We have a State Select Hot Water Heater (I don't have the model # was difficult for me to see). Our pilot light won't stay lit. It went out somtime Saturday afternoon. We were able to light it Saturday evening. It stayed lit for a while once it was lit Saturday night. The pilot light went out again sometime Sunday morning. I've lit it about 4 times and it keeps going out. What could be going on to cause the pilot light not to stay lit?

In all gas heated water heaters there are thermocouples,these are a safety feature designed to tell the control unit(outside the heat chamber) that it can safely open the gas valve,that there is actual flame present in the heating chamber.

In time,all thermocouples fail,the gas being introduced to the tip of them isn't pure,has oxygen,has moisture,etc.Eventually, it stops functioning as it should.

Removal and replacement of it is a simple procedure,with practice,this can be done in about 10-15 minutes.(yes,I have done many)

To remove,turn off the gas(on top of the control box outside the heater,the red knob.)

There are 2 lines coming down from the control box and the gas line coming in.

The copper line is for the thermocouple,it is thin and held in with a simple threaded nut,the other line is the gas line to the burner plate.

For ease of removal,I remove both lines and the entire burner plate from the control box.Take care how you remove the lines as they can kink,are soft,and threaded in weird ways,one clockwise,one counterclockwise, something like that:p(I can then also inspect the plate for wear)

The thermocouple is mounted simply by a push-in method.to remove,pull out and replace with a new one,you can leave the metal clip in(unless damaged upon removal)it simply holds the end at a space from the flame.

Look over the burner plate,looking for any rust or holes formed by excessive heat,water damage from a leak,etc.If none,reinstall the plate and lines.

Again,remember to pay close attention to thread direction and space provided for turning the nuts,I usually install the gas line after the thermocouple as the gas line gets in the way of my wrench if it is installed first.

Once installed and the flame door replaced,turn the knob and depress for relighting, looking at the flame tip and seeing if it is in contact with the TIP of the new piece,not the whole body,not the middle,but the tip.Wait the 60 seconds and keep your face away from the door as you turn the knob to burn.

Hope this helped!

KBC
PS: They are not real pricey either,I generally get 2 each time I have to replace one,just to have a replacement around in case it's a Sunday late and there isn't anyplace to get one till Monday after work:(

Keeping the second thermocouple in the heater room will be a great boon to you some day,trust me!

You can generally sand the thermocouple to with fine sandpaper to remove the oxide.

Better late than never. I have the same hot water still under parts warranty. I tried everything, clean the burner, thermocouple. etc. Everything appeared normal.

I called state select and their techs were very professional. They walked me through troubleshooting procedures (again). All voltages (Mv) in normal range.

Behind the black filter screen and mounted on the BOTTOM of the burner chamber is a flame arrestor also called Flammable Vapor Ignition Resistance or FVIR feature. It's a ceramic disk with about 1000 tiny holes in it. You really can't see it. I used an inspection mirror. It was there. You can also feel it with your hand. This gets lint, dust and dirt on it that build up.

Use a brush to clean the lint off and vacuum the brush. Do this as many times as needed. It solved my problem. I used a bottle brush and an old wheel cleaning brush.

My problem was not a component (thermocouple, gas control valve, etc.) I also had the skill to make those checks.

Another great source is hotwater101.com. They even have a step by step video which I viewed before I cleaned the FVIR on my hotwater heater. Hope this saves someone some frustration and the price of a service call.