Refrigerant Sensor Integration into Climate Control Systems

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and benefit of U.S. provisional patent application No. 63/665,428 filed Jun. 28, 2024, which is herein incorporated by reference.

FIELD

This disclosure relates generally to climate control systems, such as heat pump systems and the like. In particular, embodiments of the disclosure are related to the integration of a refrigerant sensor (e.g., A2L sensor) into an older/legacy climate control system.

BACKGROUND

Conventional climate control systems, e.g., such as ones that use the non-DDC (Direct Digital Control) type control system, typically do not include a refrigerant leak sensor. Newer regulations in the industry now mandate the inclusion of a refrigerant leak sensor in climate control systems. It is often not easy to accommodate these new requirements into older systems. Accordingly, there is a need in the industry for techniques for accommodating these sensors in older/legacy systems.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is set forth with reference to the accompanying drawings. In some instances, the use of the same reference numerals may indicate similar or identical items. Various embodiments may utilize elements and/or components other than those illustrated in the drawings, and some elements and/or components may not be present in various embodiments. Throughout this disclosure, depending on the context, singular and plural terminology may be used interchangeably.

FIG. 1A illustrates a functional block diagram of a portion of a control board for a climate control system according to an embodiment of the present disclosure.

FIG. 1B depicts a table that illustrates operation details of the climate control system according to an embodiment of the present disclosure.

FIG. 2A illustrates a functional block diagram of a portion of a control board for a climate control system according to another embodiment of the present disclosure.

FIG. 2B depicts a table that illustrates operation details of the climate control system according to the other embodiment of the present disclosure.

FIG. 3 illustrates a functional block diagram of a portion of a control board for a climate control system according to yet another embodiment of the present disclosure.

FIG. 4 illustrates a functional block diagram of a portion of a control board for a climate control system according to a further embodiment of the present disclosure.

FIG. 5 illustrates a functional block diagram of a portion of a climate control system according to an embodiment of the present disclosure.

FIG. 6 illustrates a functional block diagram of a portion of a control board for a climate control system according to another embodiment of the present disclosure.

DETAILED DESCRIPTION

This disclosure relates generally to climate control systems, such as heat pump systems and the like. The techniques described in this disclosure are equally applicable to residential as well as commercial climate control systems. Similarly, the techniques described herein are applicable to a single compressor or a multi-compressor system. In particular, embodiments of the present disclosure are related to the integration of a refrigerant leak sensor into a climate control system that may not have this feature at the time of its manufacturing.

A “climate control system” may broadly encompass any system that is configured to heat and/or cool a conditioned space, heat and/or cool a fluid that is provided to a load, and/or perform any other actions associated with a vapor compression cycle. Non-limiting examples of types of climate control systems can include air conditioners (e.g., no reversing valve, only provides cooling mode), heat pumps (e.g., air source or geothermal; has a reversing valve and operates in both heating and cooling modes), heat pump water heaters, integrated heat pump water heaters, split system heat pump water heaters, heat pump water heaters with a circulation pump and a brazed plate heat exchanger, split systems, packaged systems, mini-splits, PTACs, window units, vertical packaged systems, VRF systems, etc.

For example, a climate control system may generally include components that combine to form a refrigerant loop that is used to produce conditioned air that is circulated throughout the conditioned space by the climate control system. For example, the refrigerant loop may include an indoor heat exchanger coil, an outdoor heat exchanger coil, a compressor, and an expansion valve (however, these components may vary, depending on the specific type of climate control system).

