Patent Grant
9851112
Not Applicable.
Not applicable
Not Applicable
1. Field of the Invention
This invention relates to the field of heating, ventilation and air conditioning. More specifically, the invention comprises an electrical or electromechanical device that pulses the control line of an outdoor HVAC unit using the thermostat connections in order to indicate to a user which outdoor unit is associated with a particular indoor unit.
2. Description of Related Art
On most occasions heating, ventilation and air conditioning (HVAC) systems are set up with some components on the inside of a dwelling and some components on the outside. Such a system is often called a “split system.”
In the case of large apartment complexes, multiple outside HVAC units are often located behind the building or on the roof. The presence of multiple outdoor units can can make it difficult to determine which outside unit corresponds to a particular inside unit. This becomes an issue when air conditioning repair personnel need to access the outside unit, but are faced with a multitude of nearly identical units with no method for deducing which is the correct unit. This scenario is shown in
Control and refrigerant lines run from the inside units 12 in each apartment 24 to an associated outside unit 14. Due to the quantity of lines and the fact that portions of the lines may be concealed, it would be a complicated if not impossible task to follow the lines from the apartment to the correct outside unit. Therefore, another method is typically used. The current solution requires the repair technician to bring an additional helper along for the repair job. The helper is tasked with quickly switching the air conditioning unit on and off from the thermostat inside the apartment while the technician waits outside listening for which unit comes on. (The task of the technician and helper could easily be switched). In the case of an air conditioning unit with a heat pump, a typical method is to switch the unit from heating to cooling or vice-versa. This action actuates the reversing valve contained in the outside unit. The actuation of the reversing valve causes a loud click which may be easily head.
Those skilled in the art will know that the reversing valve in a heat pump outdoor unit directs the refrigerant to flow in a selected direction. In one direction the system is in cooling mode. In this mode the coils and fan inside the dwelling act as the evaporator and the outside coils act as the condenser, thus cooling the air inside the dwelling. When the valve is reversed to heating mode, the coils switch roles and the air inside the dwelling is heated.
Actuating the reversing valve, again located in the outside air conditioning unit, creates a distinct clicking sound which can be heard by a helper standing near the outside units. The helper may then identify which outdoor unit is associated with the thermostat that the other technician is manipulating. A cooling-only system does not have a reversing valve. In the case of a cooling-only unit, briefly switching the air conditioning unit on activates the start contactor for the compressor. This also generates a loud clicking sound. The outside helper is then able to correctly identify the outside unit by listening for this clicking sound. Developing a method to identity the correct outside unit without the need for a second technician on-site would reduce the cost of HVAC repair work in multi-unit situations. A device that does this automatically would allow only one technician to go out to a site, thus leaving the second technician available for another job and only paying one technician for a job that now only requires one person. It is also important that the device used to actuate the reversing valve be compatible with most air conditioning units. The proposed invention allows a single technician to identify the outside unit and is compatible with both heat pump and cooling-only systems.
The present invention comprises a simple electrical device that pulses a signal on a control line of an HVAC unit in order to allow the identification of an outside unit corresponding to a particular inside unit. The inventive device typically connects to the control lines at the thermostat. In the case of a heat pump system, the device pulses the control line connected to the reversing valve. This action briefly energizes the valve, thus switching it from heating to cooling mode, repeatedly. The device does not energize any other part of the system, it only switches the valve. The result of this pulsing of the reversing valve is a loud clicking noise. The repair technician leaves the device attached to the thermostat, and it continues to pulse. As the device pulses, this continuous clicking sound can be heard by the air conditioning repair technician when he or she walks outside to listen. The device hereby allows the technician to determine which outside unit is associated with the inside unit connected to the device inside the dwelling.
In the case of an HVAC system having only cooling capabilities, the inventive device pulses the control line of the start contactor for the compressor. This pulsing is quick enough so that the motor of the compressor is not engaged, but the start contactor does create a clicking sound, similar to the clicking heard from the reversing valve, when it is energized. The repair technician then listens outside for the clicking sound to determine the corresponding outside unit, as done with the heat pump unit.
The device connects to the existing wires contained in the thermostat of the air conditioning unit. This method allows the repair technician to connect the device to almost any air conditioning unit that he or she may encounter on the job. The device is preferably able to operate from the power contained in the thermostat or from power supplied by battery.
