Scale Alarm System and Method

Abstract

A method for generating a scale service alert for a water heater includes calculating an initial bypass mixing percentage of water flowing through a bypass line, associating the calculated initial bypass mixing percentage of water with a detected position of a mixing valve to obtain a baseline feedback measurement, periodically comparing current measurements of the bypass mixing percentage of water and/or a current position of the mixing valve to the baseline feedback measurement, detecting blockages and triggering the scale service alert when the current position of the mixing valve changes by a pre-determined amount from the associated baseline position of the mixing valve to achieve the same bypass mixing percentage of water or when the current measurements of the bypass mixing percentage of water deviates from the initial bypass mixing percentage of water by a pre-determined factor.

What is claimed is: 
     
         1 . A method for generating a scale service alert in a water heater appliance having a mixing valve configured to mix two sources of water at different temperatures to achieve a mix temperature, a heat source, and a controller, the method comprising:
 measuring a first temperature of the water received from a cold water inlet, a second temperature of the water delivered from a hot water outlet from the heat source, and a third temperature of the water delivered from a mixing outlet of a mixing region;   calculating an initial bypass mixing percentage of water flowing through a bypass line based on the first temperature of the water, the second temperature of the water, and the third temperature of the water;   detecting a baseline position of the mixing valve;   associating the calculated initial bypass mixing percentage of water with the detected position of the mixing valve to obtain a baseline feedback measurement of the calculated initial bypass mixing percentage of water and the associated baseline position of the mixing valve;   periodically comparing current measurements of at least one of the bypass mixing percentage of water or a current position of the mixing valve to the baseline feedback measurement;   detecting blockages in at least one of the two sources of water when the current position of the mixing valve changes by a pre-determined amount from the associated baseline position of the mixing valve to achieve the same bypass mixing percentage of water or when the current measurements of the bypass mixing percentage of water deviates from the initial bypass mixing percentage of water by a pre-determined factor; and   when the current position of the mixing valve position changes by the pre-determined amount to achieve the same bypass mixing percentage of water or when the current measurements of the bypass mixing percentage of water deviates from the initial bypass mixing percentage of water by the pre-determined factor, triggering the scale service alert, thereby alerting the user to service the water heater appliance.   
     
     
         2 . The method of  claim 1 , wherein the measuring the first temperature, the second temperature, and the third temperature; the calculating the initial bypass mixing percentage of water flowing through the heat; the detecting the position of the mixing valve when the water heating appliance was new; and the associating the calculated initial bypass mixing percentage of water with the detected position of the mixing valve are performed after an initial installation of the water heater appliance and after a first call for heat. 
     
     
         3 . The method of  claim 1 , wherein the periodically comparing the current measurements of the bypass mixing percentage of water or the current position of the mixing valve to the baseline feedback measurement; the detecting blockages; the detecting the baseline position of the mixing valve; and the triggering the scale service alert are performed during a service of the water heater appliance and after one or more calls for heat. 
     
     
         4 . The method of  claim 1 , wherein the current measurements of the bypass mixing percentage of water comprise periodically calculating a current bypass mixing percentage of water flowing through the bypass line based on the first temperature of the water, the second temperature of the water, and the third temperature of the water. 
     
     
         5 . The method of  claim 1 , wherein the periodically comparing the current measurements of the bypass mixing percentage of water or the current position of the mixing valve to the baseline feedback measurement comprises:
 comparing the current measurements of the bypass mixing percentage of water to the calculated initial bypass mixing percentage of water, and   comparing the current position of the mixing valve to the baseline position of the mixing valve associated with the calculated initial bypass mixing percentage of water.   
     
     
         6 . The method of  claim 1 , further comprising storing the baseline feedback measurement in a non-volatile memory of the controller. 
     
     
         7 . The method of  claim 1 , further comprising:
 drawing heated water from the water heater appliance for a predetermined time period at a first flowrate;   detecting a mixing percentage of the two sources of water, including at least one of a mixing valve position, a total flowrate, and a percentage of water flowing through the heat source at the first flowrate;   detecting operation of the water heater appliance at a second flowrate and at least one of the mixing valve position, the total flowrate, or the percentage of water flowing through the heat source at the second flowrate;   comparing the mixing valve position at the first flowrate to the mixing valve position at the second flowrate, or the percentage of water flowing through the heat source at the first flowrate to the percentage of water flowing through the heat source at the second flowrate; and   detecting blockages in at least one of the two sources of water when the mixing valve position at the first flowrate and the mixing valve position at the second flowrate differ by a pre-determined amount, or when the percentage of water flowing through the heat source at the first flowrate and the percentage of water flowing through the heat source at the second flowrate differ by a pre-determined factor.   
     
