Have you ever had your hot water heater go out? Did it run out of hot water or did just the flame go out? IF so, no doubt the subsequent question you asked yourself was: Gee, do I have a gas or electric hot water tank? ! Well, if the answer is gas, then read on. We’ll address electric hot water tanks in another blog, as they do not have the safety device we want to discuss.
In our on going advice series for “desert dwellers” we explain that hot water heater safety device, the Thermocouple, or referred to sometimes as a Thermocoupler. This device senses when the pilot light is on. When the pilot is not lit, the gas valve will not turn the gas on. So if a gust of Monsoon winds blow out your pilot light, it shuts off the gas. If you didn’t have this safety device, gas would build up in the area your tank is housed in and could flash and cause an explosion. One important concept you should understand about your thermocouple is when it fails; it always fails in a closed position. What this also means, if you attempt to light that pilot flame, and it doesn’t stay lit after turning that knob to the desired temperature, your problem is the thermocouple. Now, at this point you have to make a decision, either call a plumber or replace it yourself. If you call a repairman and they say you need a new hot water heate, you need a second opinion. Here in the Arizona desert they last on average 8 years, so do your math before making that decision. If you decide to tackle the job yourself, keep reading. So, you have already discovered trying to light the pilot several times yields no flame. You may even find yourself holding that red button down longer than needed hoping to circumvent some sort of unknown quirk, trying desperately to get a flame. What’s occurring here is the essence of the safety feature of the thermocouple. After pushing in and holding down the red button, you are manually opening the valve to let the gas go to the pilot. The reason you need to hold that button down is to give the thermocouple a chance to heat up, thus opening up the valve. Without getting too technical, the heat from the pilot light heats the thermocouple and expands it to open the valve. Take the heat away and it constricts and closes the valve. You may want to go online and watch a video on how to replace your thermocouple, it’s about a fifteen or twenty minute job. A thermocouple costs roughly 15 to 20 dollars, conversely you could pay 60 to 70 dollars for a service call, plus parts and labor. This really is the most common failure for a hot water tank. By the way, if you need to light your pilot and you can’t see it, follow the thermocouple to it’s end, it will always be by the pilot light.
The advice in this article is copyrighted by AHA, and is no way a professional diagnosis or professional DIY instructions or advice.