Water heater relay contact weld detection and mitigation

Abstract

Systems and methods of mitigating a contact weld of a first relay for selectively transmitting power to a first heating element of a water heating system. One method includes providing a signal to open the first relay, determining, following providing the signal to open the first relay, a first temperature measurement of a portion of a fluid within a tank of the water heating system via a temperature sensor, determining whether a difference between the first temperature measurement and a first target setpoint exceeds a first predetermined threshold, and activating, in response to the difference between the first temperature measurement and the first target setpoint exceeding the first predetermined threshold, a vibration device for a predetermined time period, the vibration device being positioned such that a resulting vibration from an activation of the vibration device is transmitted to the first relay.

What is claimed is: 
     
         1 . A method of mitigating a contact weld of a first relay for selectively transmitting power to a first heating element of a water heating system, the method comprising:
 providing a signal to open the first relay;   determining, following providing the signal to open the first relay, a first temperature measurement of a portion of a fluid within a tank of the water heating system via a temperature sensor;   determining whether a difference between the first temperature measurement and a first target setpoint exceeds a first predetermined threshold; and   activating, in response to the difference between the first temperature measurement and the first target setpoint exceeding the first predetermined threshold, a vibration device for a predetermined time period, the vibration device being positioned such that a resulting vibration from an activation of the vibration device is transmitted to the first relay.   
     
     
         2 . The method of  claim 1 , the method further comprising:
 determining a second temperature measurement of the fluid within the tank of the water heating system via the temperature sensor;   determining whether a difference between the second temperature measurement to a second target setpoint exceeds a second predetermined threshold; and   activating, in response to the difference between the second temperature measurement to the second target setpoint exceeding the second predetermined threshold, the vibration device.   
     
     
         3 . The method of  claim 2 , wherein at least one selected from the group consisting of the predetermined time period, a vibration frequency, and a vibration amplitude of a resulting vibration from the activation of the vibration device in response to the difference between the second temperature measurement to the second target setpoint exceeding the second predetermined threshold is greater than that of a resulting vibration from the activation of the vibration device in response to the difference between the first temperature measurement to the first target setpoint exceeding the first predetermined threshold. 
     
     
         4 . The method of  claim 1 , wherein the first temperature measurement is an average temperature. 
     
     
         5 . The method of  claim 1 , wherein the first temperature measurement is a change in temperature over time. 
     
     
         6 . The method of  claim 1 , wherein the vibration device is mounted on a housing containing the first relay. 
     
     
         7 . The method of  claim 1 , wherein the vibration device is mounted on a printed circuit board including the first relay. 
     
     
         8 . The method of  claim 1 , the method further comprising:
 providing a signal to close a second relay, wherein the second relay is configured to transmit power to a second heating element of the water heating system.   
     
     
         9 . The method of  claim 8 , the method further comprising:
 exceeding a circuit breaker limit via a combined power draw of both the first relay and the second relay.   
     
     
         10 . A water heating system comprising:
 a tank;   a first heating element coupled to a first portion of a fluid of the tank;   a temperature sensor configured to measure a temperature of the first portion of the tank;   a first relay configured to selectively transmit power to the first heating element;   a vibration device positioned such that a resulting vibration from an activation of the vibration device is transmitted to the first relay; and   a controller having an electronic processor and a memory, the controller configured to provide a signal to open the first relay,
 determine, following providing the signal to open the first relay, a first temperature measurement via the temperature sensor of the first portion of the tank, 
 determine whether a difference between the first temperature measurement and a first target setpoint exceeds a first predetermined threshold, and 
   activate, in response to the difference between the first temperature measurement and the first target setpoint exceeding the first predetermined threshold, the vibration device for a predetermined time period.   
     
     
         11 . The system of  claim 10 , wherein the controller is further configured to:
 determine a second temperature measurement of the fluid within the tank of the water heating system;   determine whether a difference between the second temperature measurement and a second target setpoint exceeds a second predetermined threshold; and   activate, in response to the difference between the second temperature measurement to the second target setpoint exceeding the second predetermined threshold, the vibration device.   
     
     
         12 . The system of  claim 11 , wherein at least one selected from the group consisting of the predetermined time period, a vibration frequency, and a vibration amplitude of a resulting vibration from the activation of the vibration device in response to the difference between the second temperature measurement to the second target setpoint exceeding the second predetermined threshold is greater than that of a resulting vibration from the activation of the vibration device in response to the difference between the first temperature measurement to the first target setpoint exceeding the first predetermined threshold. 
     
     
         13 . The system of  claim 10 , wherein the first temperature measurement is an average temperature. 
     
     
         14 . The system of  claim 10 , wherein the first temperature measurement is a change in temperature over time. 
     
     
         15 . The system of  claim 10 , wherein the vibration device is mounted on a housing containing the first relay. 
     
     
         16 . The system of  claim 10 , wherein the vibration device is mounted on a printed circuit board including the first relay. 
     
     
         17 . The system of  claim 10 , wherein the controller is further configured to:
 provide a signal to close a second relay, wherein the second relay is configured to transmit power to a second heating element of the water heating system.   
     
     
         18 . The system of  claim 17 , wherein a combined power draw of both the first relay and the second relay exceeds a circuit breaker limit. 
     
     
         19 . A method of mitigating a contact weld of a first relay for selectively transmitting power to a first heating element of a water heating system, the method comprising:
 providing a signal to open the first relay;   determining, following providing the signal to open the first relay, a first temperature measurement of a portion of a fluid of a tank of the water heating system via a temperature sensor;   determining whether a difference between the first temperature measurement and a first target setpoint exceeds a first predetermined threshold; and
 closing, in response to the difference between the first temperature measurement and the first target setpoint exceeding the first predetermined threshold, a second relay of the water heating system, wherein a combined power draw of both the first relay and the second relay exceeds a circuit breaker limit. 
   
     
     
         20 . A water heating system comprising:
 a tank;   a first heating element coupled to a first portion of the tank;   a second heating element coupled to a second portion of the tank;   a temperature sensor configured to measure a temperature of the first portion of the tank;   a first relay configured to selectively transmit power to the first heating element;   a second relay configured to selectively transmit power to the second heating element;   a vibration device positioned such that a resulting vibration from an activation of the vibration device is transmitted to the first relay; and   a controller having an electronic processor and a memory, the controller configured to provide a signal to open the first relay,
 determine, following providing the signal to open the first relay, a first temperature measurement via the temperature sensor of the first portion of a fluid of the tank, 
 determine whether a difference between the first temperature measurement to a first target setpoint exceeds a first predetermined threshold, and 
 close, in response to the difference between the first temperature measurement to the first target setpoint exceeding the first predetermined threshold, the second relay, wherein a combined power draw of both the first relay and the second relay exceeds a circuit breaker limit.