Continuing this example, during the operation of this exemplary climate control system in a cooling mode, warm indoor air is pulled (or pushed) over the indoor heat exchanger coil (which may be the evaporator coil of the climate control system) by a fan of the climate control system. As the liquid refrigerant inside the indoor heat exchanger coil converts to gas, heat is absorbed from the indoor air into the refrigerant, thus cooling the air that is pulled over the indoor heat exchanger coil. The fan is then operated to pull the cooled air into a conditioned space (such as a residential home or commercial establishment) that is being cooled by the air conditioning system. In some instances, this cooled air may be distributed throughout the conditioned space using ductwork installed within the conditioned space. The refrigerant gas then passes into the compressor. The compressor pressurizes the refrigerant gas and sends the refrigerant into the outdoor heat exchanger coil, which may operate as a condenser coil. A fan pulls outdoor air through the outdoor heat exchanger coil, allowing the air to absorb heating energy from the home and release it outside. During this process, the refrigerant is converted back to a liquid. The refrigerant then travels back to the indoor heat exchanger coil. The refrigerant passes through an expansion valve, which regulates the flow of refrigerant into the indoor heat exchanger coil. The cold refrigerant then absorbs more heat from the indoor air and the cycle repeats.

Likewise, in a standard heating mode, a reversing valve may be transitioned to direct refrigerant from the compressor to the indoor heat exchanger coil as opposed to directing it to the outdoor heat exchanger coil, as is done in the cooling mode. In a heating mode, the refrigerant absorbs heat from the outdoor air through the outdoor heat exchanger coil. The refrigerant then passes through the compressor, which compresses (and thus warms) the refrigerant. The heated refrigerant is transferred to the indoor heat exchanger coil. One or more fans push or pull air over the indoor heat exchanger coil, thereby transferring heat from the indoor heat exchanger coil to the conditioned space. Ductwork then directs the conditioned air throughout the conditioned space to heat the conditioned space. One or more supplemental heating sources, such as an electric heating kit, and/or a gas furnace with a heat exchanger in the indoor coil portion, may additionally be used. This description is merely exemplary and the specific operation of the climate control system may vary depending on the specific climate control system. FIG. 1A illustrates a functional block diagram of a portion of a control board 100 for a climate control system according to an embodiment of the present disclosure. It is to be noted that FIG. 1A only illustrates some of the components of the control board. One skilled in the art will realize that a control board for a climate control system will have many more components than the ones shown. Only the components that are useful to describe the embodiment are illustrated in FIG. 1A.

The control board 100 illustrated in FIG. 1A is for a climate control system that has two compressors. However, this is for illustration purposes only and the embodiment is not limited to use in a two compressor system as noted above. Control board 100 has two connection points 104 (L1) and 106 (L2). Connection point 104 is associated with a first compressor and is coupled to a comfort alert subsystem (not shown). Similarly, connection point 106 is coupled to another comfort alert subsystem. In some embodiments, both connection points 104 and 106 may be coupled to the same comfort alert subsystem. A comfort alert subsystem is designed to protect the compressor. The comfort alert subsystem monitors various vital parameters of the system, such as temperature, pressure, electrical, compressor faults, system faults, etc. If the comfort alert subsystem detects that any of the monitored parameters are out of the range of the acceptable values, the comfort alert subsystem then triggers an alert by sending a pulsed DC voltage signal on the line connected to input connections 104 or 106. In some embodiments, this voltage signal may be a 24V pulsed DC signal.

Once this pulsed DC signal is detected on either connection points 104 or 106, the system may turn off the appropriate compressor and/or take other mitigating actions to protect the compressor and associated circuit. During normal operation, a value of 0V may be detected at both of the connection points 104 and 106.

Many legacy climate control systems do not include a refrigerant leak sensor. Recent changes in the industry now mandate inclusion of a refrigerant leak sensor into the climate control system for added safety and reliability of the climate control system. However, it is not easy to incorporate a refrigerant leak sensor into such existing legacy systems due to the complexity of ensuring that the sensor and associated alerts work properly without any interference. In the embodiment illustrated in FIG. 1A, the input 106 (L2) is repurposed to also accept a signal from a refrigerant leak sensor 102 such that if sensor 102 detects a refrigerant leak, the system can take the appropriate mitigation actions. Sensor 102 can be any commercially available sensor (e.g., an A2L sensor) or may be a custom sensor. Sensor 102 is operable to output a signal if it detects refrigerant in its proximity.

