Abstract:
Thermostatic Controller and Circuit Tester is a new trouble shooting device, designed to improve the air conditioning technicians fault diagnostic capabilities. The device comes equipped with two independent circuits and its own built in flashlight. The first circuit is the controller, which is outfitted with test leads with alligator clips controlled by four push on-push off switches. When attached to the thermostat wires or the air handlers connector block, it allows the air conditioning system to be manually overridden, so as to determine and locate defects in the system. The next circuit, with detachable test leads and probes, performs line voltage and continuity tests.

Description:
BACKGROUND OF THE INVENTION 
   Field of the Invention 
   The present device is designed for use and deployment in the “HEATING VENTILATING AND AIR CONDITIONING” (HVAC) industry and relates to a thermostatic controller and circuit tester, and more particularly, to a portable thermostatic controller and circuit tester. This utility device along with its attributes, is the product of years of working and tolerating the shortcomings of current test equipment available to the trade. 
   Package units located on roofs or on the sides of buildings, air handlers and water cooled heat pumps located in dark closets and sometimes attics, sometimes pose a challenge to the technician, mainly because of their accessibility by ladders only. 
   This sometimes requires the technician to ascend and descend ladders to test the repairs made, by operating the thermostat, or he can shout down to someone (if available) to operate the thermostat. 
   SUMMARY OF THE INVENTION 
   A portable thermostatic controller and circuit tester is provided for the trades needs and demands as envisaged by the inventor, of whom, is a HVAC technician. This device is time saving and space saving, while giving the technician greater flexibility and latitude when working alone. 
   In one embodiment of the present invention, the thermostatic controller and circuit tester device comprises two separate circuits that performs independently of each other. The two circuits are never integrated, except when using the circuit tester to check continuity of the controller circuit, whenever necessary. In another embodiment of the present invention, the portable thermostatic controller device comprises at least a controller circuit and a built in flashlight. 
   The thermostatic controller and circuit tester, in accordance with the present invention, is ideal for fieldwork, in the workshop and classroom demonstration. But nowhere does its attributes comes into its own, than in fieldwork. That is when its usefulness is highlighted due to its diverse working environment. 
   With a thermostatic controller and circuit tester, in accordance with the present invention, all a technician needs to do is switch the thermostat to off and switch off the line voltage disconnect switch located on or nearby the unit, to off. Using the device of the present invention, the technician can then proceed to troubleshoot and make repairs. When repairs have been completed, a thermostatic controller and circuit tester, in accordance with the present invention, via a set of alligator clips, is then attached to the low voltage connector block or thermostat wire connections by removing the twist-on wire connectors and exposing the bare wires. The controller circuit can then be operated by pressing switches located on the face thereof. 
   With the portable device of the present invention, the technician avoids unnecessary trips to the thermostat location, saves time and energy and most of all he is now very independent of extra tools and helping hands. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an isometric view of a portable thermostatic controller and circuit tester in accordance with one particular embodiment of the present invention. 
       FIG. 2  is a schematic circuit diagram of a controller circuit of the thermostatic controller and circuit tester, in accordance with one embodiment of the present invention. 
       FIG. 3  is a schematic circuit diagram of a test circuit of the thermostatic controller and circuit tester, in accordance with one embodiment of the present invention. 
       FIG. 4  is a schematic diagram of the controller circuit of  FIG. 2  shown in use, connected to a connector block or thermostat wires of an HVAC unit, in accordance with the one embodiment of the present invention. 
       FIG. 5  is a schematic diagram of a circuit tester in accordance with one embodiment of the present invention. 
       FIG. 6  is a diagram of the circuit tester of  FIG. 5  being in use according to one embodiment of the present invention. 
       FIG. 7  is a partial exploded view of a portable thermostatic controller and circuit tester in accordance with one embodiment of the present invention. 
       FIG. 8  is a front perspective view of a portable thermostatic controller and circuit tester in accordance with one particular embodiment of the present invention. 
   

