Sudden no gas for pilot light, hot water heating system

njwebdevguy

Hello,



I turned my pilot light off for the summer and now it doesn't want to turn back on



We have a small home and its heated by a small American Standard gas hot water furnace. Our furnace has a Robertshaw control on it from which emerges the pilot light tube and the thermocouple tube.. - they light the gas burner.



The problem is no pilot. period... When I follow the usual procedure - push down button, turn to pilot position, attempt to light pilot, the pilot does nothing. It doesn't sputter.. It appears that no gas is being sent to it.



Everything seems to be the way it should be.. valve is on, gas burner switch is enabled, thermostat is not all the way down. I noted that the circulator does go on, (without any heat, because the house is cold- I dont remember if that is normal) 



Thinking that maybe the tiny orifice in the pilot was clogged I removed it to check its open, it is.



There is normal gas pressure because my other two gas appliances both work normally.



I don't know what to look at next. I'd prefer not to spend a lot of money, as we are on a tight budget right now.



Its not an emergency.. but any help is welcome...

JStar

RE

Before Tim gets hold of this thread, I would check out the Gas Heating forum and pick any thread with the word pilot in it.



I'd also make sure that the gas valve knob depresses completely, allowing the gas to flow to the pilot.

njwebdevguy

Pushing/turning as hard as I can

Something has definitely changed.



Also, thanks, I am looking at the gas heat forum. Any ideas are helpful.

kcopp

did you beed it...

off at the drip leg? is the T-couple dirty?

njwebdevguy

no gas coming from robertshaw control

The thermocouple looks fairly new and its not dirty, but I have not tested it electrically yet. The pilot orifices look okay, so far as far as I can tell, no gas is going to the pilot from the robertshaw gas valve/control.



would any of the electrical connections on that be able to tell me anything? I'm going to disconnect the thermocouple and see if it produces any voltage when I heat it over our gas stove or with a lighter.



Basically the pilot can't be lit, the tiny amount of gas that typically feeds it isn't present.

njwebdevguy

by drip leg, do you mean check the line for fluid?

water?  Its bone dry in my basement.. no water probs down there..And I think the part of the pilot line that was the lowest was the part that I checked when I checked the orifice. It had continuity and wasn't wet in any way.



Where is the thermocouple disconnected? right at the thermocouple itself, or at the control..

Mark Eatherton

Pushing and turning?

I think you are supposed to be turning (to the PILOT position) and THEN pushing...



These valves are fairly simple on the pilot side. If you definitely have gas, and you have the valve properly set, and the plunger engaged, you should be getting a pilot flame. If it is HARD to push, something else sounds wrong. You should be able to get about 3/8" to 1/2" of vertical travel on the knob if it is in the right position and operational. Your boiler didn't get flooded this last year did it? If yes, you should replace the valve and any other electric components that got submerged. Remember, you are working with things that can cause a lot of damage/death/destruction. If you're not comfortable with that, best call in a pro.



Check the basics first.



ME

njwebdevguy

Never been wet

as far as I know. We've been here for six years, and I grew up in this house decades ago.

RobG

Pilot

Just to make sure that you are doing this correctly:

1. Turn gas control knob to pilot position

2. Push down on gas control knob AND HOLD DOWN

3. While holding knob down attempt to light pilot.

4. If pilot lights, keep knob depressed for 60 seconds to let thermocouple heat.

5. Release knob. pilot should stay lit.

6. Turn gas valve knob to on position.

7. If the steps above do not work you should call a pro.

njwebdevguy

Thank you

Yes, Ive done all of the above, and have not seen as much as a sputter to indicate that gas is coming out of the pilot.



Both my wife and I have technical backgrounds. We're not overlooking something that basic.



I didn't change anything over the summer, I just turned off the pilot and the safety switch.



I'm going to check if the thermocouple produces current when heated. (I don't have the dummy load but I can test it with any given resistance.)



Is there anything else that I should examine? Voltages on the control terminals?



Also, the Robertshaw control has two covers that cover two adjustment screws. Should I be looking at them?  Last year a service technician misadjusted our boiler turning the flames way up, we had someone else adjust them back down but it still looks yellower than I think it should be. It gets cleaned every year, its not dirty.



The boiler was built in 1967 and its been a solid performer. We dont have the extra $3000 right now to spend on a new one.

RobG

Pilot light

There is no point in checking the thermocouple if the pilot will not light. As well, there will be no electrical issues regarding the pilot. For instance, if your power goes out, your pilot remains lit. The thermocouple simply tells the gas valve that the pilot is lit and it is safe to keep supplying gas to the pilot. If the pilot will not light and your sure there are no blockages in the pilot tube, the next step would be replacing the gas valve. If you are able, it is not hard to do. However, after a new valve is installed, you need to have the boiler set up by a pro with a combustion analyzer for safety and efficiency

Rob

njwebdevguy

Working now, but burner flame is too yellow

Hello,



Thank you, that did it..



I think that I was pushing, then turning, and I should have been turning then pushing.



We were able to get the pilot and burner to light and now the burner is going but I think its too yellow.



How do I adjust the default *burner* flame down slightly? It is a Robertshaw control and it has two adjustment screws that are covered by covers. The pilot looks good now, how can I adjust the burner level down to be blue, not yellow?



Thank you.

njwebdevguy

Think its fixed now

I need to recharge my camera then I will post before and after pics.



(Edited.. before and after pics will be in newer gas heating forum thread)



"before" burner flames were maybe six inches high and 75% yellow, now its an inch and a half or so high and 95% blue. Like the ads for gas heating.



We'll see how it heats the house..I guess.





I'