During normal operation of the climate control system, there should not be any refrigerant present outside the sealed refrigerant circulation system. However, if there is a leak somewhere in the system, the refrigerant may generally seep into various areas of the climate control system, such as the air handler unit, control board area, and others. Sensor 102 can detect the presence of refrigerant in its proximity and output a signal indicating the presence of the refrigerant. Sensor 102 may be tuned to detect a single refrigerant or may be a broad-spectrum detector for many different types of refrigerants.

Connection points 104 and 106 are coupled to control logic 110. The function of control logic 110 is to receive inputs from connection points 104 and 106 and output the appropriate signals/instructions for switch 108 and blower control circuit 114. The details of the operation of control board 100 will be described below in connection with FIG. 1B. Switch 108 is coupled to connection point 106 (L2) and to the other comfort alert subsystem (not shown) and a voltage source 116.

Voltage source 116 may be a dedicated voltage source or may be shared with other components in the climate control system, e.g., a smoke detector. In an embodiment, voltage source 116 may output a continuous 24 VAC signal. Switch 108 is also coupled to sensor 102, which may control the operation of switch 108. Specifically, sensor may send a signal directly (or via another component) to switch 108 to operate switch 108 to either allow the pulsed DC voltage to appear at connection point 106 or the continuous 24 VAC to appear at connection point 106 by either connecting pole 1 with pole 3 or connecting pole 2 with pole 3. In an embodiment, switch 108 may be a double pole single throw (DPST) switch. In other embodiments, any other appropriate switch that can be controlled electronically may be used.

Control logic 110 is also coupled to blower control circuit 114. Control logic 110 can send an appropriate signal to blower control circuit 114 to control the operation of a blower (not shown) that is coupled to blower control circuit 114.

FIG. 1B illustrates the operation modes of the climate control system according to an embodiment of the present disclosure. Column 120 shows the various possible voltage signals that may be detected on connection point 106 (L2). Column 122 shows the various possible voltage signals that may be detected on connection point 104 (L1). Column 124 shows the associated operation mode descriptions.

During normal operation of the climate control system, control logic 110 may detect 0V on both connection points L1 and L2. Further, in normal operation, Pole 3 of switch 108 is electrically coupled to pole 1. Thus, during normal operation, connection point 106 (L2) is electrically coupled to the comfort alert system. The 0V input on connection point 106 (L2) indicated normal operation and no alarm related to the comfort alert system. In the event that the comfort alarm subsystem detects a fault, it will output a pulsed DC voltage and that pulsed DC voltage will be detected by control logic 110 at connection point 106 (L2). Control logic 110 may then take appropriate actions based on that determination.

In the instance where sensor 102 detects refrigerant in its proximity, sensor 102 sends a signal to switch 108. This causes the switch 108 to operate such that pole 2 is not electrically coupled to pole 3 and pole 1 is electrically severed from pole 3. This causes the continuous AC voltage from voltage source 116 to appear at connection point 106 (L2). Control logic 110 detects continuous AC voltage and sends the appropriate signals to disable/stop the compressors (not shown), and to start the blower (not shown) (for example, via the blower control circuit 114). This protects the climate control system from any damage due to refrigerant leaks, and also helps with evacuating any leaked refrigerant from the system by operating the blower. In this mode of operation, the voltage detected on the connection point 104 (L1) may be 0V, indicating that there is no issue with the comfort alert subsystem coupled to the respective compressor.

In another mode of operation, sensor 102 may indicate a refrigerant leak and input voltage on connection point 104 (L1) may be a pulsed DC voltage indicating that there is some issue with the compressor associated with L1. In this instance, similar to above, switch 108 is operated such that connection point 106 (L2) is coupled to the voltage source 116 and a continuous AC voltage is detected at connection point 106 (L2). In this instance, the system may indicate a refrigerant leak alert and a comfort alert. Based on this, control logic 110 may concurrently send the appropriate signals to shut down the compressor associated with connection point 104 (L1) and to turn on the blower associated with blower control circuit 114 to mitigate the refrigerant leak.

In yet another mode of operation, both connection points 104 and 106 may receive pulsed DC voltage input from their respective comfort alert subsystems. Control logic 110 may detect these voltages on L1 and L2, infer that both compressor systems are in a fault condition, and take appropriate actions to mitigate the problem/fault, e.g., shutting down both compressors and triggering a user readable alarm.