   Referring now to the figures of the drawing in detail and first, particularly, to  FIG. 1  thereof, there is seen a portable thermostatic controller and circuit tester  10 . 
   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to  FIGS. 1–7 , there is shown a portable thermostatic controller and circuit tester  10  in accordance with a preferred embodiment of the present invention. 
   Once a technician has switched the thermostat of an HVAC unit to off and switched off the line voltage disconnect switch located on or nearby the unit, the portable thermostatic controller and circuit tester  10 , can be used to troubleshoot the unit and to make repairs. Once repairs are completed, the alligator clips  22 ,  24 ,  26  and  28  are attached to the low voltage connector block or thermostat wire connections (as shown more particularly in  FIG. 4 ) by removing twist-on wire connectors and exposing the bare wires. The technician can then go ahead and operate the controller circuit  70  of the portable thermostatic controller and circuit tester  10  by pressing the switches SW 1 , SW 2 , SW 3 , SW 4 , labeled in  FIG. 1  as power, fan, cool and heat, respectively. 
   The Controller Circuit and how it Works 
   Referring now more particularly to  FIG. 2 . The controller circuit  70  is basically a kind of portable thermostat without the sensor and circuit board. There is no PC board of semiconductor components involved in its circuitry. It consists of four push on/push off switches SW 1 , SW 2 , SW 3 , SW 4  arranged in parallel and soldered to four color coded wires, RED, GREEN, YELLOW, WHITE, 30 inches long from each switch with alligator clips  22 ,  24 ,  26 ,  28  soldered to the other ends of each wire RED, GREEN, YELLOW, WHITE. 
   With reference to  FIG. 2 , switches SW 1 –SW 4  are all in the normally open position, therefore making the circuit  70  off and inactive. In  FIG. 4  switches SW 1  and SW 2  are engaged in the ON mode. Both switches are now energized. Switch SW 1  passes low voltage power from the secondary output of the transformer T 1  onto Switch SW 2  which in turn passes the voltage to Relay RLY 1 . Relay RLY 1  would then be energized and closed. This allows line voltage to flow via Relay RLY 1  to the load. Switch SW 2  is connected to the green wire, which in HVAC trade is universally associated with the fan or blower. As particularly shown in  FIG. 4 , switches SW 3  and SW 4  are still in the open position, but when energized and closed via Switch SW 1 , they perform their roles the same way as Switch SW 2 . 
   Table 1 is a table showing the switch positions for different controller applications. 
   
     
       
             
             
             
             
             
             
             
           
         
             
               TABLE 1 
             
             
                 
             
             
                 
                 
                 
                 
                 
               WHITE 
                 
             
             
                 
                 
               Red 
               Green 
               YELLOW 
               SW4 
             
             
                 
                 
               SW1 
               SW2 
               SW3 
               HTR 
             
             
               APPLICATION 
               MODE 
               POWER 
               FAN 
               COMP 
               SOL 
               COMMENTS 
             
             
                 
             
           
           
             
               HEAT PUMP 
               COOL 
               ● 
               ● 
               ● 
               ● 
               SOLENOID 
             
             
                 
                 
                 
                 
                 
                 
               SWITCHES 
             
             
                 
                 
                 
                 
                 
                 
               REVERSING VALVE 
             
             
                 
                 
                 
                 
                 
                 
               TO COOLING MODE 
             
             
               HEAT PUMP 
               HEAT 
               ● 
               ● 
               ● 
                 
               SOLENOID 
             
             
                 
                 
                 
                 
                 
                 
               INACTIVE 
             
             
                 
                 
                 
                 
                 
                 
               REVERSING VALVE 
             
             
                 
                 
                 
                 
                 
                 
               PRE-SET FOR 
             
             
                 
                 
                 
                 
                 
                 
               HEATING 
             
             
               SPLIT 
               COOL 
               ● 
               ● 
               ● 
             
             
               SYSTEM 
             
             
               SPLIT 
               HEAT 
               ● 
               ● 
                 
               ● 
             
             
               SYSTEM 
             
             
                 
             
           
        
       
     
   
