Electronically-Controlled Tankless Water Heater with Pilotless Ignition

Abstract

A rapid recovery tankless water heater operates by means of an electronic controller or card that regulates the operation of each of the system components, thereby optimizing gas consumption and minimizing the emission of gas pollutants. A multi-burner only ignites when certain conditions or predefined requirements in the electronic controller logic are met. Other factors contributing to improved water heater efficiency are: a) the water tank design which at the bottom has a water chamber surrounding the combustion chamber, and b) the use of a finned heat exchanger, which together with a core, successfully utilizes most of the thermal energy contained in the combustion gases. An air deflector device stops the entry of air currents at the top of the heater, thus stopping potential flame reversing and even flame extinction in the multi-burner.

1 - 5 . (canceled) 
     
     
         6 . A rapid-recovery tankless water heater, comprising:
 a multi-burner disposed below a combustion chamber;   a corrosion resistant water tank having a water chamber surrounding the combustion chamber;   a finned heat exchanger configured around a center core in an upper part of the combustion chamber, the core serving to redirect combustion gases through the heat exchanger;   and electrovalve configured with the multi-burner to control gas flow to the multi-burner;   an electronic controller, the electrovalve in communication with the electronic controller;   a bimetallic safety device disposed to detect water temperature within the water tank, the bimetallic safety device in communication with the electronic controller to cease operation of the water heater upon detected water temperature exceeding a preset value;   an ignition electrode in communication with the electronic controller to ignite the multi-burner;   an ionized electrode in communication with the electronic controller to detect ignition of the multi-burner;   a first temperature sensor at a cold water inlet to the water tank, and a second temperature sensor at a hot water outlet from the water tank, the first and second temperature sensors in communication with the electronic controller to generate a hot water demand flow signal upon a present temperature differential between the first and second temperature sensors; and   an air baffle configured atop the water tank to minimize air currents from entering the combustion chamber.   
     
     
         7 . The water heater as in  claim 6 , wherein the electronic controller is configured to send an ignition spark signal to the ignition electrode under the following conditions:
 (a) when there is a hot water demand flow signal and temperature sensed by the second temperature sensor at the hot water outlet is less than a preset cutoff temperature; or   (b) temperature detected by both of the first and second temperature sensors is less than a preset minimum ignition temperature value.   
     
     
         8 . The water heater as in  claim 7 , wherein the electronic controller is configured to send a signal to the electrovalve to stop gas flow to the multi-burner when both of the ignition signal conditions are not met. 
     
     
         9 . The water heater as in  claim 6 , wherein the electronic controller is configured to send a signal to the electrovalve to open and let gas flow to the multi-burner after a preset time delay from generating an ignition spark signal to the first electrode, 
     
     
         10 . The water heater as in  claim 9 , wherein the electronic controller is configured to send a single to the electrovalve to stop gas flow to the multi-burner under any of the following conditions: (a) an ignition signal is not received from the second electrode after a preset time from generation of the ignition spark signal to the first electrode; (b) an ignition signal received from the second electrode is intermittent during a preset time from generation of the ignition spark signal to the first electrode; or (c) the multi-burner goes out at any time.