Breaking Project: Fixing the Water Heater

Interesting fact about water heaters: Did you know that they have air filters which need to be cleaned every 6 months?

***Quick disclaimer - Messing around with a gas water heater can be dangerous if you don't know what you are doing.  Gas leaks can lead to explosions.  Carbon Monoxide buildup can lead to death.  If you are determined to fix your water heater yourself (which I take no responsibility for), play it safe. And if you smell gas at any time that you shouldn't be smelling gas, leave the house immediately and call the emergency gas leak number for your natural gas provider. ***

This is not my water heater:)

A couple days ago, my wife noticed that we didn't have any hot water, so I went down to the basement and checked the hot water heater. Sure enough, the pilot light was out.  When I tried to restart the pilot, however, I wasn't able to get it working.

When a pilot light goes out, it could be any number of things. The gas company might have shut off the gas to your house (unlikely, and you would probably know about it).  The gas line might be plugged.  A gust of wind might have blown out the pilot.  If you haven't cleaned the air filter in a while (almost 10 years in my case), then the most likely scenario is that your pilot was starved for oxygen.  Cleaning the filter should allow oxygen to flow.

The air filter, after a good cleaning.

The air filter is easy to overlook because it is on the very bottom part of the water heater, and it is hard to see unless you get down on the floor.  There are no screws or anything.  Just pop it off, scrub it clean, and pop it back into place.  I took the opportunity to clean out the inside of the water heater at the same time, using a vacuum and a brush.  It was full of cobwebs, dust, and debris.

Once the air filter was clean, I followed the instructions for relighting the pilot light, but I still couldn't get it to light.  This fix was getting a little more involved than I had hoped.

The gas is on.

I had a few ideas as to what the problem might be, so the first thing I did was shut off the gas to the water heater. The picture above shows what the valve looks like when the gas is on.  Turning it 90 degrees clockwise stops gas from flowing to the heater.  Please note that this still leaves some small amount of gas trapped in the pipe between the valve and the water heater.

The picture above shows where I next focused my attention.  Before going any further, I turned that big dial (temperature control) all the way clockwise, until it was in the "pilot" position.  Then I turned that black knob on top to the "off" position.  Next, I removed that metal guard that you see at the bottom of the image.  It just pops off.

Darkness in the view window = no flame

The big metal pipe in the picture above is the main gas line going into the water heater. The smaller silver pipe is the gas line for the pilot light.  The copper tube is the thermocouple (a sensor which helps shut off the gas if the temperature is too low - this prevents gas from continuing to build up if the pilot light is out).  The red-ish wire is part of the igniter, which provides the spark for starting the pilot light.

I disconnected all of the wires and pipes, removed this front plate with a ratchet, and took the whole burner unit out of the water heater.

This is not my burner, but it looks about the same.

This allowed me to do some more vacuuming and cleaning inside the water heater.  I noticed that the burner plate looked fine, but that there was some corrosion and wear at the spark gap end of the igniter.  I tried to scrub it with steel wool, reconnect the igniter wear, and tested it, but I still wasn't getting a spark.

At this point, I figured that it was the igniter that needed to be replaced, but I didn't want to buy that part and discover that something else was wrong too, so I purchased a whole new pilot assembly (which includes the thermocouple, igniter line, and pilot gas line).  It cost about $40 with 2-day shipping.

The old assembly that I removed.

Once the new assembly showed up, it was a quick and easy fix.  Take the old assembly off, put the new assembly on.  Before reinstalling the whole unit, I reconnected the igniter and tested it to see if I was getting a spark.  It gave me a good spark about half the time, which wasn't as good as I was expecting, but good enough to light a fire.

All I had to do then was reinstall the burner unit, and reconnect all the wires/gas lines/thermocouple.  I turned the gas back on and sniffed around for any possible gas leaks.  Not finding any, I followed the instructions for relighting the pilot light, and it relit on my second attempt.  Problem solved.

Total Time: 2 Hours
Total Cost: $42.93 ($31.94 for the assembly + 2-day shipping costs)