoor coil or from the outdoor portion of the HVAC system to the indoor coil). If conditionis met, then the flow diagramproceeds to operationand the pump is activated to begin pumping water. Operationinvolves determining the amount of current that is being consumed by the water pump (for example, in accordance with the logic shown in).