FIGS. 1A and 1B describe a hardware-based modification of the control board to accommodate the refrigerant sensor 102. In some embodiments, some changes to the software may also be needed to notify the appropriate user of the nature and type of alarm. In one embodiment, the user interface associated with the climate control system may be modified to show a specific alarm/fault condition associated with the refrigerant sensor 102. Such a fault condition may be outputted in a visual, audio, or audio-visual form via a user interface of the climate control system and in a manner that is readily discernible by a user or any other external control system that can act upon the information.

FIG. 2A illustrates a functional block diagram of a portion of control board 200 of a climate control system according to another embodiment of the present disclosure. In this embodiment, as in the embodiment of FIG. 1A connections points L1 and L2 are each associated with a respective compressor subsystem. In this embodiment, the connection point L2 is reconfigured to accommodate the inclusion of a refrigerant sensor 204. Both connection points L1 and L2 are powered by a phase monitoring circuit 202. Phase monitoring circuit 202 helps protect the climate control system from improper voltage or phasing. Phase monitoring circuit 202 may output a constant AC voltage. In an embodiment, the constant AC voltage may be 24 VAC, but it could be any other suitable voltage according to the system design and operation. Refrigerant sensor 204 is coupled to control logic 206.

Control logic 206 is coupled to switch 210. In an embodiment, switch 210 may be a double pole single throw (DPST) switch that can be controlled using a signal from control logic 206. One pole (3) of switch 210 is coupled to phase monitoring circuit 202. A second pole (1) of switch 201 is coupled to connection point L2 and the third pole (2) of switch 210 is coupled to a blower unit 208. Blower unit 208 may be realized using any known techniques in the art.

FIG. 2B illustrates operation modes of control board 200 according to an embodiment of the present disclosure. Column 220 illustrates the various voltage values that may be detected at the connection point L1. Column 222 illustrates the various voltage values that may be detected at the connection point L2. Column 224 illustrates the operational indication for the various combinations of voltages detected on connection points L1 and L2.

When the climate control system is running normally, the AC voltage, e.g., 24 VAC, from phase monitoring circuit 202 may be detected on both connection points L1 and L2. In this embodiment, pole 3 of switch 210 is electrically coupled to pole 1 of switch 210. In the instance that sensor 204 detects the presence of refrigerant in its proximity, it may send a signal to control logic 206. Control logic 206 may infer this signal to mean that there is some sort of refrigerant leak in the system and send a signal to switch 210. That signal causes switch 210 to disconnect pole 3 from pole 1 and instead electrically couple pole 3 to pole 2. This causes a loss of voltage at connection point L2 and the voltage at L2 may drop to about 0V. Further, now since pole 3 and pole 2 are electrically coupled, the AC voltage from phase monitoring circuit 202 is coupled to blower 208. This causes the blower to turn on and start evacuating any potential refrigerant that may have leaked.

In another operation mode of this embodiment, 0V may be detected at both L1 and L2. In this instance, it is likely that phase monitoring circuit 202 has detected some issue with the climate control system. The climate control system may then take appropriate measures to mitigate the issue detected by the phase monitoring circuit 202.

In this embodiment, one of the connection points (L2) for detecting phase monitoring related faults is reconfigured to also detect refrigerant leaks in the system. Thus, connection point L2 serves a dual purpose with only minor modification in existing control boards, and solves the problem of accommodating a new safety sensor in the system with minimal cost and complexity. As noted above, there may be some software modifications needed to notify the appropriate user or system of the refrigerant leak condition so that appropriate measures may be undertaken. Embodiments described above in connection with FIGS. 1A-2B can be implemented in control boards that are non-DDC (Direct Digital Control) type. Non-DDC control boards are normally used in legacy/older climate control systems.

FIG. 3 illustrates a DDC-type control board 300 of a climate control system according to an embodiment of the present disclosure. Specifically, FIG. 3 illustrates inclusion of a refrigerant detection system into a DDC-type control board according to an embodiment of the present disclosure.