     
         8 . The method of  claim 1 , wherein the service alert comprises at least one of an error message, a flashing light, a sound, or a push-up message or a notification to a computer, a cloud server, or a mobile device over a communication network. 
     
     
         9 . The method of  claim 8 , wherein the service alert is transmitted via a wired connection, a wireless communications protocol, or a non-wireless communications protocol. 
     
     
         10 . The method of  claim 9 , wherein the wireless communications protocol comprises at least one of a Bluetooth® communications protocol, Near Field Communications protocol, a WiFi communications protocol, ZigBee, Z-Wave, long range (LoRa), or LoRaWAN communications protocol. 
     
     
         11 . The method of  claim 1 , wherein the initial bypass mixing percentage of water flowing through the bypass line and the current measurements of the bypass mixing percentage of water are calculated as a ratio of a difference between the third temperature of the water and the second temperature of the water to the difference between the first temperature of the water and the second temperature of the water. 
     
     
         12 . The method of  claim 1 , wherein the initial bypass mixing percentage of water flowing through the bypass line and the current measurements of the bypass mixing percentage of water are calculated with a formula % cold =(T mix −T hx )/(−T hx +T cold ), wherein % cold  is the initial bypass mixing percentage of water flowing through the bypass line or the current measurements of the bypass mixing percentage of water, T cold  is the first temperature of the water, T hx  is the second temperature of the water, and T mix  is the third temperature of the water. 
     
     
         13 . The method of  claim 1 , further comprising counting steps of a stepper motor or using position feedback from a position sensor to determine the position of the mixing valve in response to temperature feedback based on the first temperature of the water, the second temperature of the water, and the third temperature of the water. 
     
     
         14 . The method of  claim 1 , wherein the scale service alert indicates blockages in at least one of the two sources of water from scale buildup that require service or maintenance of the water heater appliance. 
     
     
         15 . A water heater appliance configured to generate a scale service alert, the water heater appliance comprising:
 a heat source configured to receive water to be heated;   a mixing valve configured to receive water from two sources of water and to mix the water from the two sources of water;   at least one temperature sensor configured to sense a temperature of the water upstream of, downstream of, or within the heat source; and   a controller configured to:   calculate a mixing percentage from the two sources of water associated with a mixing valve position to obtain a baseline feedback measurement;   compare feedback measurements to the baseline feedback measurement;   detect blockages in at least one of the two sources of water when the mixing valve position requires a change of a pre-determined amount to achieve the same mixing percentage from the two sources of water; and   when the mixing valve position requires the change of the pre-determined amount to achieve the same mixing percentage from the two sources of water, trigger the scale service alert, thereby alerting the user to service the water heater appliance.   
     
     
         16 . The water heater appliance of  claim 15 , the water heater appliance being a tankless water heater, a storage water heater, a boiler, or a heat pump water heater. 
     
     
         17 . The water heater appliance of  claim 15 , wherein the mixing valve comprises a stepper motor configured to count steps or to use position feedback from a position sensor to determine the mixing valve position in response to temperature feedback based on a first temperature of the water at a cold water inlet, a second temperature of the water at a hot water outlet from the heat source, and a third temperature of the water at a mixing outlet of the mixing valve. 
     
     
         18 . The water heater appliance of  claim 15 , wherein the mixing percentage from the two sources of water comprises a bypass mixing percentage of water flowing through the bypass line based on the temperature of the water upstream of, downstream of, or within the heat source. 
     
     
         19 . The water heater appliance of  claim 15 , wherein the scale service alert comprises at least one of an error message, a flashing light, a sound, or a push-up message or a notification to a computer, a cloud server, or a mobile device over a communication network. 
     
     
         20 . A method for generating a scale service alert in a water heater appliance having a mixing region configured to deliver mixed water by mixing heated water received from a heat source and bypass water that bypasses the heat source, the method comprising:
 calculating a baseline bypass percentage of bypass water entering the mixing region based on baseline temperatures of the bypass water, the heated water, and the mixed water;   detecting a baseline position of a mixing valve in the mixing region associated with the baseline bypass percentage of bypass water to obtain a baseline feedback measurement including the baseline bypass percentage of bypass water and the baseline position of the mixing valve;   comparing the baseline feedback measurement to at least one of a subsequent bypass percentage of bypass water or a subsequent position of the mixing valve; and   when the subsequent bypass percentage of bypass water deviates from the baseline bypass percentage of bypass water by a pre-determined factor, or when the subsequent position of the mixing valve deviates from the baseline position of the mixing valve by a pre-determined factor, triggering the scale service alert, thereby alerting the user to service the water heater appliance.