In addition to the previously stated attributes, the device comprises a circuit test function that tests for short circuits in the wires contained in the thermostat. The circuit has a breaker that trips with less current than the threshold of current of the breaker contained in the unit. By attaching the wires of the thermostat to wires of the circuit test (with the thermostat switched to off), the repair technician can determine whether there is a short in the circuit.
The present invention uses an electrical or electromechanical device, such as a time delayed relay driven by a fixed voltage, to pulse the control lines of an HVAC unit. The pulse generating device may be referred to as a “pulse generator.”
The preferred embodiment of the present invention is attached to the thermostat 22. It pulses the control lines 20. These lines lead to control circuit 18 contained within inside unit 12. Control lines 20 then run from inside dwelling 10 to outside unit 14, activating the correct mechanism as described in the succeeding text.
For the case of a heat pump HVAC system, the inventive device pulses the control line for the reversing valve.
This transportation is made possible by compressor 26, the heart of the cycle. It pressurizes the refrigerant, pumping it into the outside or inside coil (depending on whether the system is in heating or cooling mode). The pressurized refrigerant leaves the compressor 26 through the refrigerant line 16 connecting the compressor to reversing valve 28. As mentioned in the preceding text, reversing valve 28 allows one HVAC system to both heat and cool the dwelling rather than requiring two separate systems. Depending on what mode the system is in (heating or cooling), outside coil 30 receives refrigerant from reversing valve 28 or sends it. Outdoor fan 32 moves air over outside coil 30. Indoor fan 38 moves air over indoor coil 36.
Reversing valve 28 is commonly in an energized state during the cooling cycle (the energized state could just as easily be the heating cycle). In this state the pressurized refrigerant runs from compressor 26, through reversing valve 28, to outdoor coil 30 (which acts as a condenser), through expansion valve 34, and then to indoor coil 36. After passing through indoor coil 36 the gaseous refrigerant flows back through another portion of reversing valve 28 and then to the suction side of compressor 26.
Reversing valve 28 is in a de-energized state during the heating cycle. In that state the pressurized refrigerant runs from compressor 26, through the reversing valve to indoor coil 36. The indoor coil operates as a condenser. The refrigerant then flows from indoor coil 36 through expansion valve 34 and then to outdoor coil 30 (which acts as a evaporator).
The indoor fan 38 forces air across the indoor coil 36, which circulates the air through the dwelling to provide heating or cooling. The outdoor fan 32 forces ambient air over outdoor coil 30 to cool the outdoor coil (in air conditioning mode) or heat the outdoor coil (in heating mode).
In a heat pump unit, when the reversing valve line is energized, the valve creates a clicking sound. This sound is generated by the solenoid used to actuate the reversing valve. A solenoid is an electromagnetic device used to adjust the position of the reversing valve when necessary. The clicking sound created is the sound of the activation the solenoid that adjusts the valve. Briefly and repeatedly pulsing the control line thus creates a continuous clicking sound that is audible to a person nearby.
In the case of an air conditioning unit that is not a heat pump, the unit can only cool. This type of HVAC system does not contain a reversing so the outside coil always acts as a condenser and the inside coil always acts as an evaporator, as discussed in the preceding text. This situation does not allow the current invention to pulse the line for the reversing since there is not a reversing valve present. However, a large electromechanical start contactor is typically used to start the compressor.
A start contactor is a large electromechanical device that acts as a converter in an HVAC system. A 24 VAC signal is sent from the thermostat to the start contactor. Once the start contactor is energized with the 24 VAC signal, the contacts are closed and a 240 VAC circuit is completed. The 240 VAC signal is used to power the compressor. This device allows the use of a relatively low 24 VAC control signal to govern a 240 VAC power signal Similar to the reversing valve, the start contactor also creates a clicking sound when the control line for the compressor is activated. By rapidly and periodically pulsing the cooling line on a straight cooling unit, the start contactor generates a continuous clicking sound, thereby realizing the same effect as that observed using the reversing valve in the heat pump system. The start contactor is only energized for a brief interval—too short a time to actually start the compressor spinning.