Board 300 includes a remote terminal unit (RTU) 302. RTU 302 is a microprocessor-based electronic device used in industrial control systems (ICS) to connect various hardware to distributed control systems (DCS) or supervisory control and data acquisition (SCADA). RTU 302 includes a connection point 308 associated with a comfort alert subsystem (not shown). The operation of a comfort alert subsystem is described above and is not repeated again for the sake of brevity. Control board 300 also includes a line input 306 denoted by the letter ‘L’ in FIG. 3. Line input 306 provides a constant input voltage, e.g., 24 VAC. Control board 300 may also include a refrigerant detection system 304. Refrigerant detection system 304 may either be integrated into board 300 or may be external to board 300. In some embodiments, refrigerant detection system 304 may include a refrigerant sensor (e.g., A2L sensor) and associated control logic to receive and interpret the signals output by the refrigerant sensor. Refrigerant detection system 304 is electrically coupled to connection point 306 and connection point 308.

In normal operation, i.e., when no refrigerant leak is detected and there is not a conform alert triggered, the voltage on connection point 308 may be 0V. In the instance when the refrigerant detection system 304 detects a refrigerant leak, the refrigerant detection system 304 sends out a constant AC voltage, e.g., 24 VAC, over the line connected to connection point 308. This results in the constant AC voltage being read at connection point 308. The system interprets this signal to indicate that there is a potential refrigerant leak. In response, the system may turn on a blower (not shown) to disperse the refrigerant. In addition, the system may also trigger an audio, visual, or audio-visual alarm to notify the system operator of the fault condition associated with the refrigerant detection system 304. The embodiment of FIG. 3 can be implemented in a DDC-type control board.

FIG. 4 illustrates a portion of control board 400 according to yet another embodiment of the present disclosure. While the previous embodiment described a way to use the existing inputs on the control board to accommodate a refrigerant detection system, the embodiment of FIG. 4 illustrates the use of a dedicated input on the control board 400 to accommodate a refrigerant sensor.

Board 400 may include a RTU 408 and a refrigerant sensor 402. Refrigerant sensor 402 may be any of the similar sensors described above in relation to other embodiments. Sensor 402 is coupled to a refrigerant detection system 404. Refrigerant detection system 404 includes the necessary logic and processing units to receive input from sensor 402, interpret the input, and output a signal based on the input. Refrigerant detection system 404 is also coupled to power input 406 (R) on control board 400. If there is a refrigerant leak, sensor 402 may detect the leak and send the signal to refrigerant detection system 404, which in turn may send signal(s) to other components of the climate control system to cause appropriate actions to be taken to mitigate the leak. For example, refrigerant detection system 404 may send a signal to a blower unit to operate the blower to help evacuate/disperse the refrigerant to the external environment and also send a signal to the compressor(s) to stop the compressors and thereby prevent any further damage to the climate control system. Embodiment illustrated in FIG. 4 may be implemented in a DDC-type control board.

FIG. 5 illustrates a functional block diagram of a portion of a climate control system 500 according to another embodiment of the present disclosure. As is well-known in the art, MODBUS is a legacy client/server data communications protocol in the application layer. EcoNet® is a smart monitoring and control technology developed by Rheem Mfg. Co. located in Atlanta, GA, USA.

As illustrated in FIG. 5, system 500 includes a refrigerant sensor 502 is EcoNet enabled and may include both hardwired and wireless communication interfaces (not shown). Sensor 502 is capable of communicating with local control systems and/or external control systems over a wired or a wireless connection. Sensor 502 may support a custom communication protocol that may be incompatible with a legacy protocol, e.g., the MODBUS protocol. This embodiment describes how a sensor with a custom protocol can be integrated into a system that uses a legacy protocol.

