Pilot light almost goes out when it turns on

[gregory]

I've got a rental with a Bradford White water heater from 1999. It's old but I was hoping to get a little more life out of it since I just spent $6,000 rehabbing the place!

I haven't gone out to see it in person yet but this is how they describe it. Pilot light seems to be lit. When the water heater turns on they hear a click and the pilot light almost goes out and the burner doesn't light. Pilot light never goes out all the way.

Before I headed out I was hoping to get some ideas of what to check. Pilot light orifice clogged? Filter under water heater dirty? Any tips appreciated.

 

[TomFOhio]

You might have a weak thermocouple. This would be the cheapest fix. Clean the burner and pilot while your in there. See how that works. If still having problem call Bradford White tec service.

 

[gregory]

You might have a weak thermocouple. This would the cheapest fix. Clean the burner and pilot while your in there. See how that works. If still having problem call Bradford White tec service.

Thanks, I'll see if I can find one local. Their tech support was worthless. Here's a video of it, does this give any more clues on what it could be? The first click is me turning the temp dial up and you an hear it click on and hear the gas being delivered. The second click is me turning the temp dial back down which makes the burner light for a second. Then I do the same thing over again.

I took the whole burner assembly out and cleaned everything, didn't seem to help.

https://youtu.be/1UBDnymx5i4

 

[voletl]

Could have bad gas valve

 

[jeffmattero76]

A thermocouple is an $8 part you can easily get and a big box and replace. The pilot flame heats it, generating a small electric current, which "tells" the gas valve that it is safe to open and send gas through.

Since yours never lights, either the thermocouple is not sending that electrical signal, or, the gas valve itself is not responding to the signal.

 

[voletl]

The thermocouple creates its own voltage simple to keep the solenoid closed in the gas valve so there is gas constantly being feed to the piolt. If the thermocouple was broken there would be no pilot light.

 

[jeffmattero76]

The thermocouple creates its own voltage simple to keep the solenoid closed in the gas valve so there is gas constantly being feed to the piolt. If the thermocouple was broken there would be no pilot light.

Thanks for the clarification, but doesn't it also function as a "flame sensor" ?

 

[TomFOhio]

After watching your video and reading your post again and if it was installed in 1999 I wouldn't put a cent in a 20 year old water heater. Gas valves are very expensive. It looks like a strong pilot so its probably not the thermocouple. I know you don't want to hear this but it should probably be replaced. I would worry about the gas valve kicking on and not igniting the burner.

 

[voletl]

Thanks for the clarification, but doesn't it also function as a "flame sensor" ?

On an open standing pilot like that know all that thermocouple does is create milli voltage to make sure that solenoid is closed and that gas is being fed to the pilot if the pilot ever blew out or thermocouple failed that solenoid would open closing off the gas valve not allowing any gas to get through.

 

[jeffmattero76]

On an open standing pilot like that know all that thermocouple does is create milli voltage to make sure that solenoid is closed and that gas is being fed to the pilot if the pilot ever blew out or thermocouple failed that solenoid would open closing off the gas valve not allowing any gas to get through.

Ok, thanks. I guess that means he has a bad gas valve.

 

[voletl]

standing pilot no all that thermocouple does is create Milly voltage to keep the solenoid closed providing gas to the pilot if it ever failed the gas valve shut off

 

[gregory]

Thanks everyone. I believe it's the gas valve. I decided to just replace the entire water heater.

 

[jeffmattero76]

Thanks everyone. I believe it's the gas valve. I decided to just replace the entire water heater.

I also have rentals, and I replace the water heaters myself. I go to the property, hook a hose to the drain valve, turn off the water heater supply, open the drain valve, and cut both copper supply lines. On the cold side, I cut below the shutoff leaving a couple inches of copper stub.

I then go and get the new water heater, a gas flex line (usually 4' is enough, but measure to be sure), and two shark bite water flex lines. These are female hose fitting on one end that attaches to the nipples coming out of the top of the water heater, and a shark bite coupling that you simply push on to the copper pipes you cut earlier. I also create a "T"shaped drip leg out of black pipe. That is simply three six inch black nipples and a black tee fitting and a black cap. The middle leg of that T is inserted into the gas valve, the downward pipe is capped with the black cap, and the upward pipe connects to the new flex line. I have heard and read that this drip leg is not necessary, but it supposedly functions in trapping any debris that might be coming in with the gas, so that the debris doesn't get into the gas valve. The new heater and all of the parts cost around $450 - $500. It takes only a vouple of hours, including the time to go get the heater and parts.

The best part is that, the next time I have to replace this water heater, all that I will have to do is undo and reconnect 3 hose connections.

Good luck.

 

[gregory]

I also have rentals, and I replace the water heaters myself. I go to the property, hook a hose to the drain valve, turn off the water heater supply, open the drain valve, and cut both copper supply lines. On the cold side, I cut below the shutoff leaving a couple inches of copper stub.

I then go and get the new water heater, a gas flex line (usually 4' is enough, but measure to be sure), and two shark bite water flex lines. These are female hose fitting on one end that attaches to the nipples coming out of the top of the water heater, and a shark bite coupling that you simply push on to the copper pipes you cut earlier. I also create a "T"shaped drip leg out of black pipe. That is simply three six inch black nipples and a black tee fitting and a black cap. The middle leg of that T is inserted into the gas valve, the downward pipe is capped with the black cap, and the upward pipe connects to the new flex line. I have heard and read that this drip leg is not necessary, but it supposedly functions in trapping any debris that might be coming in with the gas, so that the debris doesn't get into the gas valve. The new heater and all of the parts cost around $450 - $500. It takes only a vouple of hours, including the time to go get the heater and parts.

The best part is that, the next time I have to replace this water heater, all that I will have to do is undo and reconnect 3 hose connections.

Good luck.

Hah! You said copper. My rental is all galvanized. I had some plumbers come and install a new one. They did a great job. Added a shut off valve and an expansion tank. The new owners will be thrilled.