Method of descaling tankless water heaters

Abstract

A controller for a tankless water heater is programmed to perform a descaling procedure that includes: closing a bypass valve to prevent fluid from bypassing a heat exchanger of the tankless water heater; activating a pump to cause a descaling solution to circulate through the tankless water heater; monitoring a flow rate of the descaling solution; and deactivating the pump responsive to one of: i) an amount of time that the pump is active exceeding a time limit, ii) the flow rate exceeding a first threshold, or iii) a change in the flow rate exceeding a second threshold.

What is claimed is: 
     
         1 . A controller for a tankless water heater, the tankless water heater comprising a fluid pathway defined by an inlet valve, a heat exchanger, a bypass valve for selectively bypassing the heat exchanger, and an outlet valve, the controller comprising:
 a processor; and   memory having instructions stored thereon that, when executed by the processor, cause the controller to execute a water heater descaling procedure, including by:
 causing the bypass valve to prevent fluid from bypassing the heat exchanger; 
 activating a pump to cause a descaling solution to circulate through the fluid pathway; 
 monitoring a flow rate of the descaling solution through the fluid pathway; and 
 deactivating the pump responsive to one of: i) an amount of time that the pump is active exceeding a time limit, ii) the flow rate exceeding a first threshold, or iii) a change in the flow rate exceeding a second threshold. 
   
     
     
         2 . The controller of  claim 1 , wherein the instructions further cause the controller to display, via a user interface, at least one of the flow rate or a remaining time for the water heater descaling procedure. 
     
     
         3 . The controller of  claim 1 , wherein the instructions further cause the controller to:
 detect that air is entering the fluid pathway based on the flow rate;   generate an alert indicating an abnormal condition based on air entering the fluid pathway; and   present the alert to a user via a user interface.   
     
     
         4 . The controller of  claim 1 , wherein the instructions further cause the controller to:
 track an amount of time that has elapsed since the water heater descaling procedure was completed; and   responsive to determining that the amount of time that has elapsed since the water heater descaling procedure was completed exceeds a predetermined limit, present a notification that prompts a user to reinitiate the water heater descaling procedure.   
     
     
         5 . The controller of  claim 1 , wherein the instructions further cause the controller to:
 receive a user input to terminate the water heater descaling procedure; and   deactivate the pump responsive to the user input and prior to any of: i) the amount of time that the pump is active exceeding the time limit, ii) the flow rate exceeding the first threshold, or iii) the change in the flow rate exceeding the second threshold.   
     
     
         6 . The controller of  claim 1 , wherein the flow rate is monitored using a sensor positioned along the fluid pathway. 
     
     
         7 . The controller of  claim 1 , wherein the pump is configured to circulate the descaling solution: i) from an external reservoir; ii) through the inlet valve, the bypass valve, the heat exchanger, and the outlet valve; and iii) back to the external reservoir. 
     
     
         8 . The controller of  claim 1 , wherein the instructions further cause the controller to prevent a heating element or a burner of the tankless water heater from being activated during the water heater descaling procedure. 
     
     
         9 . The controller of  claim 1 , wherein the instructions further cause the controller to receive a command to begin the water heater descaling procedure. 
     
     
         10 . The controller of  claim 1 , wherein the instructions further cause the controller to store an indication that the water heater descaling procedure has been completed. 
     
     
         11 . A method for descaling a heat exchanger of a tankless water heater, the tankless water heater comprising an electronically actuated bypass valve for selectively bypassing the tankless water heater, the method comprising:
 initiating a descaling procedure by transmitting, to the electronically actuated bypass valve, a first control signal to cause the electronically actuated bypass valve to prevent fluid from bypassing the tankless water heater;   transmitting, to a pump, a second control signal to activate the pump, wherein the pump circulates a descaling solution through the electronically actuated bypass valve and the heat exchanger when active;   monitoring, using a sensor, a flow rate of the descaling solution; and   transmitting, to the pump, a third control signal to cause the pump to deactivate responsive to at least one of: i) the flow rate exceeding a first threshold, or ii) a change in the flow rate exceeding a second threshold.   
     
     
         12 . The method of  claim 11 , wherein the third control signal is transmitted to the pump only in the event of the change in flow rate exceeding the second threshold. 
     
     
         13 . The method of  claim 11 , further comprising:
 detecting, using the sensor, that air is entering a fluid pathway of the tankless water heater based on the flow rate;   generating an alert indicating an abnormal condition based on air entering the fluid pathway; and   presenting the alert to a user via a user interface.   
     
     
         14 . The method of  claim 11 , further comprising:
 tracking an amount of time that has elapsed since the descaling procedure was completed; and   responsive to determining that the amount of time that has elapsed since the descaling procedure was completed exceeds a predetermined limit, presenting a notification that prompts a user to reinitiate the descaling procedure.   
     
     
         15 . The method of  claim 11 , further comprising:
 receiving a user input to terminate the descaling procedure; and   deactivating the pump responsive to the user input and prior to any of: i) the amount of time that the pump is active exceeding the time limit, ii) the flow rate exceeding the first threshold, or iii) the change in the flow rate exceeding the second threshold.   
     
     
         16 . The method of  claim 11 , further comprising preventing a heating element, or a burner, of the tankless water heater from being activated during the descaling procedure. 
     
     
         17 . The method of  claim 11 , further comprising receiving a command to begin the descaling procedure. 
     
     
         18 . The method of  claim 11 , further comprising storing an indication that the descaling procedure has been completed. 
     
     
         19 . A method for descaling a heat exchanger of a tankless water heater, the method comprising:
 receiving, via a user interface, a first user input to initiate a descaling procedure;   presenting, via the user interface, a first notification indicating that the tankless water heater is in a first mode of operation associated with the descaling procedure and prompting a user to activate an external pump;   initiating a timer responsive to detecting, using a flow rate sensor, that a fluid is being circulated through the heat exchanger of the tankless water heater by the external pump;   monitoring, using the flow rate sensor, a flow rate of the fluid; and   presenting, via the user interface, a second notification indicating that the descaling procedure is complete and prompting the user to deactivate the external pump responsive to determining that at least one of one of: i) an amount of time that the external pump is active exceeds a time limit, ii) the flow rate exceeds a first threshold, or iii) a change in the flow rate exceeds a second threshold.   
     
     
         20 . The method of  claim 19 , further comprising presenting, via the user interface, an indication of the flow rate and a remaining time for the descaling procedure.