System 500 also includes a custom protocol-to-legacy protocol translator 504. Translator 504 may be coupled to control logic 506 that supports the legacy protocol. Translator 504 includes a custom communication interface 508 is capable of communicating with sensor 502 either over a wired or wireless medium. Custom communication interface 508 is coupled to a central processing unit (CPU) 512. CPU 512 may include one or more processors. Custom communication interface 508 is also coupled to memory 514. CPU 512 is also coupled to memory 514. CPU 512 may include custom firmware that can received inputs from the customer communication interface 508 and output data in a format compatible with the legacy protocol and vice versa.

CPU 512 and memory 514 are also coupled to a legacy communication interface 510. The legacy communication interface 510 is coupled to the control logic 506. In an embodiment, control logic 506 may be the main control board of system 500.

In operation, the refrigerant sensor 502 may detect a refrigerant leak. It may communicate data related to the leak to the custom communication interface 508. Since the custom communication interface 508 is uniquely designed to communicate with sensor 502, it receives that data and sends that data to CPU 512. CPU 512 includes specialized firmware that can interpret the data, which is in the custom protocol format, and output data based on the received data. The data output by CPU 512 is in a format compatible with the legacy protocol. For example, based on determining that there is a refrigerant leak, the CPU may output data that instructs the associated compressor to shut down and/or data that instructs an associated blower to start operating to evacuate the leaked refrigerant.

CPU 512 sends the appropriate data to legacy communication interface 510 in a format compatible with the legacy protocol. Legacy communication interface 510 may then send the data to control logic 506, which implements the actions prescribed by the data, i.e., turn off the compressor, start the blower, etc. In this manner, a refrigerant sensor having a custom protocol that is different from a legacy protocol, such as MODBUS, can be integrated into a legacy climate control system to provide a new feature, e.g., refrigerant leak detection.

FIG. 6 illustrates a functional block diagram of a portion of a climate control system 600 according to another embodiment of the present disclosure. System 600 includes a voltage source 602. Voltage source 602 may be a stand-alone/dedicated voltage source or may be shared with another component of system 600, e.g., a smoke detector. Voltage source 602 outputs a constant AV voltage, e.g., 24 VAC. Voltage source 602 is coupled to two relays 604 and 606. Relay 604 is coupled to a high-pressure switch 608. High-pressure switch 608 can be realized using any know components in the art. Relay 606 is coupled to low-pressure switch 610. Low pressure switch 610 can be realized using any know components in the art. The function of a high-pressure switch and low-pressure switch is known in the art and is not repeated here for brevity.

Relay 604 is coupled to a refrigerant sensor 616. Relay 606 is also coupled to control logic 612. Control logic 612 is also coupled to the high-pressure switch 608 and low pressure switch 610. Control logic 612 can receive a signal from the two pressure switches, interpret the signal and output a signal to relay 606 to cause operation of the relay. Control logic 612 may also send one or more signals to other components of the system 600 in response to receiving the signals from high-pressure switch 608 and low-pressure switch 610. Relay 606 is coupled to a blower circuit 614, which can operate an associated blower unit (not shown).

In normal operation, i.e., when no refrigerant leak is detected, relay 604 is closed, thereby applying the voltage from voltage source 602 to both pressure switches 608 and 610. Relay 606 is open and hence no power is provided to the blower circuit 614. If the refrigerant sensor 616 detects a leak, it may send a signal to relay 604 either directly or via other circuit(s). This causes relay 604 to open, thereby tripping both pressure switches 608 and 610 concurrently. This concurrent tripping of pressure switches 608 and 610 is detected by control logic 612. Control logic 612 is programmed to interpret this concurrent tripping of pressure switches 608 and 610 as an indication that sensor 616 has detected a refrigerant leak. In response to receiving this signal(s) from pressure switches 608 and 610, control logic 612 sends a signal to relay 606 to close. As a result, voltage from voltage source 602 is provided to the blower circuit, which in turn activates the associated blower. The blower then operates to disperse/evacuate the leaked refrigerant from the system. In another embodiment, control logic 612 may also send another signal to the compressor circuit to shut down the compressor to prevent any further refrigerant leak and protect the compressor from damage. It is to be understood that concurrent tripping of high and low-pressure switches is unlikely to happen during normal operation and hence the above technique creates a unique operating situation that can be leveraged to accommodate a refrigerant leak sensor in a legacy system with minimal modifications.