A sequential block diagram showing the operation of an embodiment of the inventive device is shown in
The pulse generator 40, indicated in the block diagram, represents an embodiment that uses battery 42 to power time delayed relay 44 (or similar electrical circuit capable of creating a pulsed voltage). The electrical leads from the pulse generator 40 connect to the contacts for thermostat power 48 and reversing valve control 50 on thermostat 22. The pulsing device contained in pulse generator 40 periodically connects power to reversing valve control 50 (It applies a voltage to the reversing valve control line). When connected, the 24 VAC signal travels to control circuit 18 located within inside unit 12. That signal is then transmitted to solenoid 52 of reversing valve 28, which is located in outside unit 14. The rapid and periodic signal quickly energizes solenoid 52 and actuates reversing valve 28. With this actuation, a clicking sound is heard from outside unit 14, allowing the repair technician to locate the correct unit.
Another embodiment of the current invention allows for the device to be operated using power available on the thermostat itself rather than an external power source such as a battery. In this embodiment, the pulse generator has additional electrical lead wires connected to the pulsing circuit in order to provide power. The connection is preferably made using a temporary device such as such as alligator clips or the like (discussed further in the succeeding text).
Similar to the description in
There are many, many different ways to create a circuit that generates a suitable pulsed voltage. One approach is to use a simple electromechanical relay.
The preceding text regarding
As those familiar with the art will recall, a time-delayed relay can be set to cycle on and off. Connecting power to a relay switch, such as that found in
An example of a device that can control the timing aspect of the relay is a 555 timer. As those familiar with the art know, a 555 timer is an integrated circuit that comprises transistors, diodes and resistors. A 555 timer uses resistance and capacitance to bring a timing aspect to the circuit. The time constant of the RC circuit determines the pulse width coining from the timer. In order to adjust the timing and duration of the pulse, the resistance and capacitance of the resistors and capacitors in the system are changed.
A 555 timer has three modes, which include monostable, astable, and bistable. Monostable mode allows a single pulse to issue from the device, and bistable mode acts as a flip-flop circuit, which can be made to change states. The mode to be considered for the current purpose is the astable mode. This mode allows for continual pulsing, which is desired in this application. The frequency of the output (rectangular pulses) from the timer is determined by the resistance of the resistors and capacitance of the capacitor. Once these values are set, the device can pulse a relay switch (or many other devices) as desired in order to be used in the invention.
The following serves to give the reader a better understanding of the relationship between the settings contained in thermostat 22 in
Similarly,
The important addition is reversing valve contact 88, or the O contact. This is the contact the present invention connects to for a heat pump HVAC system. The reversing valve is energized when the system is in cooling mode. So when thermostat 22 in
There are numerous mechanisms that can be employed to attach the current invention to a thermostat.
In addition, a preferred embodiment of the invention comprises a method of testing for a short circuit within the thermostat. This circuit test function detects a short circuit in one of the thermostat control lines that run to the control circuit on the inside unit. It tests each line individually, which accounts for an air conditioning unit with a thermostat with any amount of control lines.
A typical unit has a breaker in the thermostat rated for 3-5 amps. Alternatively, the test function component of the current invention contains an internal breaker with a lower current rating. With the thermostat set to off, the device is attached to the thermostat contacts. Once the device is attached, the tripping of the breaker indicates that there is a short circuit.
The combination of a pulsing circuit for the application described previously and short circuit test operation is convenient for a repair technician. Both functions are implemented on the thermostat and connect electrically. Thus, it is convenient and cost-effective to use a device that is already connected to the thermostat to inspect the system for short circuits.
A specific description of the device has been established. Many other embodiments and applications are possible. For example, although heat-pump and AC-only systems have been discussed, the engine could also be applied to a heat-only refrigerant circulation system. The function, method of operation and preferred embodiment has been set forth, but the invention should be understood in the broad sense, as stated by the following claims rather than by any particular example given.
| Number | Name | Date | Kind |
|---|---|---|---|
| 6089310 | Toth | Jul 2000 | A |
| 7222800 | Wruck | May 2007 | B2 |
| 7821218 | Butler | Oct 2010 | B2 |
| 20090266092 | Harrod | Oct 2009 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20170241651 A1 | Aug 2017 | US |