   The thermostatic controller and circuit tester  10  can also be used to determine if a thermostat is defective or if there is a broken wire between the thermostat and the units that comprise the air conditioning system. To do so, simply switch off the thermostat breaker or the disconnect switch, then dismantle thermostat from wall. Disconnect thermostat wires from their terminals. Now connect the controllers alligator clips  22 ,  24 ,  26 ,  28  to the ends of the exposed thermostat wires, RED to RED, YELLOW to YELLOW or BLUE, GREEN to GREEN and WHITE to WHITE. Now go ahead and switch on the breaker or the disconnect switch. Operate the system by means of the controller&#39;s push on/push off switches SW 1 –SW 4  of the thermostatic controller and circuit tester  10 . The technician then makes his diagnosis based upon the unit&#39;s performance and his findings. 
   The Test Circuit and how it Works 
   In  FIG. 5  there is an electronic circuit board ( 85  of  FIG. 7 ) as part of a variable circuit. This circuit comprises a light source L 3  (which is directed from the top face of the device  10 , away from the front face, as shown in  FIG. 1 ), a buzzer BUZZER for checking continuity and a tiny printed circuit board that consists of two bias resistors R 1  and R 2  and two neon lamps L 1  and L 2 . The test circuit  80  is designed for testing AC voltage. The light L 3  and buzzer BUZZER section of this circuit are powered by the two 1.5 VDC batteries  82 ,  84 =3 VDC. A DPDT slide switch SW 5  (on/off) is an integral part of this circuit and is used to switch roles. 
   Referring now to  FIGS. 1–7 , the circuit tester  80  and light source are operated as follows: the two 1.5 VDC batteries  82 ,  84 =3 VDC are arranged in series. A 3 VDC pre-focused flashlight bulb L 3  along with a momentary switch SW 6  arranged in parallel, is fed by the batteries. The momentary switch SW 6  was chosen, so as to save battery energy, by not being unintentionally left on for long periods. 
   This is the built-in flashlight operated by Switch SW 6 . The circuit  80  extends to a DPDT slide switch SW 5 . 
   From switch SW 6  a 3 VDC buzzer BUZZER and a 315 MA quick blow fuse FUSE (for buzzer protection) are arranged in series and connected to one end of switch SW 5  at position “A”. 
   When switch SW 5  is switched to position “A”, the circuit  80  is now in the mode for continuity test. The middle tags of switch SW 5  are connected to two output test lead jacks  14  and  16 . As illustrated at the bottom of  FIG. 5 , when the circuit tester via the detachable test leads  30   a ,  30   b  and probes  32 ,  35  are brought into contact with a metallic object such as a fuse  50 , the buzzer should emit an audible sound heard through the device casing holes ( 12  of  FIG. 1 ) if the fuse  50  is good. 
   On the other side of switch SW 5 , the switch is now engaged in position “B” as illustrated in  FIG. 6 . This section of the circuit  80  includes series and parallel arrangements of two resistors R 1  and R 2  and two neon lamps L 1  and L 2 . This is the voltage testing circuit. 
   The two bias resistors R 1 , R 2 , arranged in series, serves as a pair of controlling devices, that allows the right voltage to go to the right neon lamp L 1 , L 2 , thus illuminating it. The illustration in  FIG. 6  shows the test probes  32 ,  35  inserted in a wall socket  60  of a 120 VAC receptacle. 
   R 2  (33K) is the bias resistor for the 120 VAC neon lamp L 1 . With the test probes  32 ,  35  inserted into the 120 VAC wall socket  60 , the lamp L 1  will glow. 
   When the test probes are inserted in a 240 VAC source or outlet (not shown), the bias resistor R 1  (220K) allows the 240 VAC neon lamp L 2  to glow. 
   When not in use, the test circuit  80  should be switched to position “B”, which is also the off position for the battery&#39;s power.  FIG. 7  illustrates the actual assembly of the device. 
   Referring now to  FIG. 8 , there is shown one particular embodiment of the portable thermostatic controller and circuit tester  10 , wherein the project casing which houses the thermostatic controller and circuit tester  10  has specific dimensions. For example, in the embodiment of  FIG. 8 , the project casing which houses the thermostatic controller and circuit tester  10  is 5⅝ inches in length, 3¼ inches in width and 1½ inches deep. The controller leads extend 29½ inches from the project casing. Further, the test leads extend 44 inches from the casing  11 ′.