In yet another embodiment, a stand-alone refrigerant sensor having three poles can be used. For example, an A2L refrigerant detection sensor made by Danfoss® may be used. This 3-pole sensor can be implemented in either a DDC-type or a non-DDC type control board. In a non-DDC type control board, the sensor can be coupled to the L2 input described above. In DDC-type control board, the sensor can be coupled to a dedicated input as described above in connection with FIG. 4. Such a sensor allows for independent control of a blower that results in the simplifying of the design, but may add more cost to the design.

The several embodiments described above provide for multiple ways of integrating a refrigerant leak sensor into legacy climate control systems as well as new-built climate control systems. As described in one of the embodiments above, a climate control system may include control logic and a voltage source coupled to a switch and configured to output a constant AC voltage. The switch is coupled to a first line input, a sensor is coupled to the switch, the first line input is coupled to the control logic, and a blower control circuit is coupled to the control logic. In one operation, the switch receives a signal from the sensor. The signal indicates the presence of a refrigerant in the vicinity of the sensor. In response to this, the switch operates to electrically couple the first line input to the voltage source. As a result, the control logic detects the constant AC voltage at the line input and causes the blower control circuit to operate a blower.

In another embodiment, a climate control system that uses the phase monitoring circuit to accommodate a refrigerant leak sensor is disclosed. Thea phase monitoring circuit that outputs a constant voltage. The system further includes a first line input that is coupled to the phase monitoring circuit. There is also a switch that is coupled to the phase monitoring circuit, a second line input, a blower unit, and control logic. The system also includes a sensor that is coupled to the control logic. In one operation and at a first time, the phase monitoring circuit is electrically coupled to the second line input via the switch and thus provides an AC voltage at the second line input. Thereafter at a second time, the sensor sends a signal to the control logic based on detecting a refrigerant leak and the control logic operates the switch to electrically disconnect the second line input from the phase monitoring circuit, thereby removing the AC voltage from the second line input. The second line input may then read 0V or some other very low voltage value.

In describing the disclosed technology, terminology is resorted to for the sake of clarity. It is intended that each term contemplates its broadest meaning as understood by those skilled in the art and includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.

Ranges may be expressed herein as from “about” or “approximately” or “substantially” one particular value and/or to “about” or “approximately” or substantially” another particular value. When such a range is expressed, the disclosed technology can include from the one particular value and/or to the other particular value. Further, ranges described as being between a first value and a second value are inclusive of the first and second values. Likewise, ranges described as being from a first value and to a second value are inclusive of the first and second values.

Herein, the use of terms such as “having,” “has,” “including,” or “includes” are open-ended and are intended to have the same meaning as terms such as “comprising” or “comprises” and not preclude the presence of other structure, material, or acts. Similarly, though the use of terms such as “can” or “may” are intended to be open-ended and to reflect that structure, material, or acts are not necessary, the failure to use such terms is not intended to reflect that structure, material, or acts are essential. To the extent that structure, material, or acts are presently considered to be essential, they are identified as such.

It is also to be understood that the mention of one or more method steps does not preclude the presence of additional method steps or intervening method steps between those steps expressly identified. Moreover, although the term “step” can be used herein to connote different aspects of methods employed, the term should not be interpreted as implying any particular order among or between various steps herein disclosed unless and except when the order of individual steps is explicitly required. Further, the disclosed technology does not necessarily require all steps included in the methods and processes described herein. That is, the disclosed technology includes methods that omit one or more steps expressly discussed with respect to the methods described herein.

It should be apparent that the foregoing relates only to certain embodiments of the present disclosure and that numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the disclosure.

Although specific embodiments of the disclosure have been described, numerous other modifications and alternative embodiments are within the scope of the disclosure. For example, any of the functionality described with respect to a particular device or component may be performed by another device or component. Further, while specific device characteristics have been described, embodiments of the disclosure may relate to numerous other device characteristics. Further, although embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the disclosure is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as illustrative forms of implementing the embodiments. Conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments could include, while other embodiments may not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments.