Laundromat Water Heater not lighting or heating
Recently we relocated a Water Heater, although many people call it a “Hot Water Heater” the water is not hot until it gets heated so it’s a “Water Heater” but enough of that.
The water heater fired up and worked when we tested it and the tank heated up without a problem. The next day when I came into the store I heard the “Tick, Tick ,Tick” of the igniter but not the familiar dog barking sound after. After the Ticks you should here a “Woof” as the main burners light.
NOTE: This is for information only and you should not attempt to work on any gas appliances without proper training. Call a professional.
As I have many years experience working on burners I decided it was a good time to pull the burner out and provide some explanation of the operation and possible cause.
It’s really a simple concept for the tank type basic water heaters. The gas comes through a valve, sometimes a regulator depending on the supply pressure (we will discuss High and Low Pressure another time), next is the Gas Valve and then there is the Pilot Route and the Main Burner Route.
When the request for heat is made form the thermostat on the tank the pilot valve opens and gas is released through a small tube to the ignitor (spark plug) at the main burner. Once the pilot lights the flame heats a thermistor. This device changes resistance when it’s heated and tells the main burner that the Pilot light was lit and is still on.
Next step is the Gas Valve opens the flow to the main burner and all of the parts of it light from the pilot light. A slight “woof” sound is heard as the burner coves a large area and the gas lights across them from the pilot. Sort of like pouring a bucket of water on the floor, it takes less than a second to cover an area but it’s not instant.
When water heaters are installed, moved or any of the piping, valves or regulators upstream from the Gas Valve is worked on there is a chance that something will plug the Gas Valve. This could be some rust from the inside of the pipe, some pipe dope or putty used at the joints or some metal fragments from threading the pipe.
So, as in this case, it worked during the initial test but plugged up after a few cycles. A small puff of air will usually clean this out but in some cases the Gas Valve will need to be replaced.
NOTE: As I mentioned above- This is for information only and you should not attempt to work on any gas appliances without proper training. Call a professional.
Have a great day and Keep It Clean.